Elaphe
Elaphe is a genus of non-venomous colubrid snakes in the subfamily Colubrinae, comprising approximately 18 species of medium- to large-sized constrictors commonly known as Old World rat snakes due to their diet primarily consisting of rodents.[1] These snakes are characterized by their robust bodies, keeled scales, and varied coloration patterns that often provide camouflage in their habitats, with adults typically reaching lengths of 1 to 3 meters depending on the species.[2] Native to diverse environments across Eurasia—from southern Europe and the Middle East to East Asia and parts of Southeast Asia—the genus exhibits a wide ecological adaptability, inhabiting forests, grasslands, and rocky areas.[3] The genus Elaphe was established by Leopold Fitzinger in 1833 and originally encompassed a broader range of rat snakes, including species from North America that have since been reclassified into the separate genus Pantherophis based on molecular phylogenetic analyses demonstrating paraphyly in the traditional Elaphe.[4] This taxonomic revision, supported by mitochondrial DNA studies, confines modern Elaphe to Old World taxa, highlighting evolutionary divergences between Palearctic and Nearctic lineages.[5] Most species in the genus are oviparous, laying clutches of 5–20 eggs, though recent discoveries include ovoviviparous forms adapted to high-altitude environments.[5] Notable species include the steppe rat snake (Elaphe dione), widespread in Central Asia, and the Japanese rat snake (Elaphe climacophora), valued in herpetoculture for its docile nature.[2] Elaphe species play significant ecological roles as predators of small mammals and birds, contributing to pest control in agricultural areas, while some face threats from habitat loss and collection for the pet trade, leading to conservation concerns for certain taxa.[3] Their phylogenetic diversity continues to be explored through genomic studies, revealing insights into colubrid evolution and adaptation across temperate and subtropical zones.[1]Taxonomy and classification
Etymology
The genus name Elaphe derives from the Greek elaphē, meaning "deerskin," alluding to the smooth, scaly texture of the snakes' integument that resembles tanned deer hide.[6][7] Austrian zoologist Leopold Fitzinger established the genus Elaphe in 1833, proposing it in the explanatory text to part 3 of Johann Georg Wagler's Beschreibung und Abbildung der Amphibien as a grouping for non-venomous colubrid snakes previously assigned to genera like Coluber.[8][9] Early herpetologists, including Heinrich Boie, advanced the classification through descriptions of relevant species, such as Coluber radiatus (now Coelognathus radiatus) in 1827, which exemplified the traits later formalized under Elaphe.[10] The name Elaphe encountered taxonomic instability due to competing generic designations in the 19th and early 20th centuries, prompting the International Commission on Zoological Nomenclature to exercise its plenary powers under Opinion 490 in 1958; this action validated Elaphe Fitzinger, 1833, as the senior synonym and suppressed obsolete alternatives like Elaphis Jan, 1863, to preserve nomenclatural stability.[11][12]Phylogenetic history
The genus Elaphe was established by Leopold Fitzinger in 1833 within the family Colubridae, initially encompassing Palaearctic rat snakes such as the type species Elaphe parreyssii (now recognized as Elaphe quatuorlineata).[13] During the 19th and early 20th centuries, classifications expanded the genus to include approximately 40 species distributed across temperate and subtropical regions of Eurasia and North America, based primarily on shared morphological features like scalation and dentition.[13] Major taxonomic revisions in the late 20th and early 21st centuries were prompted by molecular phylogenetic studies that demonstrated the paraphyly of Elaphe sensu lato, with New World species forming a distinct evolutionary lineage separate from Old World taxa.[13] These analyses highlighted deep genetic divergences, leading to the transfer of North American species—such as the black ratsnake (Elaphe obsoleta) and cornsnake (Elaphe guttata)—to the resurrected genus Pantherophis between 2002 and 2009, as formalized in herpetological nomenclature standards.[14] Key contributions include the 2002 study by Utiger et al., which sequenced portions of the mitochondrial 12S rRNA (677 bp) and cytochrome c oxidase I (COI; 632–642 bp) genes from 93 individuals across 52 rat snake species, revealing a monophyletic Old World Elaphe clade (including 10 Palaearctic species like E. sauromates) sister to a New World clade encompassing Pantherophis and related genera.[13] This work, supported by morphological evidence such as hemipenal morphology, proposed revalidating genera like Zamenis and Euprepiophis while restricting Elaphe to Old World forms.[13] Concurrently, Burbrink's 2002 phylogeographic analysis of the cornsnake complex, using Bayesian and maximum likelihood methods on cytochrome b sequences from 53 specimens, identified three well-supported geographic lineages (eastern, central, and western) that rejected monophyly of traditional E. guttata subspecies and reinforced the need for Pantherophis as a distinct genus for North American ratsnakes.[15] Mitochondrial DNA data from these studies, combined with morphological traits like vertebral and cranial features, provided robust evidence for the biogeographic split between Old World and New World lineages, with divergence estimates suggesting ancient separation predating the Pleistocene.[13] These findings established the current understanding of Elaphe as a strictly Old World genus, comprising about 17 Eurasian species.[13]Current composition
The genus Elaphe currently includes 18 recognized species of non-venomous colubrid snakes, all native to Eurasia from Europe through Central Asia to East and Southeast Asia.[16] This composition reflects ongoing taxonomic refinements based on molecular phylogenetics, which have excluded several former members, notably North American taxa reclassified into the genus Pantherophis following analyses of mitochondrial DNA that revealed deep divergences; for instance, the black rat snake (Elaphe obsoleta) is now recognized as the Central rat snake (Pantherophis alleghaniensis). Recent additions to the genus have expanded its diversity, including Elaphe xiphodonta and Elaphe ganziensis described in 2021 from China based on morphological and genetic evidence distinguishing them from congeners like Elaphe dione, and Elaphe druzei described in 2023 from the Levant region, supported by phylogenetic analyses showing its sister relationship to Elaphe quatuorlineata.[17][17][5][18] The following table summarizes the recognized species, including common names, primary distribution, and IUCN Red List status (as of 2025). Distributions focus on core ranges, and statuses reflect current assessments where available; many species lack detailed evaluations due to data deficiencies.| Scientific Name | Common Name | Distribution Summary | IUCN Status |
|---|---|---|---|
| Elaphe anomala | Amur rat snake | Russian Far East, Korea, northeast China | LC |
| Elaphe bimaculata | Twin-spotted rat snake | Central and southern China | LC |
| Elaphe cantoris | Cantor's rat snake | Himalayas (India, Nepal, Bhutan) | NT |
| Elaphe carinata | Chinese rat snake | Southern China | LC |
| Elaphe climacophora | Japanese rat snake | Japan, Korea | LC |
| Elaphe dione | Steppe rat snake | Central Asia to Russian Far East | LC |
| Elaphe davidi | Pere David's rat snake | Northern China | LC |
| Elaphe druzei | Levant rat snake | Israel, Lebanon, Syria (mountainous regions) | EN |
| Elaphe ganziensis | Ganzi rat snake | Western Sichuan, China | DD |
| Elaphe hodgsonii | Hodgson's rat snake | Himalayas (Nepal, India, China) | LC |
| Elaphe longissima | Aesculapian snake | Southern and central Europe | LC |
| Elaphe moellendorffi | Moellendorff's rat snake | Southern China, northern Vietnam | LC |
| Elaphe quatuorlineata | Four-lined snake | Southeastern Europe, Middle East | LC |
| Elaphe sauromates | Balkan rat snake | Southeastern Europe, western Asia | LC |
| Elaphe taeniura | Beauty rat snake | Southeast Asia (India to Indonesia) | LC |
| Elaphe urartica | Urartian rat snake | Armenia, Turkey, Iran (highlands) | VU |
| Elaphe xiphodonta | Blade-toothed rat snake | Qinling Mountains, central China | DD |
| Elaphe zoigeensis | Zoige rat snake | Sichuan, China | LC |
Physical description
Morphology
Elaphe species are non-venomous members of the family Colubridae, characterized by a typical rat snake body plan consisting of a cylindrical trunk and an elongated tail that facilitates climbing and locomotion.[19][20] Their scalation includes keeled dorsal scales arranged in 19–27 rows at midbody, which provide traction, and a divided anal plate in most species.[19] The head of Elaphe snakes features a rounded snout adapted for probing, the absence of heat-sensing pits typical of pit vipers, and a prominent loreal scale present between the nasal and preocular scales in the majority of species.[19] In terms of dentition, they possess enlarged rear teeth that aid in grasping prey during constriction, rather than delivering venom, aligning with their opisthoglyphous or aglyphous condition common in colubrids.[19][17] Sexual dimorphism in Elaphe is evident primarily in the male's longer tail relative to body length, which accommodates the hemipenes—paired, eversible organs with spines and folds used in reproduction.[19]Size and variation
Species in the genus Elaphe exhibit a wide range of adult body sizes, typically measuring 1 to over 2 meters in total length, with variation influenced by species and regional populations. Smaller species, such as Elaphe quatuorlineata, attain adult lengths of 1.1 to 1.8 meters, while larger ones like Elaphe carinata commonly reach 1.5 to 2.4 meters, and exceptional individuals may exceed 2.5 meters.[21][22] This size diversity reflects adaptations to diverse habitats across Eurasia, where larger body sizes correlate with predatory efficiency on rodents and birds.[18] Coloration in Elaphe is highly variable but generally features a ground color of brown, gray, or olive, accented by blotches, stripes, or bands that provide camouflage in forested or rocky environments. For instance, many species display dark dorsal blotches outlined in lighter edges, while others show longitudinal stripes; melanistic forms, appearing uniformly black, occur in populations of species like Elaphe dione.[2][23] Geographic variation further diversifies patterns, as seen in Elaphe schrenckii, where the nominate subspecies E. s. schrenckii exhibits a predominantly black body with yellowish bands across much of its range in Russia and China, contrasting with the lighter, more yellowish E. s. anomala in Korean populations.[24] Juveniles often differ markedly from adults through ontogenetic color changes, transitioning from bold, disruptive patterns suited for evasion to more subdued adult hues that aid in thermoregulation or hunting. In Elaphe carinata, hatchlings display prominent brown blotches on a gray background that fade into a darker, more uniform pattern as body weight exceeds approximately 40 grams, typically within the first year.[25] Similarly, blotched juveniles of Elaphe climacophora develop into striped adults, a convergent trait observed across multiple Elaphe species that aligns with shifts in habitat use and predation risks during growth.Sensory adaptations
Elaphe snakes possess well-developed visual capabilities suited to their primarily diurnal activity, enabling them to detect prey and environmental cues at moderate distances. Their eyes feature round pupils, which allow for a broad field of view and adaptation to varying light intensities during daytime foraging. Unlike some nocturnal or ambush predators, Elaphe species rely on motion sensitivity in their retinas to track moving objects effectively, with studies on gray ratsnakes (formerly Elaphe obsoleta) demonstrating orientation toward visual stimuli from prey up to several body lengths away. Color detection is present but limited, primarily sensitive to blues and greens due to the spectral tuning of their cone pigments, though less acute than in mammals; this provides sufficient discrimination for identifying patterned prey against foliage without the full trichromatic range. Olfaction plays a central role in the sensory repertoire of Elaphe, mediated by the vomeronasal organ (Jacobson's organ), which detects non-volatile chemical cues essential for locating prey and navigating habitats. In species such as Pantherophis obsoletus (formerly Elaphe obsoleta), the accessory olfactory bulb exhibits a distinct laminar organization that processes these pheromonal and prey-derived signals, supporting tongue-flicking behaviors to sample airborne and substrate-bound odors. Oral sensory papillae along the tooth rows in Elaphe quadrivirgata further enhance chemosensory detection, containing taste buds with gustatory cells that synapse with nerves to identify chemical profiles of potential food items during close-range assessment. Tactile sensitivity in Elaphe is facilitated by scale sensilla, small mechanoreceptive organs on the head and body scales that respond to substrate vibrations and surface textures, aiding in environmental exploration and prey localization. These dome-shaped structures, observed in related colubrids and referenced in Pantherophis obsoletus (formerly Elaphe obsoleta), concentrate in anterior regions to detect subtle mechanical disturbances without relying on specialized heat-sensing pits, which are absent in this genus as non-pit vipers. Instead, they integrate tactile input with ambient temperature gradients for spatial awareness. Hearing in Elaphe is rudimentary and tuned to low-frequency ground-borne vibrations rather than airborne sounds, transmitted through the lower jawbones to the inner ear via the quadrate and stapes. In the western ratsnake (Pantherophis obsoletus, formerly Elaphe obsoleta), auditory nerve fibers from the basilar papilla project to cochlear nuclei, with peak sensitivity at 50–100 Hz and thresholds around -29 dB re. ms⁻², allowing detection of approaching threats or prey movements through substrate conduction. This vibration-based system complements other senses but lacks the acuity for high-frequency aerial noises.Behavior and ecology
Locomotion
Elaphe snakes primarily utilize two gaits for terrestrial locomotion: lateral undulation and rectilinear progression. In lateral undulation, the most common mode on flat, open substrates, snakes generate a series of lateral bends that propagate posteriorly from the head, with each bend anchored by ventral scales against the ground for propulsion.[26] This gait allows efficient forward movement at steady speeds, with muscle activity synchronized to the bending wave.[26] Rectilinear locomotion, by contrast, involves direct, non-wavy advancement using ventral scale edges lifted and placed sequentially, powered by costocutaneous muscles, and is favored in narrow or cluttered environments where lateral bending is impractical.[27] Several Elaphe species exhibit strong climbing abilities, particularly in semi-arboreal taxa, employing modified lateral undulation or concertina motion to ascend trees and structures. Ventral scales with keeled edges provide grip on rough bark, enabling snakes to scale vertical surfaces up to several meters high.[28] In certain species, such as those in the Elaphe taeniura complex, the tail is semi-prehensile, allowing it to coil around branches for stability during navigation through arboreal canopies.[29] When traversing aquatic margins or streams, Elaphe snakes swim via undulating propulsion, similar to terrestrial lateral undulation but with amplified posterior wave amplitude to generate thrust against water resistance.[30] This mode relies on lateral body flexion without limb involvement, allowing effective movement in shallow waters. On land, Elaphe snakes are capable of rapid bursts during short pursuits or escapes, though sustained speeds are slower. These capabilities are supported by the elongated body morphology detailed in the physical description section.Foraging and predation
Species of the genus Elaphe are opportunistic generalists, with diets dominated by small mammals, particularly rodents such as mice and voles, which comprise the majority of their prey and contribute to their common name as rat snakes.[31][32] Other components include birds and their eggs (especially nestlings and passerine species), lizards, and occasionally frogs or bats, with prey selection influenced by availability and habitat.[31][32] Prey size correlates positively with snake body mass, allowing larger individuals like Elaphe quatuorlineata to target bigger rodents or birds, while juveniles focus on smaller items such as lizards.[31][33] Elaphe species employ a mix of ambush and active foraging strategies, relying heavily on chemosensory cues via tongue-flicking to detect and track prey odors over distances.[34][35] Upon locating prey, they strike rapidly and use powerful constriction coils to subdue it by restricting breathing and circulation, regardless of whether the victim is endothermic or ectothermic.[32] The snake then swallows the immobilized prey whole, with head-first orientation facilitating ingestion of items up to 50% of the snake's body mass in some cases.[33] For arboreal prey like bird nests, visual stimuli such as parental provisioning can guide snakes to elevated sites, enhancing detection in structurally complex environments.[34] As mid-level predators, Elaphe snakes play a key ecological role in controlling rodent populations, particularly in agricultural and forested habitats where they reduce pest densities and support biodiversity. This predation pressure helps mitigate crop damage from rodents and maintains balance in food webs across their Palearctic range.[31]Defensive strategies
Elaphe snakes employ a range of anti-predator behaviors to deter threats, primarily relying on bluffing displays to appear more formidable. When confronted, many species flatten their necks and heads to mimic the triangular shape of venomous vipers, a form of Batesian mimicry that exploits predators' aversion to dangerous species. For instance, juvenile four-lined snakes (Elaphe quatuorlineata) raise their forebody and flatten the head into a triangular form while hissing or striking, closely resembling sympatric nose-horned vipers (Vipera ammodytes meridionalis).[36] Additionally, these snakes often vibrate their tails rapidly against dry leaves or substrate, producing a rattling sound that imitates the warning signal of rattlesnakes, potentially confusing or alarming predators in shared habitats.[37] A key chemical defense in Elaphe involves musking, where individuals release foul-smelling secretions from cloacal glands to repel attackers. This odor, often described as pungent and feces-like, is deployed during direct threats and can persist on predators' mouths or bodies, discouraging further pursuit.[38] As a last resort, Elaphe snakes resort to physical aggression, including biting and constriction if captured. Bites are non-venomous but can cause pain and infection risk, serving as a deterrent rather than a primary offense. In some species, such as steppe rat snakes (Elaphe dione) and Amur rat snakes (Elaphe schrenckii), individuals may exhibit thanatosis or feigning death through extreme immobility and body-bending postures, resembling inanimate objects to convince predators the prey is already deceased.[39] Camouflage through cryptic coloration further aids initial avoidance, allowing these snakes to blend into their surroundings before active defenses are needed.[40]Life history
Hibernation and activity cycles
Species in the genus Elaphe inhabiting temperate regions of Eurasia undergo brumation, a period of dormancy analogous to hibernation in endotherms, to survive cold winters when environmental temperatures fall below critical thresholds, typically around 10°C. This physiological response involves reduced metabolic rates, slowed heart and respiratory functions, and minimal activity to conserve energy reserves accumulated during the active season. Brumation generally lasts 4-7 months, from late autumn to early spring, depending on latitude and local climate; for instance, Elaphe dione enters dormancy in mid-October and emerges in late March or early April in steppe habitats of Eastern Europe and Asia.[41][2] During brumation, individuals often aggregate in communal dens such as rock crevices, burrows, or rodent tunnels to maintain microclimates above freezing and minimize energy loss, with occasional brief emergences on mild days to bask and adjust body temperature near 5°C. Emergence is triggered by rising spring temperatures and lengthening daylight, prompting dispersal from dens and resumption of foraging and other behaviors. Post-hibernation, snakes exhibit heightened locomotor activity to exploit abundant resources. In species like Elaphe quatuorlineata, syntopic hibernation with other snakes in shared sites facilitates this communal strategy, though individual movement patterns vary with thermal cues during the transition periods.[38] Outside of brumation, Elaphe species display primarily diurnal activity patterns, emerging in the morning to bask on rocks, logs, or vegetation to achieve preferred body temperatures for optimal physiological function, such as digestion and locomotion. Thermoregulation via basking is crucial in ectothermic snakes, allowing them to select sun-exposed sites that raise body temperatures 5-10°C above ambient levels during the day. In hotter climates within their range, some populations shift to crepuscular activity to avoid midday heat stress while still relying on solar radiation for warming at dawn and dusk.[2] Variations in cycles occur across the genus, with tropical and subtropical species exhibiting reduced or absent brumation due to milder winters. For example, Elaphe taeniura in Southeast Asia shows minimal dormancy, maintaining year-round activity modulated by wet-dry seasons rather than temperature extremes, though brief periods of lowered metabolism may occur in cooler montane areas. These adaptations reflect the genus's broad distribution from temperate Europe to tropical Asia, where environmental cues like photoperiod and precipitation also influence seasonal rhythms.[42]Reproduction
Species of the genus Elaphe are predominantly oviparous, with females laying clutches of 5–30 eggs depending on species, female body size, and environmental conditions.[43][44] Clutch sizes average around 10–15 eggs in many species, such as Elaphe schrenckii (10–21 eggs) and Elaphe quatuorlineata (8–12 eggs), reflecting adaptations to resource availability and maternal investment.[44][45] Eggs are typically deposited in concealed sites like rotting logs or soil burrows during late spring or summer, following emergence from hibernation.[46] Mating occurs in spring shortly after hibernation ends, with males engaging in ritual combat to establish dominance and access to females. These combats involve wrestling-like behaviors where males intertwine their bodies, push against each other, and attempt to pin rivals, often lasting several minutes without serious injury. Multiple paternity is common within clutches, as females may mate with several males during the breeding season, enhancing genetic diversity; for instance, in Elaphe schrenckii, clutches can include offspring from up to three or more sires.[47] Eggs are incubated externally for 50–80 days at temperatures of 25–30°C, with optimal development around 27°C leading to higher hatching success.[46][48] Upon hatching, neonates measure 15–25 cm in length and receive no parental care, emerging fully independent and capable of foraging immediately.[49] In rare cases, high-altitude species such as Elaphe zoigeensis exhibit ovoviviparity, giving live birth to neonates adapted to cooler, shorter breeding seasons at elevations above 3,000 m.[5]Growth and lifespan
Juveniles of Elaphe species experience rapid post-hatching growth during their first year, often attaining approximately 50% of their adult body length by the end of this period, as observed in E. climacophora where individuals reach about 75 cm from a hatchling size of 40 cm within 15 months.[50] Growth rates are highest in the initial seasons, with no length increase occurring during hibernation periods from October to April, and individuals like E. quadrivirgata reaching 70–80 cm by the end of their second growing season.[51] This early acceleration supports quick development toward independence, though overall growth slows after sexual maturity, typically attained between 2 and 4 years of age depending on species and environmental conditions.[50] Sexual maturity in Elaphe is generally reached at a body length of 95–140 cm, corresponding to an estimated body mass threshold of 500–800 g in many species, beyond which reproductive capabilities emerge.[52] For instance, in E. quadrivirgata, females begin laying eggs at around 95–119 cm and males produce active sperm at 77 cm, often by 1.5–2 years under favorable conditions.[51] This size-based threshold ensures sufficient energy reserves for reproduction, varying slightly by sex and population. In the wild, Elaphe individuals typically live 10–20 years, with maximum recorded ages around 15–17 years, though predation and environmental stressors often limit survival. In captivity, lifespans extend to 20–30 years or more under optimal care, as seen in E. quadrivirgata reaching 16.8 years.[53] Predation remains a key factor reducing wild longevity, particularly for subadults. Juvenile mortality rates in Elaphe are high due to predation, dispersal risks, and environmental hazards, as evidenced by low recapture rates (e.g., only 7% of 274 released E. quadrivirgata juveniles survived to later sampling).[51] This elevated early-life mortality underscores the genus's reliance on high reproductive output for population persistence.[54]Distribution and habitat
Geographic range
The genus Elaphe is predominantly distributed across the Palearctic realm, spanning southern Europe, the Middle East, and much of Asia, with extensions into the Oriental region. Species occur from the Mediterranean Basin in the west to the Russian Far East and Japan in the east, and southward to parts of Southeast Asia and the Malay Archipelago. This wide-ranging distribution reflects the adaptability of these colubrid snakes to diverse temperate and subtropical environments, though no species are native to the Nearctic following taxonomic reclassifications that moved North American rat snakes to genera such as Pantherophis.[55][2] In Europe, Elaphe species are confined to the southern and southeastern regions, including the Balkans and Mediterranean countries. For instance, the four-lined snake (Elaphe quatuorlineata) inhabits areas from Italy and Greece through the Balkans to Albania and Croatia, often in fragmented populations. Further east, the steppe rat snake (Elaphe sauromates) ranges across southeastern Europe into the Caucasus and Central Asia, including Bulgaria, Romania, Ukraine, Kazakhstan, and Turkey. These European distributions are limited by climatic barriers, with no records north of the 50th parallel.[56][57][55] The core of the genus's diversity lies in Asia, where species occupy vast continental expanses from the Middle East to East Asia. In the Middle East and Caucasus, taxa such as Elaphe druzei (described in 2023), restricted to montane areas in Israel, Lebanon, and Syria, while Elaphe urartica extends across Armenia, Azerbaijan, Georgia, Iran, Iraq, and eastern Turkey. Central and East Asian species include the widely distributed Amur rat snake (Elaphe schrenckii), found in northeastern China, Russia, Mongolia, and the Korean Peninsula, and the Japanese rat snake (Elaphe climacophora), native to Japan and the southern Kuril Islands. In southern Asia, Elaphe dione spans from Afghanistan and Iran through Mongolia and northern China to Russia. Oriental extensions feature species like Elaphe taeniura, which ranges from India and Bhutan through Myanmar, Vietnam, and Indonesia to the Philippines and Malay Archipelago. Recent discoveries, such as Elaphe zoigeensis in Sichuan Province, China (described in 2012), Elaphe ganziensis in western Sichuan Province, China (described in 2021), and Elaphe xiphodonta in Shaanxi Province (described in 2021), highlight ongoing taxonomic refinements in this region.[18][58][59][5] Introduced populations of Elaphe species exist outside their native ranges, primarily due to historical releases or escapes. Elaphe quadrivirgata has established feral populations in New Zealand, and Elaphe taeniura has been introduced to both New Zealand and South Africa, where they pose potential ecological risks as invasive predators. No native or introduced populations persist in the Americas under the current Elaphe classification, as former Nearctic species like the black rat snake (previously Elaphe obsoleta) were reclassified to Pantherophis obsoletus in 2009, with no subsequent reversals as of 2025.[55][60][61]| Region | Representative Species | Key Countries/areas |
|---|---|---|
| Southern Europe | E. quatuorlineata, E. sauromates | Italy, Greece, Bulgaria, Romania |
| Middle East/Caucasus | E. druzei, E. urartica | Israel, Syria, Turkey, Iran |
| East Asia | E. schrenckii, E. climacophora, E. davidi | China, Japan, Russia, Korea |
| Central/South Asia | E. dione, E. cantoris, E. hodgsonii | Mongolia, India, Nepal, Afghanistan |
| Southeast Asia/Oriental | E. carinata, E. taeniura, E. moellendorffi | Vietnam, Indonesia, Taiwan, Myanmar |
| Introduced | E. quadrivirgata, E. taeniura | New Zealand, South Africa |