Fact-checked by Grok 2 weeks ago

Sharp-tailed snake

The sharp-tailed snake (Contia tenuis), also known as the common sharp-tailed snake, is a small, nonvenomous species in the family Colubridae, characterized by its slender body, smooth unkeeled scales, and a distinctive thorn-like scale at the tail tip that facilitates prey extraction.^[1] Adults typically reach 8 to 12 inches (20 to 30 cm) in total length, though rarely up to 19 inches (48 cm), with a uniform grayish-brown to reddish-brown coloration often featuring a faint mid-dorsal stripe.^[2]^[3] Native to the Pacific Coast region, it inhabits moist microhabitats such as forest edges, oak woodlands, meadows, and rocky areas with abundant surface cover like logs and leaf litter, preferring damp conditions near streams or in south-facing canopy gaps.^[4]^[3] This secretive, semi-fossorial snake is primarily nocturnal or crepuscular, foraging under debris for its main prey of slugs, snail eggs, and occasionally small salamanders, using its specialized tail to spear and pull soft-bodied invertebrates from shells.^[5]^[2] Oviparous reproduction occurs with mating in spring, followed by the laying of 3 to 8 eggs in late June or July, which hatch in fall; little is known about exact nesting sites or maturity age due to the species' elusive nature.^[3]^[4] Its distribution spans patchily from central California northward through Oregon and Washington to southeastern Vancouver Island and the Gulf Islands in British Columbia, with populations considered relict at the northern extent.^[6]^[7] Globally assessed as Least Concern by the IUCN due to its relatively wide range, the sharp-tailed snake faces localized threats from habitat fragmentation, urbanization, and invasive species in northern populations, where Canadian subpopulations are designated as Threatened or Endangered under national conservation frameworks.^[3]^[7] Its conservation status highlights vulnerabilities in specific biogeoclimatic zones like Coastal Douglas-fir, underscoring the need for targeted habitat protection despite overall stability.^[1]^[8]

Taxonomy and Nomenclature

Classification and Phylogeny

The sharp-tailed snake (Contia tenuis) belongs to the class Reptilia, order Squamata, suborder Serpentes, family Colubridae, subfamily Dipsadinae, and genus Contia.^[9] This classification reflects its position among advanced snakes (Caenophidia), characterized by features such as a single row of teeth on the palatine bone and rear maxillary teeth adapted for prey constriction rather than venom delivery.^[10] Phylogenetically, Contia tenuis represents one of two extant species in the genus Contia, alongside the forest sharp-tailed snake (C. longicaudae), which was elevated from synonymy with C. tenuis in 2010 based on mitochondrial DNA sequence divergence (up to 5.3% in cytochrome b) and morphological traits like relative tail length and scale counts.^[11] The genus Contia forms a distinct, relict lineage within Colubridae, exhibiting deep genetic divergence from other North American colubrids and no close affinities to neighboring genera such as Diadophis or Heterodon, as evidenced by analyses of 12S and 16S ribosomal RNA genes.^[10] This isolation suggests an ancient divergence, potentially tracing to early Caenophidian radiations in the Miocene, with Contia retaining primitive traits amid the family's diversification into over 2,000 species.^[7] Mitochondrial studies across the range of C. tenuis reveal low intraspecific variation (e.g., 0.5–1.2% pairwise differences in ND4 and cytochrome b genes), supporting monophyly for the species but indicating cryptic population structuring tied to coastal versus inland lineages, possibly due to Pleistocene vicariance rather than ongoing gene flow.^[12] Broader squamate phylogenies confirm Colubridae's paraphyly in some analyses, but Contia consistently nests within Dipsadinae, underscoring its evolutionary conservatism as a small, slug-specialized form amid colubrid expansion.^[13]

Etymology and Synonyms

The genus name Contia honors John Lawrence LeConte (1825–1883), an American entomologist and naturalist.^[14]^[2] The specific epithet tenuis derives from Latin, meaning "slender," "thin," or "narrow," in reference to the species' elongate, slim body form.^[14]^[2] The binomial Contia tenuis was originally described by Spencer Fullerton Baird and Charles Frédéric Girard in 1852.^[14] Junior synonyms include Calamaria tenuis Baird & Girard, 1852, and Contia mitis Baird & Girard, 1853.^[15] Until a taxonomic revision in 2009–2010, populations now assigned to Contia longicauda (forest sharp-tailed snake) were subsumed under C. tenuis, but molecular and morphological analyses supported their separation as a distinct species endemic to higher-elevation coniferous forests.^[11]^[16]

Common Names

The sharp-tailed snake (Contia tenuis) is primarily known by its English common name "sharp-tailed snake," derived from the distinctive elongated, spine-like scale at the tip of its tail, which aids in burrowing and navigation through leaf litter.^[17] This name is widely used in scientific literature and conservation assessments across its range in western North America.^[8] Variants include "common sharp-tailed snake," emphasizing its relatively widespread but secretive occurrence in suitable habitats, and "sharptail snake," a shortened form appearing in herpetological databases and field guides.^[18] ^[19] The French common name "couleuvre à queue fine" translates to "slender-tailed snake," highlighting the species' thin, tapered tail morphology rather than the sharpness.^[8] Historical synonyms in older North American herpetology include "gentle brown snake" (Contia mitis), reflecting early observations of its docile behavior and brownish dorsal coloration, as well as "Oregon worm snake" (Lodia tenuis), underscoring its slender, fossorial form resembling a worm.^[20] These alternative names are now largely obsolete in favor of the tail-focused descriptors, which better align with diagnostic morphological traits confirmed through specimen examinations.

Physical Description

Morphology and Size

The sharp-tailed snake (Contia tenuis) is a small, slender colubrid characterized by a cylindrical body, a head that is slightly wider than the neck but not distinctly demarcated, and a short tail terminating in a sharp, thorn-like scale.^[7] Adults typically measure 20 to 30 cm in total length, with a maximum recorded up to approximately 48 cm, though such extremes are rare.^[2] ^[3] Hatchlings emerge at 7.6 to 10 cm in length.^[2] ^[21] Dorsal scales are smooth and unkeeled, arranged in 15 rows at midbody, contributing to the snake's sleek, worm-like appearance.^[3] The body is roughly pencil-thick in diameter, adapted for fossorial habits in leaf litter and soil.^[22] The tail comprises a small proportion of total length, averaging less than 20% and featuring 42 to 43 subcaudal scales divided by a single anal plate.^[2] Sexual maturity is reached at snout-vent lengths of around 21 to 25 cm, with gravid females averaging 26 cm snout-vent length.^[23]

Coloration and Scalation

The sharp-tailed snake (Contia tenuis) displays a dorsal coloration typically ranging from reddish-brown to grayish-brown, with juveniles exhibiting brighter tones than adults.^[2]^[3] Indistinct reddish dorsolateral stripes may extend along the anterior third of the body, while the head is medium to light olive-gray or brown, often marked with black flecking or blotches and occasionally orange spots.^[2] Red pigmentation intensifies toward the tail, and some individuals feature a narrow copper-red or yellow collar encircling the neck.^[5]^[24] Ventrally, the snake has a pale cream, gray, or pale greenish background with alternating black bars, formed by dark markings across the anterior edge of each ventral scute, creating a checkered appearance that fades posteriorly and is absent on the anal plate and subcaudals.^[2]^[4] These black crossbars are notably wide, covering one-half to one-third of each anterior ventral scale.^[25] Scalation consists of smooth, unkeeled dorsal scales arranged in 15 rows at midbody.^[3] Ventral scutes number approximately 120–150, while subcaudals total 40–60, typically divided, with a distinctive thorn-like scale projecting from the tail tip that gives the species its common name.^[1]^[2] The anal plate is divided.^[1]

Sexual Dimorphism

Sexual dimorphism in the sharp-tailed snake (Contia tenuis) is modest, manifesting primarily in body size and relative tail length. Adult females attain larger snout-vent lengths (SVL) than males, with mean values of 251 ± 28 mm for females compared to 212 ± 14 mm for males in a studied population from British Columbia.^[26] This female-biased size dimorphism aligns with patterns in many colubrid snakes, where larger female body size supports greater reproductive output, such as clutch sizes averaging 3.6 eggs.^[27] Females also tend to mature later and at larger SVL than males, though data remain limited.^[1] Males exhibit proportionately longer tails relative to total body length, a common trait in snakes to accommodate hemipenes and associated musculature for mating. Relative tail lengths in males range from approximately 17.3% to 22.4% of total length, overlapping with but generally exceeding those in females (15.4% to 19.8%). Adult females, however, show higher incidences of tail tip scarring and shortening, potentially linked to defensive autotomy or habitat-related wear.^[28] No significant dimorphism has been noted in scalation or coloration patterns.^[28]

Distribution and Habitat

Geographic Range

The sharp-tailed snake (Contia tenuis) inhabits western North America, with its range extending from southwestern British Columbia, Canada, southward through Washington and Oregon to central California in the United States.^[1] In Canada, the species is restricted to southeastern Vancouver Island and the adjacent southern Gulf Islands, representing the northern limit of its distribution.^[23] Within the United States, populations occur discontinuously across moist coastal and foothill regions, with records from low-elevation coniferous forests and oak woodlands.^[2]^[4] In California, the snake is found from the northern coast near Eureka southward along the coastal ranges to central San Luis Obispo County, as well as along the western slopes of the Sierra Nevada foothills.^[3] Inland extensions reach into parts of Oregon, where recent surveys indicate a broader distribution than previously thought, including expanded records in the state's western counties.^[6] The overall range reflects a preference for mesic habitats within a Mediterranean to temperate climate zone, though the species exhibits patchy occurrence due to specific microhabitat requirements.^[8] Note that taxonomic revisions proposed in 2010 suggest splitting C. tenuis into two species, with the northern form (C. nuchalis) limited to British Columbia, but this change is not universally adopted in current distributions.^[8]

Habitat Preferences

The sharp-tailed snake (Contia tenuis) primarily inhabits low- to mid-elevation environments characterized by open-canopy woodlands and transitional zones between forests and grasslands, often favoring sites with access to surface moisture despite occurring in relatively arid regions. Preferred habitats include Douglas-fir-dominated woodlands, particularly coastal variants with Garry oak (Quercus garryana) and arbutus (Arbutus menziesii), as well as mixed oak-conifer stands and riparian areas adjacent to intermittent streams.^[23]^[3] These snakes are frequently associated with shrubsteppe, chaparral, and grassland edges, where shallow soils support leaf litter and rocky outcrops, extending from sea level up to approximately 2,130 m (7,000 ft) in elevation, though most populations occupy sites below 400 m in their northern range.^[4]^[2] Microhabitat selection emphasizes cover for thermoregulation, foraging, and refuge, with individuals commonly found under rocks, logs, coarse woody debris, bark, or artificial objects like asphalt shingles on south-facing slopes that provide solar exposure and moisture retention.^[23]^[3] Activity peaks in damp conditions, such as post-rainfall or during cool fall and winter periods, underscoring a dependence on localized humidity within drier matrices; talus slopes, gravel piles, and leaf litter accumulations serve as critical refugia, while the species tolerates human-modified landscapes like yards and gardens if sufficient cover persists.^[2]^[3] Habitat fragmentation from development poses risks, as C. tenuis exhibits limited dispersal and fidelity to specific cover features.^[23]

Microhabitat Use

The sharp-tailed snake (Contia tenuis) is semi-fossorial and primarily utilizes microhabitats providing cover, moisture retention, and thermal moderation, such as crevices in soil or bedrock, spaces under surface objects, and burrows in loose substrates.^[7] These snakes frequently shelter under rocks, coarse woody debris including decaying logs and stumps, bark, and leaf litter, particularly in areas with shallow soils, high rock cover, and southern exposures that facilitate thermoregulation.^[7]^[3] Observations indicate a strong association with talus slopes and rocky outcrops near open-canopy woodlands, where they exploit moist conditions for hiding and foraging, often emerging under artificial or natural cover objects during the rainy season from October to April.^[29]^[3] For hibernation, adults seek underground refugia in southwest-facing forest openings, talus patches, or crevices, with records from sites like Observatory Hill and artificial talus slopes in the Pemberton Valley where snakes were detected in spring from 2013 to 2016.^[7] Egg-laying occurs in communal nests buried 7–15 cm deep in soil among grass roots or near rock outcrops, favoring rocky slopes with southern exposure to provide warmer microclimates for incubation and hatching, which typically happens in fall.^[3] Hatchlings have been observed near talus on south- or southwest-facing slopes adjacent to hibernation sites.^[7] Foraging microhabitats overlap with shelter sites, centered on moist areas with surface debris like twigs and roots where primary prey such as slugs are abundant, reflecting the snake's preference for cooler, humid conditions distinct from more arid habitats used by sympatric species.^[3]^[7]

Behavior and Ecology

Activity Patterns and Thermoregulation

The sharp-tailed snake (Contia tenuis) displays highly seasonal surface activity, with peaks in spring from March to early June and in fall from September to November, reflecting adaptation to cooler temperatures and moist conditions that limit exposure to extremes.^[7]^[30] In coastal regions, individuals may remain active year-round under favorable microclimates, though inland populations exhibit reduced summer activity due to heat and drought, and overwinter in hibernation from late fall to early spring.^[7] Daily patterns are secretive and semi-fossorial, with most activity occurring under cover objects like rocks or logs during cooler periods of the day; nocturnal foraging has been observed on warm summer nights following rain, particularly where prey slugs are abundant.^[7]^[30] Movements are limited, typically within small home ranges averaging 180 m², underscoring a sedentary lifestyle that minimizes energy expenditure and predation risk.^[7] As an ectothermic reptile, the sharp-tailed snake relies on behavioral thermoregulation, selecting south- and west-facing rocky slopes, talus fields, and canopy gaps to access warmer microhabitats for optimal body temperatures.^[31]^[30] Field observations record active snakes at substrate temperatures of 11–16°C, with laboratory preferences for 20–22°C, while cover objects can reach 7–46°C, allowing shuttling between shelters to maintain homeostasis amid diurnal and seasonal fluctuations.^[7] This strategy is evident in habitat affinity for open woodlands with coarse woody debris and talus, which buffer against overheating in summer and provide refugia during colder periods, though populations show sensitivity to warmer regional trends that may disrupt these niches.^[7]^[31]

Locomotion and Defensive Mechanisms

The sharp-tailed snake (Contia tenuis) is semi-fossorial and secretive in its movements, primarily active diurnally during the rainy season from October through April, when it forages under surface cover such as leaf litter and rocks.^[3] Individuals typically exhibit limited dispersal, with radio-telemetry studies recording maximum straight-line movements of 93 m over three weeks in adults and up to 139 m over multiple years in tracked specimens.^[1]^[7] Its slender body facilitates rapid evasion into crevices, relying on standard serpentine undulation for surface travel and likely concertina locomotion in confined spaces, aided by the sharp, keeled tail tip for anchoring during prey capture or navigation.^[32] Defensive behaviors emphasize crypsis and evasion over confrontation, with the snake's brownish coloration and small size (typically 20-30 cm) allowing it to blend seamlessly into leaf litter or soil, avoiding detection by predators.^[33] When handled or threatened, C. tenuis thrashes side-to-side and jabs the pointed tail spine into the captor, causing surprise but little harm, while often coiling into a tight ball to shield the head within body loops.^[29]^[34] Observations also document immobilization and tumbling onto the back to feign death, particularly in juveniles, as an antipredator tactic.^[35] These mechanisms, combined with its preference for hiding under rocks or logs, contribute to low encounter rates despite relatively secure population statuses in core ranges.^[2]

Interactions with Predators

The sharp-tailed snake (Contia tenuis) is preyed upon by a variety of vertebrates, including diurnal birds, small mammals, and larger snakes, though documented instances of predation remain scarce.^[1] In regions such as Vancouver Island and the Gulf Islands, the invasive common wall lizard (Podarcis muralis) has rapidly expanded since the early 2000s, emerging as a novel predator that forages under cover objects where C. tenuis seeks refuge, potentially increasing mortality rates among juveniles and adults.^[7] To counter predation, C. tenuis employs several antipredator tactics, notably coiling into a tight ball with the head tucked inward to present a compact, armored profile that resists manipulation or swallowing by predators.^[35] Juveniles exhibit this balling behavior prominently during threats, alongside vigorous thrashing when handled, which may dislodge attackers or create escape opportunities; adults show an ontogenetic shift toward less frequent balling but retain similar responses.^[36] Additional defenses include pricking assailants with the pointed, keratinized tail spine—a modified scale—and expulsion of offensive cloacal secretions to deter close-range encounters.^[35] These behaviors, combined with the snake's secretive microhabitat preferences under rocks and logs, minimize exposure but offer limited protection against persistent or novel predators like invasive lizards.^[22]

Diet and Foraging

Primary Prey Species

The sharp-tailed snake (Contia tenuis) primarily preys on slugs, which constitute the majority of its diet across its range in western North America.^[3]^[24] This specialization is supported by observations of the snake's elongated posterior teeth, adapted for grasping slippery, soft-bodied prey like slugs.^[17] Slugs from genera such as Arion (e.g., invasive garden slugs) and native species like the banana slug (Ariolimax columbianus) in coastal habitats are commonly consumed, though specific prey taxa are not exhaustively documented due to the snake's secretive nature and limited field studies.^[22]^[2] Secondary prey items, observed less frequently, include slug eggs, terrestrial snails, and small amphibians such as slender salamanders (Batrachoseps spp.), but these do not dominate the diet.^[24]^[2]^[5] The reliance on slugs aligns with the snake's foraging in moist microhabitats, where prey abundance correlates with humidity and leaf litter cover, potentially making populations vulnerable to drought-induced prey scarcity.^[23] No records confirm predation on vertebrates beyond occasional salamanders or on harder-bodied invertebrates like insects as staples.^[3]

Hunting and Feeding Strategies

Sharp-tailed snakes are active foragers that primarily hunt in moist, covered microhabitats such as under decaying logs, rocks, and leaf litter, where slugs are abundant.^[37] They exhibit nocturnal activity patterns, foraging during cooler hours like dawn, dusk, or night to coincide with prey availability in damp environments.^[33] This secretive, semi-fossorial lifestyle minimizes exposure while facilitating searches within small home ranges, typically averaging 25 meters in diameter.^[37] Prey detection relies heavily on chemoreception, with the snakes using frequent tongue flicks to sample chemical cues from the substrate and air. In controlled experiments with 13 adults, tongue flick rates increased significantly in response to slug odors (mean 39.7 flicks/min) compared to earthworm odors (13.8 flicks/min; P < 0.0001), indicating a behavioral preference for slugs.^[38] Latency to first tongue flick was similar for both (slug: 4.1 ± 1.57 s; earthworm: 6.0 ± 1.87 s), suggesting efficient discrimination via olfactory processing in the vomeronasal system.^[38] Upon locating a slug, the snake employs its specialized dentition—long, narrow, recurved posterior teeth on the mandibles—to grasp the slippery, soft-bodied prey.^[39] These needle-like teeth, an adaptation for handling mucus-covered invertebrates, allow secure hold without constriction or venom, enabling the snake to maneuver and swallow the prey whole.^[1] Diet consists almost exclusively of small slugs, including invasive species like those in the genus Arion, consumed year-round but peaking in moist seasons from February to April and September to November.^[37]^[40]

Reproduction and Life History

Mating Behavior

Mating in Contia tenuis is believed to occur primarily in spring, coinciding with the snakes' emergence from winter dormancy.^[29]^[3] Encounters of male-female pairs during this period have been noted in regions such as British Columbia, suggesting active courtship or copulation.^[29] However, detailed observations of courtship rituals, such as tactile stimulation or pheromonal cues typical in colubrid snakes, remain undocumented due to the species' secretive, fossorial habits that limit field studies.^[30] The secretive nature of C. tenuis has resulted in scant empirical data on mating specifics, with much of the available information inferred from captive observations or incidental field sightings rather than systematic research.^[30]^[5] Females typically reach sexual maturity at 2–3 years and produce clutches annually, but the precise mechanisms of mate selection or sperm storage—potentially involving delayed fertilization as seen in related taxa—have not been verified.^[1] Isolated reports of paired snakes in non-spring contexts exist but lack corroboration from peer-reviewed sources and may reflect anomalous behavior rather than normative patterns.^[30]

Egg Laying and Incubation

The sharp-tailed snake (Contia tenuis) is oviparous, with females typically laying eggs in late June or July following breeding in April or May.^[4]^[2] Clutch sizes range from 3 to 5 eggs, though limited observations suggest variability up to 8 in some populations.^[23] Eggs are often deposited in communal nest sites, such as under rocks, logs, or in south-facing talus slopes that provide suitable microhabitats for oviposition.^[3]^[37] Incubation occurs externally without parental attendance, relying on environmental conditions in the nesting substrate. Hatching takes place in late summer to fall, with embryos developing over approximately 2–3 months influenced by soil temperature and moisture.^[1]^[41] In coastal British Columbia populations, where this is the only native oviparous snake, incubation temperatures affect developmental rates and potentially sex ratios, though specific thresholds for C. tenuis remain undocumented in peer-reviewed studies.^[7] Hatchlings emerge at lengths of about 10 cm, dispersing independently shortly after.^[42]

Growth and Lifespan

Young sharp-tailed snakes (Contia tenuis) hatch in the fall from clutches of 3–5 eggs laid by females in late June or July.^[23]^[1] Hatchlings and juveniles exhibit relatively rapid initial growth, with estimated rates reaching approximately 30 mm per year in snout-vent length (SVL) for individuals under 120 mm SVL, though precise measurements for very small juveniles are challenging due to mark-recapture limitations.^[26] This growth trajectory allows most individuals to attain adult SVL of about 200 mm—typical for mature snakes—within roughly three years.^[30]^[37] Larger adults may extend to 300–475 mm total length, but growth slows in older individuals to 7–14 mm per year.^[3] Sexual maturity is typically achieved in 2–3 years, consistent with patterns in comparably sized colubrid snakes, though exact age at first reproduction remains undocumented for C. tenuis.^[23] In the wild, sharp-tailed snakes have a documented lifespan of at least 6–7 years, with potential for longer based on recapture data from marked populations; annual survival rates of 0.53–0.73 support finite population models projecting similar longevity.^[22]^[7] Captive longevity records are unavailable in surveyed herpetological literature, limiting comparisons to wild estimates. Whether iteroparity (annual reproduction) occurs post-maturity is unknown, potentially influencing effective lifespan in reproductive terms.^[22]

Conservation and Population Dynamics

Current Status and Threats

The sharp-tailed snake (Contia tenuis) is assessed as Least Concern on the IUCN Red List, reflecting its broad distribution from southern British Columbia through California to northern Baja California, with stable populations in much of its core range.^[3] However, regional assessments highlight vulnerabilities: in Canada, it is designated Endangered by COSEWIC, with the Pacific Coast population estimated at approximately 12,000 mature individuals and the Coast Mountains population at around 350, confined to fragmented habitats in southwestern British Columbia.^[23] In Washington state, it is considered of conservation concern due to limited documented populations and patchy occurrence, lacking comprehensive data on trends.^[4] NatureServe ranks the global status as Secure (G5), but designates the Pacific Coast subpopulation as Threatened and the Coast Mountains as Endangered, emphasizing risks from isolation and small sizes.^[8] Primary threats include habitat loss and fragmentation from urban development, deforestation, and forestry practices, which degrade talus slopes, leaf litter understory, and woodland edges essential for foraging and shelter.^[4]^[43] Road construction and traffic contribute to direct mortality via vehicle strikes, while off-trail recreation and introduced predators (such as domestic cats) exacerbate declines in peripheral populations. In British Columbia, ongoing sprawl in coastal areas poses the greatest risk, with stochastic events like fires or floods threatening small, isolated groups due to limited dispersal.^[44] Persecution by humans, though minor, persists in some locales where the snake is mistaken for venomous species.^[45] Climate change may indirectly intensify pressures by altering moisture regimes in arid habitats, but empirical data on this remains limited.^[1]

Population Trends and Discoveries

The sharp-tailed snake (Contia tenuis) exhibits stable or abundant populations in core parts of its range in California and Oregon, where it is not considered at risk, but peripheral northern populations in British Columbia and Washington show signs of decline or stagnation due to habitat fragmentation and limited monitoring data.^[6]^[5] In British Columbia, COSEWIC infers ongoing declines from habitat loss trends, with one long-term study estimating a population growth rate of 0.89 (95% CI: 0.79–1.1) over an 8-year period in a monitored site, indicating potential slight contraction.^[23]^[26] Detection of trends remains challenging without broader surveys, as only select sites like Magic Prairie have been tracked since 1997, revealing no clear upward trajectory.^[44] In Washington, the species' patchy distribution and small number of verified sites contribute to conservation concerns, though quantitative trend data is scarce.^[4] Globally, NatureServe ranks C. tenuis as secure (G5), reflecting resilience in southern habitats despite localized pressures.^[8] Recent discoveries have incrementally expanded documented occurrences, particularly in northern extents. In western Washington, prior to 2013 only five verified records existed west of the Cascade crest; between 2013 and 2017, nine additional observations were recorded, including the first confirmed sighting on San Juan Island's Cady Mountain.^[46] In British Columbia, three of the eight known populations were identified since 2003 through targeted searches, with a notable cluster of 15 records across 10 sites near Pemberton emerging after a 2011 discovery.^[1]^[41] These findings suggest under-sampling rather than range contraction in some areas, though they do not offset inferred habitat-driven declines.^[23]

Conservation Measures and Research

In Canada, the Sharp-tailed snake's Pacific Coast population is designated as Endangered under the federal Species at Risk Act, prompting the development of recovery strategies focused on habitat protection, stewardship agreements with landowners, and targeted inventories to identify occupied sites.^[23] These measures include restricting development in known habitats, promoting voluntary conservation easements, and conducting surveys under artificial cover objects to map distributions while minimizing disturbance.^[47] In British Columbia, provincial recovery efforts emphasize long-term monitoring protocols established in 2006, which guide standardized searches during optimal seasonal conditions to assess population viability.^[48] Research on the species has advanced detection methods for its cryptic, fossorial habits, including the validation of environmental DNA (eDNA) assays in 2021 that analyze swabs from cover objects and soil samples, improving survey efficiency in fragmented habitats.^[49] Studies have quantified threats such as habitat loss from urbanization and predation by introduced species, informing mitigation like road underpasses and cat control in core areas.^[17] Ongoing investigations into microhabitat preferences, such as talus slopes and leaf litter depth, support refined protection guidelines, though data gaps persist on dispersal rates and climate impacts.^[6] In Washington state, conservation actions prioritize inventory expansion due to the species' patchy distribution and limited records, with state wildlife agencies collaborating on non-invasive tracking to evaluate connectivity between subpopulations.^[4] Functional rarity assessments in British Columbia highlight the need for research into ecological roles, such as slug predation, to justify enhanced protections amid low densities.^[26] Globally, the species' Least Concern status by the IUCN underscores that measures are regionally driven, with U.S. populations generally stable but monitored for edge effects from agriculture and recreation.^[50]

References

[1]
[PDF] Sharp-tailed Snake (Contia tenuis) - Species at risk public registry
The snakes inhabit relatively open-canopy woodlands dominated by Douglas-fir,. Arbutus, and/or Garry Oak within the Coastal Douglas-fir Biogeoclimatic Zone.
[2]
Common Sharp-tailed Snake - Contia tenuis - California Herps
Common Sharp-tailed snakes are often found in suburban northern California yards and gardens while raking or turning over surface objects, especially on sunny ...
[3]
Contia tenuis (Sharptail Snake) - Animal Diversity Web
Habitat. Sharp-tailed Snakes occur in a variety of habitats, however, they are most commonly found in moist environments with an abundance of surface debris, ...
[4]
Common sharp-tailed snake (Contia tenuis)
They are often near streams or in other damp habitats. Small canopy gaps with rocky substrates, particularly those that are south-facing, may be important for ...
[5]
Common Sharp-tailed Snake (Contia tenuis)
Aug 1, 2013 · A sharp-tailed snake (Contia tenuis) in the San Juan Islands: Western Washington's first record in 58 years. Northwestern Naturalist 89:107-109.Missing: IUCN | Show results with:IUCN
[6]
[PDF] CURRENT DISTRIBUTION AND STATUS OF SHARP-TAILED ...
Hence, it has been assumed to be rare over much of its distribution. Its range is lim- ited to parts of California, Oregon, Washing- ton, and extreme ...
[7]
[PDF] Sharp-tailed Snake Contia tenuis - Wildlife, plants and species
The species exists at the northern limits of its range in southern British Columbia, and present-day populations are probably relicts from a more extensive past ...
[8]
Contia tenuis | NatureServe Explorer
Habitat Comments: Habitat includes moist situations in pastures, meadows, oak woodlands, broken chaparral, and the edges of coniferous or hardwood forests ( ...
[9]
Explore the Taxonomic Tree | FWS.gov - U.S. Fish and Wildlife Service
Location in Taxonomic Tree ; Suborder, Serpentes ; Infraorder, Alethinophidia ; Family, Colubridae ; Subfamily, Dipsadinae ; Genus, Contia.
[10]
Relict snakes of North America and their relationships within ...
This paper focuses on the phylogenetic relationships of eight North American caenophidian snake species (Carphophis amoena, Contia tenuis, Diadophis ...
[11]
[PDF] A New Species of Snake in the Genus Contia (Squamata
Jul 10, 2009 · However, genetic and morphological data readily distinguish C. longicaudae as distinct from C. tenuis. Contia longicaudae is genetically ...
[12]
Mitochondrial Variation in Sharp-Tailed Snakes (Contia tenuis ...
We examined genetic variation and structure in mitochondrial DNA sequences of sharp-tailed snakes (Contia tenuis) from California and southern Oregon.
[13]
A phylogeny and revised classification of Squamata, including 4161 ...
The estimated phylogeny contains 4161 species, representing all currently recognized families and subfamilies. The analysis is based on up to 12896 base pairs ...
[14]
Contia tenuis (BAIRD & GIRARD, 1852) - The Reptile Database
Etymology, Named after Latin “tenuis” = slender. The genus was named after John Lawrence LeConte (1825-1883), US American entomologist and naturalist.
[15]
http://reptile-database.reptarium.cz/species?genus=contia&species=tenuis
[16]
Sharp-tailed Snake in Bay Area : sfbaywildlife.info
In 2010, this species was split into two - Sharp-tailed Snake (Contia tenuis) and Forest Sharp-tailed Snake (Contia longicauda). The latter is found only on ...Missing: scientific synonyms
[17]
None
Summary of each segment:
[18]
Sharp-tailed Snake (Contia tenuis) | U.S. Fish & Wildlife Service
Scientific Name: Contia tenuis. Common Name: Sharp-tailed Snake. Sharptail Snake. Common Sharp-tailed Snake. Kingdom: Animalia.
[19]
contia tenuis | The Reptile Database
Subspecies ; Common Names, E: (Common) Sharptail Snake G: Dornschwanzschlange ; Synonym, Calamaria tenuis BAIRD & GIRARD 1852. Contia mitis BAIRD & GIRARD 1853: ...
[20]
Contia tenuis - The Center for North American Herpetology
A patronym honoring John Lawrence LeConte (1825–1883), a prominent American ...Missing: classification | Show results with:classification
[21]
[PDF] Sharp-tailed Snake Identification Guide - Gov.bc.ca
Sharp-tailed Snake (Contia tenuis). SIZE Small and slender, worm-like; length of adults about 20–30 cm; length of young at hatching about. 10 cm. COLOUR ...<|control11|><|separator|>
[22]
[PDF] Sharp-tailed Snake - Ministry of Environment and Parks
The Sharp-tailed Snake occurs in a relatively densely populated part of the province where natural habitats have undergone exten- sive modification since ...Missing: evolutionary | Show results with:evolutionary
[23]
Sharp-tailed Snake (Contia tenuis): COSEWIC assessment and ...
Nov 17, 2022 · Sharp-tailed Snake is one of only two species in the genus Contia, not closely related to any other genera. It provides material for study of ...
[24]
Sharp-tailed Snake - Burke Museum
Contia tenuis. What they look like. Sharp-tailed snakes are small snakes with an average length of 8 to 12 inches. They have smooth shiny scales that are gray ...Missing: size behavior
[25]
Identifying Sharp-tailed Snakes (Contia) - California Herps
The cross bands on C. tenuis are thicker, covering 1/2 to 1/3 of each ventral. There are also subtle differences in dorsal and ventral coloration and ...
[26]
[PDF] Case of the Sharp-tailed Snake (Contia tenuis)
Reproductive and nesting ecology of the Yellow-Blotched Map. Turtle, Graptemys flavimaculata: implications for conservation and management. Copeia 2003:729–738.
[27]
Spatial distribution and abundance of Common Sharp-tailed Snakes ...
They were slow growing (adult growth rate, 4.3 ± 3.8 mm/yr), had extended time-to-sexual maturity (5-6 yr), and had small clutch size (3.6 ± 1.1 eggs).
[28]
current distribution and status of sharp-tailed snakes (contia tenuis ...
Aug 5, 2025 · Contia tenuis is a semi-fossorial snake found in a ... sexual dimorphism, age classes, and reproduction of this state listed subspecies.
[29]
Common Sharp-tailed Snake - B.C. Reptiles & Amphibians
The Common Sharp-tailed Snake is the smallest snake species in British Columbia, reaching a maximum length of 20-45 cm and about the thickness of a pencil.
[30]
[PDF] Natural History of the Sharp-Tailed Snake, Contia tenuis, on the Gulf ...
The sharp-tailed snake, Contia tenuis, is considered endan- gered nationally ... The longest movement detected for the other tagged snake, an adult male, was 93 m ...<|control11|><|separator|>
[31]
[PDF] JNAH ISSN 2333-0694 - Journals@KU
INTRODUCTION. Common Sharp-tailed Snakes (Contia tenuis) are small, slender, semi-fossorial snakes patchily distributed throughout the entire northern half ...<|separator|>
[32]
Sharp-Tailed Snake - Contia tenuis - A-Z Animals
They are carnivores eating mostly a diet of slugs. Sharptail snakes are small in size and non-venomous which is why they are kept as a pet in some households. 5 ...
[33]
https://www.battlbox.com/blogs/outdoors/do-sharp-tailed-snakes-bite-understanding-their-behavior-and-nature
[34]
Snake Behavior and Life History - Defensive Strategies
When threatened, some snakes will also coil up into a ball with the head protected inside the coils of the body. Sharp-tailed Snake · california kingsnake.
[35]
[PDF] Observations of Antipredator Tactics of the Sharp-Tailed Snake ...
(A) After a few minutes of handling, this hatchling Contia tenuis coiled and immobilized the body; when returned to the ground it tumbled onto its back ...
[36]
Natural History Notes: Serpentes - ProQuest
We interpret the behavior of juvenile C. tenuis as a defense against predators and suggest that an ontogenetic shift in anti-predator behavior occurs during ...
[37]
[PDF] Contia tenuis - Garry Oak Ecosystems Recovery Team
Population sizes are unknown and difficult to estimate, as these snakes are very secretive and hard to find. Individual sharp-tailed snakes appar- ently remain ...
[38]
[PDF] BEHAVIORAL RESPONSES TO POTENTIAL PREY THROUGH ...
Abstract - The Sharp-tailed Snake (Contia tennis) ... Because of its secretive nature, little is known about its behavioral ecology. ... Behavior Category Rate ...
[39]
Adaptation to Feeding in the Snake Contia tenuis on JSTOR
Richard G. Zweifel, Adaptation to Feeding in the Snake Contia tenuis, Copeia, Vol. 1954, No. 4 (Oct. 29, 1954), pp. 299-300.
[40]
Sharp–tailed snake (Contia tenuis): COSEWIC assessment and ...
Feb 23, 2018 · Food habits. The diet of C. tenuis is thought to consist largely of small slugs (Cook 1960; Leonard and Ovaska 1998). In Oregon, Darling ...Missing: hunting | Show results with:hunting
[41]
[PDF] Sharp tailed Snake (Contia tenuis) - Wildlife, plants and species
Goal 1: Contribute to global efforts for species and ecosystem conservation. ... Conservation status report: Contia tenuis. B.C. Ministry of Environment ...
[42]
Common Sharp-tailed Snake - Canadian Herpetological Society
The eggs hatch in late summer and the young are approximately 10 cm long at hatching. This species primarily eats slugs, but earthworms, insects and salamanders ...
[43]
About Sharp Tailed Snakes - Habitat Acquisition Trust
In Canada, their known distribution is confined to southeast Vancouver Island, some of the Gulf Islands, and one location near Pemberton. There are only 17 ...
[44]
Contia tenuis Common Sharp-tailed Snake - Gov.bc.ca
Scientific Name: Contia tenuis. English Name: Common Sharp-tailed Snake. English Name Synonyms: Sharp-tailed Snake. Provincial Status Summary. Status: S1S2.
[45]
A Sharp-tailed Snake - Salt Spring Island Conservancy
Aug 28, 2024 · Sharp-tailed Snake Contia tenuis. This is a small snake, usually reddish-brown, with a thorn-like tip on the tail, a dark stipe across each ...Missing: scale | Show results with:scale
[46]
Discoveries of the Common Sharp-Tailed Snake (Contia tenuis) in ...
Feb 26, 2019 · We recorded 9 Common Sharp-tailed Snake observations between 2013 and 2017, including the 1st record for San Juan Island on Cady Mountain.
[47]
[PDF] Recovery Strategy for the Sharp-tailed Snake (Contia tenuis) in ...
Genetic material from snakes from the Gulf. Islands was donated for phylogenetic studies of Contia across its range, but DNA was obtained only from a limited ...
[48]
[PDF] Sharp tailed Snake (Contia tenuis) - Species at risk public registry
Environment and Climate Change Canada. 2017. Recovery Strategy for the. Sharp-tailed Snake (Contia tenuis) in Canada [Proposed]. Species at Risk Act Recovery.
[49]
Improving ecological surveys for the detection of cryptic, fossorial ...
The sharp-tailed snake (Contia tenuis) is a small (20–30 cm), slender, reddish-brown, non-venomous snake that is endemic to western North America, ranging from ...
[50]
https://canadianherpetology.ca/species/species_page.html?cname=Common%20Sharp-tailed%20Snake