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Tarantula

Tarantulas are large, hairy spiders belonging to the family Theraphosidae within the suborder Mygalomorphae of the order Araneae, encompassing 1,181 described species worldwide as of November 2025.^[1]^[2] These robust arachnids, with the largest species measuring up to 11 inches (28 cm) in leg span and weighing up to 6 ounces (175 g), are characterized by their downward-striking chelicerae, eight legs covered in sensory hairs, and abdomens bearing urticating hairs for defense.^[3]^[4] Primarily inhabiting tropical, subtropical, and arid regions across the Southern Hemisphere—with notable diversity in South America, Africa, and Asia, and fewer species in North America—tarantulas are typically solitary, ground-dwelling burrowers that line their retreats with silk.^[3]^[4] Some species, such as arboreal forms, inhabit tree hollows or foliage, adapting to diverse ecosystems from deserts to rainforests.^[3] As nocturnal ambush predators, they feed on insects, small vertebrates like frogs and lizards, and occasionally birds or rodents, immobilizing prey with venom injected via large fangs.^[3] Tarantulas exhibit remarkable longevity among arachnids, with females often living 20 to 30 years in the wild, while males typically survive only 5 to 10 years after reaching maturity.^[3]^[4] Their life cycle includes multiple molts, during which they shed their exoskeleton to grow and regenerate lost limbs.^[3] Reproduction involves males performing courtship dances to approach receptive females, though encounters can turn aggressive, leading to cannibalism.^[4] Despite their fearsome reputation, tarantula venom is generally mild and comparable to a bee sting in potency for humans, causing localized pain and swelling but rarely severe effects or fatalities.^[5] Many species rely more on flicking barbed urticating hairs, which embed in skin or eyes to deter threats, rather than biting.^[4] Popular in the pet trade due to their docile nature and striking appearances—ranging from earthy browns to vibrant blues and greens—tarantulas play key ecological roles as predators controlling invertebrate populations.^[3]^[1]

Introduction

Overview

Tarantulas are large, often hairy spiders belonging to the family Theraphosidae, a group within the suborder Mygalomorphae.^[6] As of November 2025, the family comprises 186 genera and 1,181 species.^[2] These arachnids are distinguished by their robust bodies covered in dense hairs and impressive size, with leg spans reaching up to 30 cm in species like the Goliath birdeater (Theraphosa blondi).^[7] Most tarantulas are ground-dwelling and nocturnal hunters, ambushing prey such as insects, small vertebrates, and other spiders from burrows or silk-lined retreats.^[8] They inhabit tropical and subtropical regions worldwide, including parts of Africa, Asia, Australia, and the Americas, though some species adapt to arid environments.^[3] Due to their generally docile temperament in captivity, long lifespans (up to 25 years for females), and low-maintenance care requirements, tarantulas are popular exotic pets among enthusiasts.^[9] A common misconception, particularly in North America, is that the term "tarantula" applies to large wolf spiders of the family Lycosidae; however, true tarantulas are exclusively members of Theraphosidae.^[10] The name originates from the European wolf spider Lycosa tarantula, which was historically linked to tarantism—a hysterical condition believed to result from its bite and cured by frenzied dancing, prevalent in southern Italy during the 16th and 17th centuries.^[11]

Etymology

The word "tarantula" derives from the Medieval Latin tarantula and Italian tarantola, both originating from Taranto, a seaport city in southern Italy (ancient Greek Tárās, Latin Tarentum).^[12]^[13] It first appeared in English around the 1560s, initially referring to Lycosa tarantula, a species of wolf spider (Lycosidae) native to the Mediterranean region around Taranto, noted for its prevalence there.^[12] The term became linked to tarantism, a form of hysteria or dance mania reported in 15th- to 17th-century Apulia, Italy, where victims believed they were bitten by the spider and could only be cured through vigorous dancing to the rhythm of the tarantella.^[12] Over time, European explorers and naturalists extended the name "tarantula" to large, hairy spiders encountered in the Americas, particularly those in the mygalomorph infraorder, shifting its application from the araneomorph wolf spider to unrelated species.^[4] By the 18th and 19th centuries, it commonly denoted members of the family Theraphosidae, distinguishing these burrowing, robust mygalomorphs from other spider groups while retaining the folkloric connotation of size and perceived danger.^[14] This evolution reflects early colonial descriptions, where the unfamiliar New World spiders evoked associations with the Italian "tarantula" due to their hairy appearance and size.^[4] The scientific family name Theraphosidae, established by Tamerlan Thorell in 1869, derives from the genus Theraphosa (type genus), itself from Ancient Greek thḗrā ("hunting" or "chase") and phṓs ("light" or interpreted as "man" in compound forms), evoking "huntsman" and alluding to the spider's predatory nature.^[15] Despite the common name's origins, Theraphosidae specifically encompasses over 1,000 mygalomorph species worldwide, emphasizing their basal evolutionary position among spiders.^[16] Many genus names within Theraphosidae incorporate the Greek root pélma (πέλμα), meaning "sole of the foot" and referring to the tarsal scopulae or adhesive pads on the spiders' feet, a key morphological feature.^[17] For instance, Aphonopelma combines a- (without) + phōnḗ (sound) + pélma, denoting "soundless sole" or a silent theraphosid lacking certain stridulatory structures on the foot soles.^[18] Similarly, Brachypelma merges brachýs (short) + pélma, describing species with abbreviated scopulae.^[17] This suffix, popularized by 19th-century arachnologists like Reginald Innes Pocock, underscores the family's diagnostic pedal adaptations.^[17]

Description

Morphology and Identification

Tarantulas exhibit a distinctive body structure typical of mygalomorph spiders, consisting of two main tagmata: a cephalothorax (prosoma), which fuses the head and thorax, and an unsegmented abdomen (opisthosoma), connected by a narrow pedicel. The cephalothorax bears eight walking legs arranged in pairs, segmented pedipalps that function as sensory appendages, and forward-projecting chelicerae equipped with hollow fangs for injecting venom into prey. ^[19] ^[20] The body and appendages are densely covered in setae, including specialized types such as urticating hairs—irritating, barbed structures primarily on the abdomen and legs of New World species, deployed for defense—and sensory hairs that detect touch, vibrations, and air currents. ^[20] ^[19] Tarantulas display significant size variation, with body lengths ranging from 1 to 10 cm and leg spans reaching up to 30 cm in large species like Theraphosa spp., while coloration spans subdued browns and grays to vibrant blues and greens in certain species, such as the iridescent blue legs of Cyriopagopus lividus. ^[21] ^[22] Key identification features include the presence of two pairs of book lungs—slit-like respiratory organs on the ventral abdomen, a primitive trait shared among mygalomorphs—and parallel chelicerae that articulate vertically, unlike the diagonal movement in most araneomorph spiders. ^[23] ^[19] Tarantulas lack the prominent, multi-segmented spinnerets of orb-weaving araneomorphs, instead possessing short, inconspicuous spinnerets used minimally for silk production, such as burrow lining. ^[19] Within mygalomorphs, Theraphosidae (tarantulas) are distinguished by features like urticating hairs and robust builds, contrasting with the silk trapdoors of some diplurids or the smaller size of actinopodids. ^[20] Specialized features include stridulating organs, typically comprising modified setae on the legs or palps that rub against ridged surfaces to produce warning sounds, present in many theraphosid species. ^[24]

Sexual Dimorphism

Tarantulas in the family Theraphosidae exhibit pronounced sexual dimorphism, particularly in body size and proportions, with females generally larger and bulkier than males. Adult females often reach body lengths of up to 10 cm, reflecting their investment in reproductive capacity, while males are slimmer with relatively shorter bodies but longer legs that can span up to 15 cm, aiding in mobility during mate-searching.^[25] This female-biased sexual size dimorphism (SSD) in overall body mass is consistent across the family, though the degree varies by species, such as in larger genera like Theraphosa where females can exceed 100 g. Structural differences are most evident in reproductive organs and appendages. Mature males develop tibial apophyses—hook-like spurs on the tibia of the first (and sometimes second) pair of legs—used to clasp the female's chelicerae during copulation, a trait absent in females.^[25] Additionally, male pedipalps become bulbous, terminating in a sclerotized embolus for sperm transfer, while females possess paired spermathecae in the epigyne for long-term sperm storage.^[26] These adaptations highlight the divergence in reproductive strategies between sexes. Lifespan dimorphism is stark, with females outliving males significantly due to continued molting and somatic maintenance post-maturity. Females can live 15–25 years or more, depending on species and environmental factors, whereas males typically survive only 3–7 years after reaching sexual maturity, often dying shortly after their final molt without further reproduction. In some cases, mature males exhibit reduced longevity linked to elevated metabolic rates and wandering behavior. In certain species, color and pattern dimorphism emerges at maturity, with males displaying brighter or more iridescent hues to signal readiness for mating. For example, in Pamphobeteus antinous, mature males feature vivid metallic blue bristles on their legs and pedipalps, contrasting with the more subdued tones of females.^[27] Such traits, observed in genera like Haplopelma and Psalmopoeus, underscore the role of visual cues in sexual selection. These dimorphisms collectively influence mating success, as males' slimmer builds and specialized structures facilitate sperm delivery but increase vulnerability to predation during dispersal, while females' robust form supports egg production and burrow defense.^[25]

Distribution and Habitat

Geographic Range

Tarantulas, members of the family Theraphosidae, exhibit a predominantly tropical and subtropical distribution, with 1,133 species documented worldwide as of November 2025.^[28] The family is largely confined to warmer regions, showing a marked absence from colder climates such as northern temperate zones and polar areas, reflecting their physiological constraints on thermoregulation and habitat suitability.^[1] This pattern aligns with a Gondwanan origin, where ancestral lineages diversified following the breakup of the supercontinent, leading to vicariant distributions across southern landmasses. The Americas represent the epicenter of tarantula diversity, hosting approximately 650 species across North, Central, and South America, from the southwestern United States (e.g., Arizona and Texas) through Mexico and extending to Argentina and beyond.^[1] Africa supports more than 150 species, primarily in sub-Saharan regions including Madagascar, while Asia harbors around 200 species, concentrated in Southeast Asia, India, and the Middle East.^[1] Australia has comparatively few, with only about six native species, such as those in the genus Selenocosmia, mostly in northern tropical areas.^[1] Biodiversity hotspots underscore regional concentrations, with Brazil's Atlantic Forest and Mexico's highlands standing out for their exceptional species richness—Brazil alone accounts for approximately 210 species, and Mexico ranks second globally with around 100.^[1] Introduced populations remain rare and localized, often resulting from the pet trade rather than widespread invasions. For instance, the Mexican redrump tarantula (Brachypelma vagans) has established small feral populations in Florida, USA, outside its native Central American range.^[29] In Europe, occasional escapes occur, but no self-sustaining populations have been reported, limiting non-native distributions to isolated incidents.^[30]

Habitat Preferences

Tarantulas of the family Theraphosidae occupy a diverse array of general habitats worldwide, predominantly in tropical and subtropical regions, including forests, deserts, semi-deserts, grasslands, and shrublands.^[31] Many species construct burrows in loose soil or seek shelter under rocks, logs, or leaf litter to regulate environmental exposure.^[32] These habitats provide the necessary stability for burrowing and foraging, with a strong concentration in warm climates across the Americas, Africa, and Asia.^[33] Within these environments, tarantulas exhibit distinct microhabitat preferences that reflect their ecological niches. Terrestrial species, such as those in the genus Aphonopelma, typically inhabit ground-level burrows in arid or semi-arid areas, while arboreal forms construct silk-lined tubes in tree hollows, bark crevices, or foliage in humid forests.^[31] Saxicolous tarantulas, adapted to rocky terrains, often reside in crevices or under boulders in mountainous or outcrop-dominated landscapes, enhancing protection from predators and desiccation.^[34] Tarantulas demonstrate varied adaptations to moisture and temperature conditions suited to their habitats. Some species are hygrophilous, thriving in moist tropical forests with relative humidity above 70% to prevent dehydration, whereas xerophilous forms in desert regions tolerate low humidity levels below 40% through behavioral microhabitat selection and physiological tolerance.^[31] Optimal temperature ranges generally fall between 15°C and 30°C, with many species exhibiting peak activity and reproduction in the 20-28°C zone to balance metabolic demands and avoid thermal stress.^[35] Habitat threats, particularly deforestation, severely impact tarantula populations in biodiversity hotspots like the Amazon rainforest and Southeast Asian forests, where logging and agricultural expansion fragment suitable microhabitats and reduce burrow viability.^[34] For instance, species in the Amazon Basin face accelerated habitat loss, with over 10% of forest cover removed between 2001 and 2019, directly threatening arboreal and terrestrial niches.^[36] In Southeast Asia, similar deforestation pressures in regions like Thailand and the Philippines exacerbate risks for endemic species reliant on undisturbed forest understories.^[37] Desert-adapted tarantulas, such as Aphonopelma chalcodes in the arid US Southwest, exemplify xerophilous preferences by inhabiting Sonoran Desert shrublands and semi-arid grasslands, where they dig deep burrows to access cooler, moister subsurface layers during extreme heat.^[38] These species endure temperatures up to 40°C at the surface but prefer burrow depths maintaining 20-25°C, highlighting their resilience in resource-scarce environments.^[32]

Behavior

Daily Habits

Tarantulas exhibit primarily nocturnal or crepuscular activity patterns, emerging from their retreats at dusk or during the night to forage and hunt. As ambush predators, they typically position themselves near burrow entrances or on silk mats, remaining motionless for extended periods to detect vibrations from passing prey. This behavior minimizes exposure to diurnal predators and aligns with the activity of many of their insect and small vertebrate prey items.^[39]^[40] Feeding in tarantulas involves opportunistic pouncing on detected prey, which is subdued using fangs to inject paralytic venom and digestive enzymes. Their diet consists mainly of insects such as crickets and beetles, but larger species may consume small vertebrates including frogs, lizards, mice, and occasionally birds. After immobilization, tarantulas regurgitate enzymatic fluids onto the prey to liquefy internal tissues, which are then ingested through a sucking action, leaving behind indigestible exoskeletons or bones.^[41]^[42] Most tarantula species are solitary throughout their lives, with individuals aggressively defending territories and often resorting to cannibalism if encounters occur outside of brief mating interactions. However, rare exceptions exist among certain arboreal genera like Poecilotheria, where subsocial behaviors—such as temporary tolerance of offspring or siblings near retreats—have been observed, though full communal living remains uncommon and aggression persists in adults.^[43]^[44] Tarantulas produce minimal silk compared to orb-weaving spiders, using it primarily to line burrows or construct tubular retreats for protection and molting, rather than building capture webs for hunting. These silk linings help maintain humidity and structural integrity in underground or arboreal shelters, with some species adding trip lines at burrow entrances to sense approaching prey.^[45]^[40]

Locomotion and Appendages

Tarantulas possess eight legs adapted for walking, climbing, and burrowing, enabling versatile locomotion across diverse terrains. These legs facilitate movement through a combination of muscular flexion and hydraulic extension, where hemolymph pressure generated by prosomal muscles extends the femur-patella (proximal) and tibia-metatarsal (distal) joints, allowing for efficient stride propagation.^[46] In bursts of speed, such as during hunting or evasion, tarantulas like Aphonopelma hentzi can achieve velocities up to 0.53 m/s at optimal temperatures around 38°C, primarily by increasing stride frequency rather than length.^[46] The pedipalps, located anterior to the first pair of legs, serve as multifunctional appendages with prominent sensory roles. Covered in chemosensory setae, they detect chemical cues for tasting prey and manipulating food items during feeding.^[19] In males, the pedipalps are modified into bulbous copulatory organs that transfer sperm directly to the female during mating, a process requiring precise insertion into the spermathecae.^[47] Tarantulas' chelicerae, robust mouthparts bearing fangs, are essential for locomotion-related activities like prey capture. These appendages grasp and envenomate victims through downward strikes, with the fangs injecting paralytic toxins to subdue them.^[48] Unique to mygalomorph spiders, including tarantulas, the chelicerae exhibit a parallel orientation, allowing vertical movement in a plane aligned with the body's long axis, which contrasts with the transverse action in araneomorphs.^[49] Sensory structures on the legs enhance locomotor precision and environmental awareness. Trichobothria, fine sensory hairs distributed along the legs, detect subtle air currents and vibrations, aiding in navigation and prey localization from afar. Additionally, slit sensilla—slit-shaped mechanoreceptors embedded in the leg exoskeleton—monitor cuticular strain during movement, providing feedback on joint loading and substrate interactions to prevent overload.^[50] For burrowing and climbing, tarantulas employ silk from abdominal spinnerets as anchors to stabilize burrows or secure positions on uneven surfaces, lining tunnels with silk sheets for reinforcement.^[51] Arboreal species, such as those in the genus Avicularia, feature specialized adhesive pads on their tarsi, composed of densely packed setae that generate van der Waals forces for clinging to smooth vertical substrates like tree bark or leaves.^[52]

Defense and Predation

Predators

Tarantulas face predation from a diverse array of animals across their habitats, serving as prey in mid-level trophic interactions that help regulate arthropod populations.^[53] Common predators include insects such as the tarantula hawk wasp (Pepsis spp.), which paralyzes adult tarantulas with its sting to provision larvae, often targeting burrowing species in arid regions.^[8] Reptiles like larger lizards (e.g., chuckwallas) and snakes (e.g., coachwhips) frequently consume tarantulas, ambushing them near burrows or on the ground.^[54] Birds also play a significant role, with species such as roadrunners (Geococcyx californianus) in the Americas actively hunting tarantulas, using their speed to capture and consume them whole.^[55] Mammalian predators include coyotes (Canis latrans), foxes (e.g., kit foxes), and skunks in North American deserts, which dig out or opportunistically eat tarantulas during foraging.^[54]^[56] In tropical Americas, coatis (Nasua spp.) raid burrows and prey on tarantulas, employing group tactics to overcome defenses, while introduced small Indian mongooses (Herpestes javanicus) dig into burrows to extract and consume them.^[57]^[58] Army ants (e.g., Eciton spp.) in Neotropical regions can overwhelm and prey on tarantulas by invading burrows, though attacks often fail due to the spiders' physical defenses.^[59] Many predators preferentially target vulnerable life stages, such as spiderlings dispersing after egg sac hatching or unguarded egg sacs, which increases mortality rates during these periods.^[33] This selective predation contributes to limiting tarantula population densities, preventing overabundance in localized areas and maintaining ecological balance.^[60] Human-induced habitat loss exacerbates these pressures by fragmenting populations, reducing burrow availability, and increasing exposure to predators in altered landscapes.^[33]

Defensive Mechanisms

Tarantulas utilize a range of defensive strategies to deter predators, including physical, chemical, and behavioral adaptations that emphasize deterrence over aggression. These mechanisms vary by species and region, with New World tarantulas often relying on specialized irritants, while Old World species prioritize evasion and potent bites. Primary defenses include urticating hairs, postural displays with acoustic signals, envenomation, and rapid retreat to concealed retreats. Urticating hairs represent one of the most distinctive active defenses in many tarantula species, particularly those in the New World, where they are modified barbed setae on the abdominal scopula.^[61] These hairs are actively dispersed by kicking the hind legs against the abdomen, propelling them toward threats in a process known as hair-flicking or bombardment, which can embed in skin, eyes, or respiratory tissues to cause mechanical irritation, inflammation, and pain.^[61] Morphologically, urticating hairs are classified into seven types (I-VII) based on structure, ontogeny, and dispersal method; for instance, Type I hairs (common in Theraphosinae genera like Aphonopelma and Brachypelma) are short and robust with terminal barbs, while Type II hairs (in Aviculariinae like Avicularia) are longer and more easily airborne for broader coverage.^[61] Types III-VI are prevalent in South American Theraphosinae and Psalmopoeinae, with variations in length, shape, and irritancy; Type VII is rarer, found only in Colombian Kankuamo species.^[61] Beyond active use, some species passively incorporate these hairs into silk mats lining burrows or egg sacs, providing ongoing protection against intruders.^[61] This defense is highly effective against vertebrate predators like birds and mammals, as the hairs' penetration and persistence can impair vision or movement.^[61] The dense covering of non-urticating sensory hairs on tarantulas' bodies likely evolved as an additional defense, deterring predatory ants such as army ants by making attacks mechanically difficult.^[59] Tarantulas also form symbiotic associations with other species, such as amphibians, snakes, whip spiders (Amblypygi), and harvestmen (Opiliones), which cohabit burrows and provide mutual protection from predators through collective vigilance or repellent secretions. Over 60 such partnerships with amphibians have been documented across multiple countries, with new reports of cohabitation with snakes and other arachnids.^[59] In response to immediate threats, tarantulas frequently adopt a threat posture, elevating the front of the body on the hind legs and hind tarsi while extending the pedipalps and displaying the chelicerae with fangs, serving as a visual and postural warning to intimidate attackers.^[5] Accompanying this display, many species produce stridulation sounds—a rasping or hissing noise generated by rubbing specialized file-like setae on one body part against a ridged or toothed surface on another, such as the palpal coxa or leg femora.^[62] In Theraphosa leblondi, for example, stridulation occurs via unique setal entanglement, where hooked setae on the pedipalp and leg femora interlock and release to create audible vibrations, functioning as an acoustic aposematic signal to deter vertebrates.^[62] This auditory component enhances the threat posture's deterrent effect, particularly in nocturnal or low-visibility encounters.^[62] If deterrence fails, tarantulas may resort to biting, delivering venom through their fangs that is ecologically tuned for immobilizing insect prey and small vertebrates rather than large mammals.^[5] The venom comprises a complex mixture of peptides, neurotoxins, enzymes, and nucleotides that disrupt nerve function, causing rapid paralysis in targeted organisms.^[5] While highly potent against arthropods and amphibians—leading to quick prey capture and self-defense—these venoms induce only localized pain, edema, and muscle spasms in humans, underscoring their role in ecological deterrence over lethality to larger threats.^[5] As a passive and primary avoidance tactic, tarantulas often flee swiftly to silk-lined burrows or retreats, where they employ camouflage by covering entrances with soil, silk, and debris to blend into the environment and evade detection.^[61] This burrowing behavior provides a secure refuge, sometimes enhanced with urticating hairs in the silk lining for added protection against burrow invaders.^[61] Defensive strategies exhibit regional variation, with New World species (Americas) predominantly featuring urticating hairs and milder venoms, enabling non-lethal irritation as a first line of defense.^[61] In contrast, Old World tarantulas (Africa, Asia, Australia) generally lack these setae, compensating with faster locomotion, more aggressive threat postures, and venoms that emphasize biting potency for direct confrontation.^[61]

Physiology

Digestive System

Tarantulas employ extra-oral digestion to process prey, beginning with the injection of venom through their fangs to immobilize the victim, followed by the regurgitation of digestive fluids from the midgut onto the prey to liquefy its tissues.^[63] This process allows tarantulas to break down complex proteins, lipids, and carbohydrates externally before ingestion, maximizing nutrient extraction from solid food sources.^[64] The liquefied contents are then sucked up using specialized mouthparts, including the pharynx and chelicerae, while undigested solids, such as exoskeletons, are later regurgitated as compact pellets.^[65] The digestive tract of tarantulas consists of a foregut, midgut, and hindgut, forming a tubular system that extends along the body length. The foregut, located in the prosoma, includes the esophagus and a muscular sucking stomach (pharynx) that pumps fluids inward.^[65] The midgut, primarily in the opisthosoma, features diverticula—blind extensions that branch into the legs and facilitate storage, further enzymatic breakdown, and absorption of nutrients through pinocytosis in epithelial cells.^[63] The hindgut, also in the opisthosoma, reabsorbs water and ions before waste expulsion via the anus, with Malpighian tubules aiding in excretion.^[65] Digestion proceeds in phases: initial enzymatic hydrolysis outside the body using a cocktail of proteases (e.g., astacin-like metallopeptidases, cysteine peptidases like cathepsin L), lipases, and carbohydrases (e.g., alpha-amylase, chitinase) secreted from midgut cells.^[64] Once ingested, the fluid reaches the midgut for intracellular digestion and absorption, with the alkaline pH (around 7.4) optimizing enzyme activity, particularly for amylases and other hydrolases.^[66] Gut symbiotic bacteria, such as those from Proteobacteria (e.g., Burkholderia, Ralstonia), contribute to this by aiding in carbohydrate and amino acid metabolism, enhancing overall nutrient breakdown.^[67] This system enables high efficiency in protein and nutrient absorption, allowing tarantulas to derive substantial energy from a single meal and endure extended fasting periods of up to several months, supported by stored reserves in diverticula and low metabolic rates during starvation.^[66] Such adaptations suit their ambush predation strategy, where meals are infrequent but large.^[63]

Sensory and Nervous Systems

Tarantulas, like other mygalomorph spiders, possess eight eyes arranged in two rows, consisting of two principal eyes (anterior median) and six secondary eyes (anterior lateral, posterior median, and posterior lateral). The principal eyes primarily detect light intensity and shadows rather than forming detailed images, while the secondary eyes are specialized for sensing motion and changes in light patterns, aiding in the detection of approaching threats or prey. However, tarantulas lack color vision in the typical sense, with their visual acuity being notably poor compared to araneomorph spiders, limiting their reliance on eyesight for navigation or hunting.^[68]^[41] Mechanoreception plays a dominant role in tarantula sensory perception, facilitated by specialized cuticular structures such as trichobothria (fine hairs sensitive to air currents and distant vibrations), tactile setae (short hairs detecting direct contact), and slit sensilla (lyrifom organs embedded in the exoskeleton that respond to substrate strain and vibrations). These mechanoreceptors allow tarantulas to locate prey through vibrations transmitted via the ground, even in complete darkness, and to perceive subtle air movements that signal nearby disturbances. Chemoreception complements this system, with contact chemoreceptors located on the tarsi of the legs and pedipalps, enabling the detection of chemical cues such as pheromones or prey scents upon direct contact; these are often manifested as ribbed, pore-tipped setae that function as taste and smell organs rather than silk-producing structures.^[69] The nervous system of tarantulas is typical of arachnids, featuring a centralized, ganglionated ventral nerve cord that runs along the body, with segmental ganglia coordinating leg movements and sensory inputs. The brain, or supraesophageal ganglion, located in the prosoma dorsal to the esophagus, integrates visual, mechanosensory, and chemosensory information, while circumesophageal connectives link it to the subesophageal ganglion and the ventral cord's posterior ganglia. This architecture supports basic associative learning, including habituation, where repeated exposure to non-threatening stimuli, such as vibrations, leads to decreased responsiveness over time, allowing tarantulas to filter out irrelevant environmental noise.^[70]^[71] Tarantulas lack dedicated electroreceptors, relying instead on substrate vibrations for prey localization rather than electrical fields. Their sensory limitations, particularly the rudimentary nature of vision, underscore a primary dependence on tactile and chemical modalities for survival, enabling effective foraging and predator avoidance in low-light burrows or leaf litter habitats.^[72]

Respiratory and Circulatory Systems

Tarantulas, as mygalomorph spiders, possess two pairs of book lungs located ventrally in the abdomen—one anterior pair and one posterior pair—that serve as the primary respiratory organs for gas exchange. These structures consist of numerous thin, stacked lamellae resembling the pages of a book, which maximize the surface area for the passive diffusion of oxygen from the air into the surrounding hemolymph. Air enters the book lungs through slit-like openings called spiracles, covered by opercula, and oxygen diffuses across the moist lamellae into the hemolymph channels without active ventilation.^[73]^[74] The low metabolic rate of tarantulas supports this reliance on slow, diffusive gas exchange, enabling adequate oxygenation even with limited airflow. Hemocyanin, the copper-based respiratory pigment in the hemolymph, enhances hypoxia tolerance by binding oxygen with high affinity under low-oxygen conditions, appearing blue when oxygenated. This adaptation is particularly beneficial in enclosed microhabitats, where oxygen levels may fluctuate. In some tarantula species, supplemental tubular tracheae extend from the anterior book lungs to deliver air directly to tissues, augmenting book lung function.^[75]^[76]^[77] The circulatory system of tarantulas is open, lacking a network of capillaries, with hemolymph freely bathing organs and tissues for nutrient distribution, oxygen delivery, and waste removal. A dorsal tubular heart, situated in the abdomen, pumps hemolymph anteriorly through a main aorta and branching arteries, after which it percolates through the body cavity before returning via open sinuses and lung veins. Hemolymph enters the heart through paired ostia—lateral openings equipped with one-way valves—that allow inflow during diastolic relaxation. The hemolymph's hemocyanin component facilitates oxygen transport from the book lungs throughout the body.^[78]31960-X/fulltext) In burrowing tarantula species, such as those in arid or soil-rich habitats, the book lungs exhibit enhanced lamellar density for more efficient gas exchange in oxygen-poor burrow environments, supporting prolonged inactivity. Molting temporarily disrupts both systems, as the shedding of the exoskeleton exposes and reforms the book lung lamellae and heart pericardium, reducing oxygen capacity and requiring several days of immobility for recovery.^[75]^[79]

Reproduction and Life Cycle

Mating and Reproduction

Tarantula mating begins with elaborate courtship behaviors performed by mature males, who locate receptive females primarily through pheromones released in silk trails or draglines. Upon encountering a female, the male initiates courtship by rapidly tapping his pedipalps and front legs on the substrate—a behavior known as drumming or stridulation—which produces vibrations to signal his presence, species identity, and quality without direct contact.^[80] This cautious approach allows the male to assess the female's receptivity; aggressive responses, such as charging or leg-waving, may prompt retreat. In some species, males exhibit additional displays like push-ups or body oscillations to further entice the female. Courtship rituals can last from 30 minutes to several hours, depending on the species and female's response, emphasizing the high risk of predation during this phase.^[81] Once courtship succeeds, the male deposits sperm onto a specialized silk web, which he constructs away from the female to avoid immediate danger. He then draws the sperm into bulbous structures at the tips of his pedipalps, known as emboli, using capillary action. During copulation, the pair assumes a face-to-face position with bodies elevated, and the male inserts each embolus alternately into the female's epigyne (genital opening) one to five times, transferring sperm packets directly to her spermathecae for storage.^[3]^[80] This process enables internal fertilization and allows females to store viable sperm for months, facilitating delayed oviposition when conditions are optimal. Males often possess tibial hooks or spurs on their front legs, a form of sexual dimorphism, to clasp the female's fangs and prevent bites during insertion.^[82] Multiple matings are possible for both sexes; males can impregnate several females per reproductive season using a single sperm charge, while females may mate with multiple males to increase genetic diversity, though some species exhibit monogamous tendencies.^[80]^[81] Post-mating, sexual cannibalism frequently occurs, with the female consuming the male, often starting head-first; this behavior provides nutritional benefits to the female and may enhance offspring survival, though its frequency varies by species and context, reported as low in some wild populations but higher in captivity.^[80]^[82] To escape, successful males break contact abruptly and flee, sometimes using specialized leg structures for leverage. Following fertilization, the female produces a silk cocoon containing 100 to 1,000 eggs, depending on species size and environmental factors, which she seals and aggressively guards in her burrow for 6 to 9 weeks to protect against predators and maintain optimal humidity.^[3]^[82]

Growth and Development

Tarantula eggs, typically numbering 100 to 1,000 depending on the species, hatch into spiderlings after an incubation period of about 6 to 9 weeks within the guarded egg sac.^[3] These spiderlings emerge as first-instar juveniles, which are miniature versions of the adults but lacking full sexual differentiation. To reach maturity, tarantulas undergo 7 to 12 molts, with the exact number varying by species, sex, and environmental factors; for example, in Brachypelma albopilosum, juveniles pass through 8 to 12 molts from the first instar to adulthood.^[83] Each instar stage can last from several weeks in early juveniles to over a year in later stages, allowing gradual increases in size and development of features like urticating hairs or fangs.^[84] The molting process, known as ecdysis, is hormonally regulated primarily by ecdysteroids, which trigger the formation of a new exoskeleton beneath the old one.^[83] Prior to molting, the tarantula becomes inactive, ceases feeding, and secretes enzymes to separate the old cuticle; it then flips onto its back or side to shed the exuviae, a process that can take 15 minutes to several hours.^[85] During this vulnerable period, the newly emerged soft cuticle provides no protection against predators or injury, making the spider highly susceptible until the exoskeleton hardens over the following days. Growth occurs as the fresh, expandable cuticle absorbs water and expands before sclerotizing, enabling the tarantula to increase in size by up to 50% per molt in early instars.^[86] Following hatching, female tarantulas provide maternal care by guarding the egg sac and burrow, maintaining it under her body to protect against threats.^[87] Spiderlings remain communally in the maternal burrow for several weeks, undergoing their first molt while benefiting from this protection; in species like Brachypelma vagans, they then disperse en masse, often forming a column of hundreds as they leave to establish individual burrows or webs.^[88] This subsocial phase typically ends after 2 to 8 weeks in the wild, after which the spiderlings become independent and face solitary lives. Sexual maturity is achieved after the final molt, with males generally maturing faster than females; in many Theraphosidae species, males reach adulthood in 1 to 3 years, while females take 3 to 7 years or longer.^[89] The terminal molt in males develops their pedipalps into bulbous sex organs for sperm transfer, marking the end of their growth phase, whereas females may continue molting post-maturity to further increase size.^[90] Juvenile mortality in tarantulas is very high in the wild, primarily due to predation by birds, reptiles, and invertebrates, as well as intraspecific cannibalism among siblings in crowded burrows.^[83] Cannibalism is particularly prevalent during resource scarcity, reducing competition but contributing significantly to early instar losses.

Taxonomy and Diversity

Classification and Subfamilies

Tarantulas belong to the family Theraphosidae within the order Araneae, suborder Opistothelae, infraorder Mygalomorphae, and superfamily Theraphosoidea.^[91] This placement reflects their primitive arachnid characteristics, distinguishing them from more derived araneomorph spiders. The family Theraphosidae was established by Tamerlan Thorell in 1869, encompassing large, often hairy mygalomorph spiders distributed primarily in tropical and subtropical regions worldwide.^[91] A key diagnostic trait of Theraphosidae, shared with other mygalomorphs, is the parallel orientation of the chelicerae, which point downward and move vertically rather than opposing each other as in araneomorphs; this structure supports powerful downward strikes for prey capture and burrowing.^[92] The family is divided into approximately 13-14 subfamilies, with classifications often based on ecological habits such as burrowing (terrestrial) versus climbing (arboreal).^[93] Prominent subfamilies include Theraphosinae (predominantly terrestrial, New World species with stridulating organs), Aviculariinae (arboreal, Old World and Neotropical species lacking urticating hairs), and Harpactirinae (African "baboon spiders," fast-moving terrestrial forms).^[91] Other subfamilies, such as Eumenophorinae, Ischnocolinae, and Selenocosmiinae, exhibit varied morphological and behavioral adaptations tied to their habitats.^[93] Molecular phylogenetic studies since 2010 have significantly revised Theraphosidae groupings, incorporating transcriptome and multi-locus data to resolve deep relationships and challenge morphology-based classifications.^[94] For instance, analyses have confirmed the monophyly of Harpactirinae within African theraphosids and revealed non-monophyly in some genera, prompting subfamily realignments based on genetic evidence rather than solely on burrowing or arboreal traits.^[95] These updates, including phylogenomic reconstructions, indicate a Gondwanan origin for the family with subsequent dispersals, enhancing understanding of evolutionary divergences.^[96] As of November 2025, Theraphosidae comprises 1,181 species across 186 genera, reflecting ongoing taxonomic discoveries and revisions.^[2] This diversity underscores the family's ecological versatility, from fossorial burrowers to arboreal web-builders, though detailed genus-level variations are addressed elsewhere.^[91]

Genera and Species Diversity

The family Theraphosidae encompasses 1,181 valid species distributed across 186 genera worldwide, representing the most diverse group of mygalomorph spiders.^[2] This species richness reflects extensive taxonomic revisions and ongoing discoveries, with the majority of genera containing relatively few species while a handful host dozens.^[1] Several genera exemplify the family's ecological and morphological variety. The genus Avicularia, primarily arboreal and native to tropical South America, includes 12 recognized species adapted to tree-dwelling lifestyles with slender bodies and fast movements.^[91] In contrast, Grammostola comprises 20 species from temperate South America, known for their docile temperament and popularity as pets due to robust builds and burrowing habits.^[91] The Asian genus Poecilotheria features 15 species, often aggressive arboreal hunters with striking banded patterns, slings (young) of which are frequently traded as "slingshots" in the hobbyist market.^[91] North America's Aphonopelma stands out with 54 species, including long-lived individuals—females can survive over 30 years in captivity—highlighting the genus's adaptation to arid environments and slow maturation.^[91] Diversity patterns within Theraphosidae are pronounced, with over 50% of species concentrated in the Neotropics, particularly in tropical forests of South and Central America, where habitat complexity supports high endemism and speciation rates.^[97] Island regions like Madagascar exhibit elevated endemism, hosting unique genera such as Monocentropus with species restricted to specific forest habitats, underscoring the role of isolation in driving localized diversity.^[93] In the pet trade, species like Brachypelma smithi (Mexican redknee tarantula, one of 9 in its genus) are staples due to their vibrant orange-red leg markings and calm demeanor, but wild collection has raised conservation concerns, leading to its listing under CITES Appendix II to regulate international trade and mitigate population declines from habitat loss in Mexico.^[91]^[34] Morphological diversity spans body sizes from dwarf forms with leg spans under 3 cm, such as certain Cyriopagopus species, to giants like Theraphosa blondi exceeding 30 cm in leg span, enabling varied predatory strategies from ambush to active hunting.^[98] Color variations, including iridescent blues in Chilobrachys or cryptic browns in ground-dwellers, serve functions in camouflage against predators and visual signaling during mating displays.^[99] Estimates suggest thousands of undescribed Theraphosidae species exist, potentially doubling current known diversity, based on molecular surveys revealing cryptic lineages in understudied regions like Australia and the Neotropics.^[100]^[1]

Recent Discoveries

In 2023, researchers described a new tarantula species, Chilobrachys natanicharum, from the mangrove forests of southern Thailand, notable for its striking iridescent blue-violet coloration on the legs and cephalothorax, along with distinctive black banding on the legs of males.^[101] This fossorial species, which inhabits tree hollows and burrows, represents a rare example of structural coloration in theraphosids, achieved through light interference rather than pigments.^[101] The discovery was made using morphological examination and molecular analysis, including DNA barcoding of the COI gene, highlighting its distinction from other Chilobrachys species.^[101] In 2025, four new tarantula species were identified from the Arabian Peninsula and the Horn of Africa, forming a novel genus Satyrex within the subfamily Harpactirinae: Satyrex ferox, Satyrex arabicus, Satyrex speciosus, and Satyrex somaliensis.^[93] These species are characterized by exceptionally long male palpal bulbs—the longest recorded among all mygalomorph spiders—measuring up to 15 mm in some cases, an adaptation hypothesized to allow safer mating by enabling males to inseminate females from a distance and reduce the risk of sexual cannibalism in these aggressive species.^[93] The descriptions relied on integrative taxonomy, combining detailed morphological studies of genitalia and setae with phylogenetic analysis based on mitochondrial and nuclear DNA markers.^[93] Also in 2024, a new species, Aphonopelma jacobii, was documented from the remote Chiricahua Mountains in southeastern Arizona, USA, where it occupies high-elevation oak woodlands in the Madrean Sky Islands.^[102] This small, gray-black tarantula with reddish abdominal hairs faces immediate extinction risks from habitat fragmentation, climate change-induced warming, and aridification, which could render its narrow range uninhabitable within decades.^[102] Identification involved comparative morphology, such as leg spination patterns, and genetic sequencing to confirm its separation from related Aphonopelma taxa.^[102] These recent additions, alongside ongoing taxonomic revisions, contribute to the current total of 1,181 described tarantula species worldwide.^[2] They underscore the importance of targeted surveys in biodiverse yet understudied regions, such as the Middle East and arid southwestern North America, to document and conserve theraphosid diversity before habitat loss accelerates extinctions.^[103]

Evolutionary History

Fossil Record

The fossil record of tarantulas, belonging to the family Theraphosidae within the mygalomorph spiders, is sparse compared to other arachnid groups, reflecting the challenges of preserving their soft-bodied structures. The earliest known mygalomorph ancestors date to the Carboniferous period, approximately 300 million years ago (mya), with specimens such as Arthrolycosa wolterbeeki discovered in late Carboniferous (Moscovian stage) deposits from the Piesberg quarry in Germany.^[104] These primitive forms, preserved as compressions in coal-bearing sediments, exhibit basic spider morphology including segmented legs and a tuberculate opisthosoma, but lack advanced features like modern spinnerets, indicating an early stage in arachnid evolution.^[105] Other Carboniferous examples, such as Arthrolycosa antiqua from Mazon Creek, Illinois, USA, further illustrate this ancient lineage in coal deposits across Euramerica.^[106] Definitive theraphosid fossils are rare and primarily known from amber inclusions, with the oldest confirmed specimen being Protertheraphosa spinipes from mid-Cretaceous Burmese amber, dated to about 100 mya.^[107] This large tarantula, with a leg span estimated at over 5 cm, shows preserved hairy legs and spines, providing evidence of early theraphosid diversification in Gondwanan regions during the Cretaceous..pdf) Later Cenozoic records include mygalomorphs in Eocene Baltic amber (around 44 mya), with forms displaying setose legs, though specific family assignments remain tentative due to incomplete preservation.^[106] Key Miocene specimens from Dominican and Chiapas ambers highlight exceptional preservation, including urticating hairs on the abdomen and legs—defensive structures characteristic of modern tarantulas.^[108] Preservation of tarantulas is hindered by their soft exoskeletons and terrestrial habits, resulting mostly in amber-trapped inclusions or faint impressions in sedimentary rocks, with rare body fossils post-Cretaceous.^[109] This fragmentary record reveals gaps, particularly between the Cretaceous and Miocene, but underscores ancient distributions across Laurasia and Gondwana, informing broader evolutionary patterns. No fossils represent complete modern genera.^[106]

Evolutionary Adaptations

Tarantulas belong to the infraorder Mygalomorphae, a basal lineage of spiders that diverged from the more derived Araneomorphae approximately 300 million years ago during the Carboniferous period.^[110] This ancient split is evidenced by phylogenomic analyses incorporating fossil-calibrated divergence times, highlighting the mygalomorphs' retention of primitive chelicerae that articulate paraxially and strike downward, in contrast to the transverse orientation in araneomorphs.^[111] These chelicerae reflect an early evolutionary condition suited to subduing prey through direct stabbing motions, underscoring the mygalomorphs' position as a foundational group in spider phylogeny. A key respiratory adaptation in tarantulas and other mygalomorphs is the presence of book lungs, which evolved from the book gills of aquatic arthropod ancestors as spiders transitioned to terrestrial life.^[112] This single evolutionary origin in a common arachnid ancestor facilitated efficient gas exchange in air, with the lamellate structure invaginating from the body wall to form stacked air-filled pages.^[113] In tarantulas, these book lungs persist as the primary respiratory organs, enabling survival in diverse microhabitats from burrows to foliage. Defensive adaptations in tarantulas include urticating hairs, barbed setae unique to New World species in the family Theraphosidae, which evolved independently in multiple lineages for predator deterrence.^[61] These hairs, produced from specialized abdominal areas, are flicked or rubbed off to irritate attackers, with morphological types varying by subfamily—such as type I in Aviculariinae and types II–VI in Theraphosinae—enhancing survival without relying solely on venom.^[114] The diversification of tarantulas was profoundly influenced by the breakup of the Gondwanan supercontinent, which promoted radiation across the Southern Hemisphere beginning in the mid-Cretaceous around 120 million years ago.^[115] Ancestral theraphosids originated in regions spanning modern Africa and South America, with vicariance events driving isolation and speciation in South America, Africa, and Australia, while later dispersals reached Asia.^[116] Post-Cretaceous environmental shifts, including the rise of angiosperm forests, facilitated multiple independent acquisitions of arboreal habits, allowing tarantulas to exploit tree-dwelling niches in tropical ecosystems.^[39] Recent phylogenetic studies have revealed rapid evolution in tarantula genitalia, particularly in the newly described genus Satyrex, where males exhibit exaggeratedly elongated palpal bulbs—reaching up to 5 cm in S. ferox—likely as an adaptation to maintain distance from cannibalistic females during mating.^[117] This extreme sexual dimorphism, with palps nearly four times the carapace length, represents a derived strategy to enhance male survival in highly aggressive species, diverging from the typical 1.5–2 times ratio in other theraphosids. Tarantula venom has evolved from simpler paralytic components in basal mygalomorphs to more complex mixtures dominated by linear and disulfide-rich peptides, reflecting adaptations for prey immobilization over broad-spectrum toxicity.^[118] In contrast to the cystine-knot toxins prevalent in araneomorph venoms, mygalomorph peptides like those in Theraphosidae target ion channels with lower mammalian potency, resulting in low human toxicity characterized by localized pain rather than systemic effects. This derived reduction in neurotoxicity aligns with tarantulas' reliance on size and urticating hairs for defense, prioritizing hunting efficacy against invertebrates.^[119]

References

[1]
What does the history of Theraphosidae systematics tell us about the ...
This one family comprises over one-third of described mygalomorph diversity with over 1,100 valid species (as of 16 April 2024; World Spider Catalog, 2024).Abstract · Introduction · Methods · Results & discussion
[2]
Tarantulas | National Geographic
Common Name: Tarantulas ; Scientific Name: Theraphosidae ; Diet: Carnivore ; Average Life Span In The Wild: Up to 30 years ; Size: 4.75 inches long; leg span: up to ...<|control11|><|separator|>
[3]
The Tarantula (Family Theraphosidae)
Identification: Tarantulas are characterized by having 2 pairs of book lungs, clearly visible on the ventral surface of the abdomen and notable for their large ...
[4]
Tarantula Spider Toxicity - StatPearls - NCBI Bookshelf - NIH
There are over 900 different species that comprise the family Theraphosidae within the Mygolamorphae suborder, which itself includes over 2500 species of ...
[5]
Learn About the Tarantulas Family Theraphosidae - ThoughtCo
Oct 6, 2019 · People recognize tarantulas by their enormous size, relative to other spiders, and by their conspicuously hairy bodies and legs.
[6]
A new species of Southeast Asian dwarf tarantula in the genus ...
Jul 22, 2025 · Tarantulas belong to the family Theraphosidae Thorell, 1869, a dominant group within the suborder Mygalomorphae comprising 172 genera and 1,132 ...
[7]
Largest spider | Guinness World Records
The goliath bird-eating tarantula (Theraphosa blondi) is the largest by mass, with a leg span up to 30 cm, and the heaviest spider.
[8]
Tarantula | San Diego Zoo Animals & Plants
Tarantulas are nocturnal hunters, preying on a variety of insects, other spiders, and small lizards, snakes, and frogs. They rely on ambush and pursuit to catch ...About · Habitat And Diet · Family Life
[9]
Why Would You Want a Pet Tarantula? - Terminix
Jul 10, 2020 · 4. Docile nature. Though their large, furry bodies may suggest otherwise, tarantulas are considered to be calm and quiet pets. Most species of ...Missing: source | Show results with:source
[10]
Tarantulas - the truth behind their evil image - The Australian Museum
Occurring every summer for three hundred years, this disease was thought to be caused by the bite of a large, hairy Wolf Spider (Lycosa tarantula), which became ...<|separator|>
[11]
TARANTULA Definition & Meaning - Merriam-Webster
: a European wolf spider (Lycosa tarantula) formerly held to be the cause of tarantism ... Etymology. Medieval Latin, from Old Italian tarantola, from ...
[12]
Tarantula - Etymology, Origin & Meaning
Originating from 1560s Italian "tarantola" (from Taranto, Italy), "tarantula" means a wolf spider, linked to the city's frequent spider presence.
[13]
tarantula - Wiktionary, the free dictionary
From Medieval Latin tarantula, from Old Italian tarantola, from Taranto (“seaport in southern Italy”), from Latin Tarentum (“Latin name of the town”), from ...English · Etymology · Dutch · Finnish
[14]
Theraphosidae - an Overview on Tarantula spiders - birdspidersCH
This family of spiders is one of the most well-known and diverse families of arachnids, and it contains some of the largest spider species in the world.
[15]
Theraphosa - Wiktionary, the free dictionary
Etymology. By surface analysis, Ancient Greek θήρᾱ (thḗrā, “hunting, a hunt or chase”) +‎ Ancient Greek φώς (phṓs, “man”) +‎ -a f . Compare English huntsman. ...
[16]
THERAPHOSID Definition & Meaning - Merriam-Webster
Word History. Etymology. from the stem of New Latin Theraphosidae, family name, from Theraphosa, a genus (from Greek thēráphion "a kind of insect" —from thḗr ...
[17]
[PDF] Etymological origins of the generic names of Mexican tarantulas ...
This paper looks at the etymology of the genera in of Mexican tarantulas (family Theraphosidae) from an historic perspective, pointing out nomenclatural details ...
[18]
Aphonopelma - Wiktionary, the free dictionary
Aphonopelma eutylenum. Etymology. a- (negating prefix) +‎ phono- (“noise”) +‎ Ancient Greek πέλμᾰ n (pélmă, “sole (of the foot)”), literally “soundless-soled” ...
[19]
Spider Anatomy - Pedipalps - University of Kentucky
Nov 19, 2009 · SPIDER ANATOMY. All spiders have 8 legs, 2 body parts (cephalothorax and abdomen), fang-like "chelicerae," and antenna-like "pedipalps.
[20]
[PDF] Identification of CITES-listed Tarantulas
Urticating hairs Fine barbed hairs located on the abdomen of most New World tarantulas, used as a defense mechanism against predation. Ventral The underside.
[21]
Brazilian Theraphosidae: a toxicological point of view - PMC
T. apophysis (Tinter 1991), known as pink foot goliath tarantula, is another giant tarantula belonging to Theraphosa genus, with leg span up to 30 cm.Theraphosa Blondi · Acanthoscurria Natalensis · Lasiodora Sp
[22]
ENY201/MG206: Spiders - University of Florida
Feb 15, 2022 · b) The pinktoe tarantula can sometimes be found in South Florida. c) The aggressive cobalt blue should only be kept by experienced keepers.
[23]
The ultrastructure of the book lungs of the Italian trap-door spider ...
The respiratory system of Cteniza sp. consists of two pairs of well-developed book lungs, which is considered indicative of primitive spiders. The general ...
[24]
A new electric-blue tarantula species of the genus Chilobrachys ...
Sep 18, 2023 · Tarantulas possess a stridulation organ on their prolateral maxillae, consisting of an oval patch of modified setae used to produce sound by ...
[25]
https://doi.org/10.7717/peerj.5751
[26]
https://doi.org/10.11646/zootaxa.3673.1.1
[27]
https://doi.org/10.1098/rspb.2020.1688
[28]
World Spider Catalog: NMBE
World Spider Catalog Version 26. Currently 53'528 accepted species included. Introduction. Submit your latest taxonomic publication to wsc(at)nmbe.ch.Search · Introduction · Families · Archive
[29]
Biodiversity of the Huautla Cave System, Oaxaca, Mexico - MDPI
Mexico holds the second highest diversity of species of tarantulas worldwide behind Brazil, and Mexico is the richest country in tarantula cave species.
[30]
(PDF) The Mexican Redrump, Brachypelma vagans (Araneae
vagans has been reported as establishing populations outside the native range in four locations (Edwards & Hibbard 1999 , 2003Reichling 2000;Machkour-M'Rabet et ...
[31]
A molecular approach to understand the riddle of the invasive ...
Brachypelma vagans, a successfully invasive species of tarantula. · Tarantula specie exhibits high genetic diversity both in native and invasive range.
[32]
(PDF) Tarantulas and Their Habitats - ResearchGate
New World Theraphosidae inhabit a great variety of habitats from deserts and semi-deserts, grasslands to forests of all types.
[33]
Aphonopelma chalcodes | INFORMATION - Animal Diversity Web
Desert tarantulas, Aphonopelma chalcodes, are common throughout the Southwestern United States, especially Arizona, New Mexico, and Southern California.
[34]
Species conservation profiles of tarantula spiders (Araneae ...
These spiders are nocturnal predators that wait near the entrance of their refuge from dusk and into the night to feed primarily on ground-dwelling arthropods ( ...
[35]
Species conservation profiles of tarantula spiders (Araneae ...
Nov 8, 2019 · These spiders are nocturnal predators that wait near the entrance of their refuge from dusk and into the night to feed primarily on ground- ...
[36]
Tarantula Reproductive Period & Thermal Preferences
Our results show that the reproductive period is constrained by thermal preferences, dictating when males can start their wandering life to mate.
[37]
Arachnids - Amazon Aid
Spiders and arachnids make up to 5-10% of all Arthropods in rainforest canopies, represented most famously by the beautiful, bright Greenbottle Blue Tarantula ...
[38]
New electric-blue tarantula species is first found in Thailand ...
Oct 9, 2023 · Habitat destruction and hunting have severely impacted local tarantula populations in Thailand. As a result, all Theraphosidae species in ...Missing: threats | Show results with:threats
[39]
Sonoran Desert Fact Sheet - Desert Blonde Tarantula
Habitat and Range. Desert blonde tarantulas can be found within the deserts of Arizona, New Mexico, Southern California, and Mexico. They are well suited to ...
[40]
The evolution of coloration and opsins in tarantulas - PMC - NIH
Moreover, it is well appreciated that certain tarantula species exhibit sexual dimorphism, including age-related dimorphism across several genera (e.g. ...<|separator|>
[41]
[PDF] Supplemental feeding alters foraging behaviors of tarantulas in their ...
In their natural environments, burrow-dwelling tarantulas are typically crepuscular/nocturnal with foraging behavior that starts as the sun sets and extends ...
[42]
Goliath bird-eating tarantula - National Zoo
The Goliath bird-eating tarantula is the world's biggest, with a body up to 4.75 inches and a leg span up to 11 inches. It lives in South American rainforests ...
[43]
Characterisation of protein families in spider digestive fluids ... - NIH
Aug 10, 2017 · The use of an array of digestive enzymes facilitates the consumption of the prey by liquefying its tissues before ingesting it. Spiders are one ...
[44]
Record breaking achievements by spiders and the scientists who ...
Oct 31, 2017 · ... leg span (up to 30 cm; Jäger, 2001; Fig. 3B). With a total body ... Tarantula peptide inhibits atrial fibrillation. Nature. 2001;409 ...<|control11|><|separator|>
[45]
Gooty Sapphire Tarantula Animal Facts - Poecilotheria metallica
Scientific Name: Poecilotheria metallica ; Prey: Flying insects, crickets ; Main Prey: Flying insects ; Name Of Young: spiderlings ; Group Behavior. Subsocial.
[46]
Invertebrates - White Sands National Park (U.S. National Park Service)
Jan 20, 2022 · Tarantulas make their homes in burrows and crevices. They will lie in wait and ambush instead of using a web to ensnare their prey.<|control11|><|separator|>
[47]
Tarantulas | National Wildlife Federation
Tarantulas are large, long-lived arachnids that can shoot urticating hairs. They are found in the Southwest US, and are burrowing species. They are fierce ...Missing: scientific | Show results with:scientific
[48]
Effect of temperature on leg kinematics in sprinting tarantulas ...
At these two joints, extension results from hydraulic pressure generated by muscles that compress the prosoma (or cephalothorax), causing hemolymph to flow out ...
[49]
Neurons and a sensory organ in the pedipalps of male spiders ...
Sep 22, 2017 · Before sperm release during mating, spider males have to charge their pedipalps. They transfer sperm from the production site (testes in ...Missing: tarantula | Show results with:tarantula
[50]
Chelicerae - an overview | ScienceDirect Topics
The chelicerae of mygalomorphs are oriented parallel to the long axis of the body and move parallel to one another in a vertical plane. These spiders strike ...
[51]
Mygalomorphae; Theraphosidae) - PMC - PubMed Central
... (chelicerae are in a vertical position opposing each other) (reviewed in e.g., Foelix 2011). As the chelicerae of Mesothelae also run in parallel to each ...<|separator|>
[52]
Slit sense organ distribution on legs of two spider species
We show that both species have a similar distribution of slit sense organs, with small isolated slits occurring in consistent lines parallel to the long axis ...
[53]
Tarantulas shoot silk from feet - EarthSky
May 17, 2011 · While they don't spin typical webs as other spiders do, they do make silk and use it to line or protect their burrows. Intrigued by a scientific ...Missing: arboreal pads
[54]
Tarantulas (Araneae: Theraphosidae) use different adhesive pads ...
Nov 4, 2015 · Adhesive setae enable tarantulas to climb on smooth surfaces, e.g. on leaves and on vertical glass plates (Homann, 1957; Wolff and Gorb, 2015; ...
[55]
Tarantula (U.S. National Park Service)
Apr 26, 2017 · Tarantulas have many natural predators including larger lizards, snakes, and birds. However, the most ferocious is the tarantula hawk, a large, ...
[56]
Tarantula Fact Sheet - Arizona-Sonora Desert Museum
Male tarantulas live 10 to 12 years. Females can live twice as long. Size. In the Sonoran Desert, tarantulas grow to a length of 3 to 4 inches (70-100 ...
[57]
Wildly Successful: The Roadrunner - Connecticut's Beardsley Zoo
Sep 7, 2022 · Capturing and consuming venomous prey including centipedes, scorpions, tarantulas, and the feared Tarantula Hawk Wasp, the Roadrunner is ...
[58]
Tarantula Sightings in Utah: Everything You Need to Know
Oct 23, 2024 · Utah's tarantulas are hunted by many local predators, including coyotes, skunks, and fearsome tarantula hawk wasps. Even some snakes and lizards ...
[59]
https://www.tandfonline.com/doi/full/10.1080/00222933.2024.2382404
[60]
Endangered Species Status for Five Poecilotheria Tarantula ...
Jul 31, 2018 · They are long-lived, have delayed sexual maturity, and most are habitat specialists that are extremely sedentary. They also have poor dispersal ...<|separator|>
[61]
Urticating setae of tarantulas (Araneae: Theraphosidae)
Nov 11, 2019 · Urticating setae are modified, barbed setae on tarantula abdomens or pedipalps, used as a defense mechanism against predators and intruders.
[62]
Setal entanglement: an undescribed method of stridulation by a ...
Setal entanglement: an undescribed method of stridulation by a neotropical tarantula (Araneae: Theraphosidae) ... The biology of a giant spider: Theraphosa ...
[63]
https://doi.org/10.1186/s12864-017-3987-9
[64]
https://doi.org/10.1038/s41598-023-29828-x
[65]
Spider structure - The Australian Museum
The external and internal structures of spiders, including skin, muscles, breathing system, digestive tract and reproductive organs.
[66]
https://doi.org/10.1186/s12864-016-3048-9
[67]
https://doi.org/10.1002/ece3.5382
[68]
Molecular Evolution of Spider Vision: New Opportunities, Familiar ...
The four eye pairs can be divided into two fundamental types: the AM eyes are called “principal” eyes, whereas the AL, PM, and PL eyes are all “secondary” eyes.
[69]
Silk secretion from tarantula feet revisited: alleged spigots are ...
Apr 1, 2012 · Our conclusion is that the ribbed hairs are chemoreceptors, not spigots. Observations of live tarantulas clinging inverted to glass coverslips ...
[70]
Fine Structural Analysis of the Central Nervous System in the Spider ...
Mar 23, 2007 · The CNS of the spider, Achaearanea tepidariorum, consists of a dorsal brain or supraesophageal ganglion and circumesophageal connectives joining ...Missing: tarantula | Show results with:tarantula
[71]
Extended spider cognition - PMC - PubMed Central - NIH
Feb 7, 2017 · Spiders do not seem to be cognitively limited, displaying a large diversity of learning processes, from habituation to contextual learning, including a sense ...
[72]
Electric Fields Elicit Ballooning in Spiders - ScienceDirect.com
Jul 23, 2018 · We test the hypothesis that electric fields (e-fields) commensurate with the APG can be detected by spiders and are sufficient to stimulate ballooning.Missing: absence | Show results with:absence
[73]
ADAPTATIONS OF RESPIRATORY SYSTEMS OF SPIDERS
Some orders' have only book lungs: four pairs in scorpions, two pairs in Uropygi and orthognath spiders (the mygalomorph “tarantulas” of American usage), one ...
[74]
[PDF] AN ATLAS OF BOOK LUNG FINE STRUCTURE IN THE ORDER ...
Dec 24, 2008 · Book lungs are the primary organs for respiration in arachnids, presumed to have evolved as a consequence of terrestria- lization in the stem ...
[75]
Book lung function in arachnids
Arachnids were among the first animals to conquer the land, and their typical respiratory or- gans, the book lungs, possibly derive from the book gills of ...Missing: system | Show results with:system
[76]
Respiratory Function of the Hemocyanins - jstor
oxygen affinity, hemocyanins can be highly oxygenated at the site of gas exchange with ... noted for their tolerance of hypoxia, the striking exception ...
[77]
The respiratory complementarity of spider book lung and tracheal ...
Like most spiders, members of the orb-weaving family Uloboridae have a dual respiratory system. Book lungs oxygenate the hemolymph and tracheae carry oxygen ...
[78]
The Open Circulatory System of Spiders (Eurypelma californicum ...
The spider's open circulatory system includes the heart, pericardium, arterial and open venous systems, and lung veins. Hemolymph enters the heart, then is ...
[79]
Respiratory Function of the Hemocyanins1
Hemocyanins are important for respiratory function, can be highly oxygenated, but their oxygen transport is limited by environmental changes and blood pH.
[80]
Animal Sex: How Tarantulas Do It | Live Science
Apr 2, 2016 · Here's a look at tarantula mating, which involves charging their pedipalps with sperm, spinning a sperm web, dancing and fang clasping.
[81]
Mating system in the tarantula spider Eupalaestrus weijenberghi ...
Females mated once: five females mated at the first attempt, eight initially rejected males and copulated in subsequent attempts. Half of the males did not ...
[82]
Eaten, Crushed or Starved; Male Tarantulas Trade Their Life to ...
Sep 29, 2023 · After eight years maturing in a burrow, male tarantulas venture out to mate, then die a cruel death.
[83]
[PDF] Notes on Egg-sacs and Spiderlings of Two Species of Grammostola ...
Egg-sac care by the females involved maintaining it under her body (Fig ... Spiderling emergence in the tarantula. Grammostola mollicoma (Ausserer 1875): ...
[84]
Juvenile Development, Ecdysteroids and Hemolymph Level of ...
Feb 6, 2012 · The males can reach maturity in 7–8 years, living only 1 year or less after the last molt, while the females reach maturity in 9–10 years, and ...
[85]
Juvenile Development, Ecdysteroids and Hemolymph Level of ...
Aug 10, 2025 · Theraphosidae family, are largest and longest-lived spiders and females continue to grow and molt over the sexually mature stage is reached.
[86]
Ecdysis - an overview | ScienceDirect Topics
Ecdysis is the term for molting. Owing to their rigid exoskeleton, spiders cannot grow unless they molt. Molting occurs after a new cuticle is formed beneath ...
[87]
Why bugs, tarantulas, and other creatures shed their skin
Apr 29, 2022 · When a young arthropod is ready to grow hormones trigger its skin to begin molting, a process known as ecdysis. ... new, replacement cuticle.
[88]
Silk use and spiderling behavior in the tarantula Brachypelma ...
Silk production by spiderlings of the tarantula Brachypelma vagans was recorded from emergence from the egg sac until at least the beginning of dispersal.
[89]
Brachypelma smithi | INFORMATION - Animal Diversity Web
Males reach sexual maturity at approximately the 20th instar (the stage between molts that comes at about 4 years of age). Females mature 2 to 3 years later ...
[90]
Development, growth and allometry in a cohort of the tarantula ...
Despite that sexual dimorphism in tarantulas is not always evident, some studies showed that males are a little smaller and have longer legs than the females, ...
[91]
Family: Theraphosidae Thorell, 1869 - NMBE - World Spider Catalog
Detailed taxonomic information about the spider families.<|separator|>
[92]
A Reconsideration of the Classification of the Spider Infraorder ... - NIH
Jun 19, 2012 · The families Barychelidae and Theraphosidae (Fig. 2) comprise the highest nominal diversity among mygalomorphs –44 genera with 303 species and ...
[93]
Size matters: a new genus of tarantula with the longest male palps ...
Jul 22, 2025 · Theraphosidae Thorell, 1869 is the largest family of mygalomorph spiders, comprising more than 1,140 extant species in 175 genera and 13 or 14 ...
[94]
Tarantula phylogenomics: A robust phylogeny of deep theraphosid ...
Mygalomorph spiders of the family Theraphosidae, known to the broader public as tarantulas, are among the most recognizable arachnids on earth due to their ...Missing: term | Show results with:term
[95]
Phylogenomic analyses reveal a Gondwanan origin and ... - NIH
Apr 6, 2021 · Mygalomorph spiders from the family Theraphosidae, also known as tarantulas, are also useful models for understanding biogeographic patterns.Biogeographic Analysis · Results · Ancestral Ranges And Ages Of...
[96]
[PDF] A robust phylogeny of multiple tarantula lineages inferred ... - bioRxiv
Jan 8, 2019 · Thus far, the evolutionary history of Theraphosidae remains poorly understood; theraphosid systematics still largely relies on morphological.
[97]
Aphonopelma chalcodes - Wikipedia
As pets. They are popular among beginner tarantula keepers due to their long lifespan (5–10 years for males, up to 30 years for females) and docile nature.
[98]
A new tarantula (Mygalomorphae: Theraphosidae) genus endemic ...
... species in 156 genera (World Spider Catalog 2022). The Neotropics harbor more than a half of the formally described species, most of them included in the ...
[99]
Tarantula facts | Insects & Arachnids - BBC Earth
Tarantulas are spiders from the family Theraphosidae. As of January 2025, there are 1,131 tarantula species across 169 different genera, according to the World ...
[100]
Blue reflectance in tarantulas is evolutionarily conserved despite ...
Nov 27, 2015 · Natural selection on structural color in tarantulas resulted in convergence on color through diverse structural mechanisms.
[101]
Assessing the diversity of Australian tarantulas (Araneae ...
Oct 1, 2023 · We find evidence for there being at least 20 distinct biological species of tarantula in Australia, with the highest species richness in northern Australia.
[102]
A new electric-blue tarantula species of the genus Chilobrachys ...
Sep 18, 2023 · Chilobrachys natanicharum sp. nov. has legs with a unique iridescent blue coloration that is similar to species of Selenocosmiinae such as ...
[103]
Discovery of a new tarantula species from the Madrean Sky Islands ...
Aug 16, 2024 · Aphonopelma jacobii sp. nov. is endemic to the Chiricahua Mountains (Figs 7 , 11 ) in southeastern Arizona where it has been encountered ...
[104]
Tarantula - Wikipedia
Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. As of 2025, more than 1,100 species have been identified, ...List of Theraphosidae species · Lycosa tarantula · Tarantula (disambiguation)
[105]
New tarantula species evolved the longest genitalia to survive mating
Aug 4, 2025 · Four new species of tarantulas have been discovered in the Arabian Peninsula and the Horn of Africa. But these aren't just any tarantulas.
[106]
The first Palaeozoic spider (Arachnida: Araneae) from Germany | PalZ
Jul 16, 2023 · The first Palaeozoic spider from Germany, *Arthrolycosa wolterbeeki*, is from the late Carboniferous, with a tuberculate opisthosoma and ...
[107]
The oldest spider from Germany - Berlin - Museum für Naturkunde
Jul 17, 2023 · This new fossil shows that late Carboniferous spiders also lived in the Piesberg coal forests. Spiders of this age are still extremely rare.
[108]
[PDF] A summary list of fossil spiders and their relatives
Jan 4, 2023 · For an overview see Dunlop & Penney (2012). Spiders remain the single largest fossil group, but our aim here is to offer a summary list of all ...
[109]
Protertheraphosa spinipes Wunderlich & Müller, 2020 - Tarantupedia
New and already described fossil spiders (Araneae) of 20 families in mid and late Cretaceous Burmese Ambers, with notes on spider phylogeny, evolution and ...Missing: tarantula | Show results with:tarantula
[110]
[PDF] A fossil tarantula (Araneae: Theraphosidae) from Miocene Chiapas ...
Of the fifteen currently recognised mygalomorph families, eleven have a fossil record (summarised here), namely: Atypidae, Antrodiaeti- dae, Mecicobothriidae, ...Missing: ancestors | Show results with:ancestors
[111]
(PDF) Fossil spiders - ResearchGate
copal. Until recently, the main source of fossil spiders was Eocene. Baltic amber ... theraphosid. With a carapace length of ca. 0.9 cm and an estimated leg ...
[112]
Phylogenomic analysis, reclassification, and evolution of South ...
With a fossil record extending back to the Middle Triassic (Selden and Gall 1992), they diverged approximately 300 Mya (Ayoub and Hayashi, 2009, Garrison et al.
[113]
Phylogenetic Systematics and Evolution of the Spider Infraorder ...
We present a comprehensive phylogenomic treatment of the spider infraorder Mygalomorphae. We employ 472 loci obtained through anchored hybrid enrichment.
[114]
Book lung development in embryos of the cobweb spider ...
... book lungs of arachnids are derived from aquatic ancestors with book gills like those in the horseshoe crab. The book gills are external and extend ...
[115]
Morphology and evolution of spider book lungs (Araneae)
Sep 17, 2019 · Here, we focus on the fine structure of spider book lungs using standardized terminology and a wider taxon sampling of seven species studied as histological ...
[116]
(PDF) Morphology, evolution and usage of urticating setae by ...
Aug 6, 2025 · Tarantula urticating setae are modified setae located on the abdomen or pedipalps, which represent an effective defensive mechanism against ...
[117]
(PDF) The tangled biogeographic history of tarantulas An African ...
Jun 7, 2023 · The historical biogeography of the Mygalomorph spider family Theraphosidae has been confounded by two conflicting hypotheses –a South American ...
[118]
An African centre of origin rules out the centrifugal model of speciation
Jun 6, 2023 · The historical biogeography of the Mygalomorph spider family Theraphosidae has been confounded by two conflicting hypotheses – a South American ...Abstract · INTRODUCTION · MATERIALS AND METHODS · DISCUSSION
[119]
https://www.pnas.org/doi/10.1073/pnas.1914536117
[120]
Comparative venomics suggests an evolutionary adaption of spider ...
Oct 23, 2025 · A survey of pain in snakebite patients does not support a strong role for defense in the evolution of snake venom composition. Toxins 12 ...
[121]
Structural venomics reveals evolution of a complex venom ... - PNAS
May 12, 2020 · Most spider venoms are dominated by cysteine-rich peptides with a diverse range of pharmacological activities. Some spider venoms contain ...