Published September 2, 2021. Open access.

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Red-naped Ground Snake (Atractus clarki)

Reptiles of Ecuador | Serpentes | Colubridae | Atractus | Atractus clarki

English common names: Red-naped Ground Snake, Clark’s Ground Snake.

Spanish common names: Tierrera de collar rojo, culebra tierrera de Clark.

Recognition: ♂♂ 35.1 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=30 cm. ♀♀ 39.6 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=35.4 cm..1 The Red-naped Ground Snake (Atractus clarki) differs from other snakes in its area of distribution by having a round head similar in width to the neck, small eyes, dorsal pattern consisting of broad (4–7 dorsal scales wide) black bands separated by narrow (1–2 dorsal scales wide) whitish bands, and a red band on the neck.1,2 The bands do not encircle the body and the belly is entirely red.1,2 This characteristic separates A. clarki from the true coral snake species it mimics: Micrurus mipartitus.3 Atractus clarki is similar to A. multicinctus, a species in which the body bands are red, and in which the males have more than 170 ventral scales (versus less than 170 in A. clarki).1

Figure showing variation among adult individuals of Atractus clarki

Figure 1: Individuals of Atractus clarki from Morromico, Chocó department, Colombia (); and Canandé Reserve, Esmeraldas province, Ecuador ().

Natural history: UncommonUnlikely to be seen more than once every few months.. Atractus clarki is a semi-fossorial (living underground and at ground level) snake that inhabits old-growth to moderately disturbed evergreen lowland forests.4 The species also occurs in areas having a matrix of pastures, rural houses, and remnants of native vegetation.5,6 Red-naped Ground Snakes are nocturnal. Individuals have been seen moving on the forest floor, crossing trails and dirt roads, or inside houses.4,5 It is presumed that individuals of A. clarki rely on their warning coloration as a primary defense mechanism. There is an unpublished photographic record of a member of this species preying upon a giant earthworm.7

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..8 Atractus clarki is listed in this category because the species is widely distributed throughout the lowlands of the Chocó and Río Magdalena valley regions, especially in areas that have not been heavily affected by deforestation, such as the Colombian Pacific coast. As a result, the species is unlikely to be declining fast enough to qualify for a more threatened category.8 In Ecuador, five of the six records (Appendix 1) are in protected areas, but populations elsewhere may disappear due to large-scale deforestation. Vehicular traffic and the fear of snakes is also a source of mortality to individuals of this species. People in rural regions tend to kill any snake, particularly those that resemble a coral snake.4

Distribution: Atractus clarki is native to the lowlands and adjacent mountain foothills of the Chocó and Río Magdalena valley regions from eastern Panama, through Colombia, to northwestern Ecuador. In Ecuador, the species occurs at elevations between 146 and 463 m (Fig. 2).

Distribution of Atractus clarki in Ecuador

Figure 2: Distribution of Atractus clarki in Ecuador. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The name Atractus, which is a latinization of the Greek word άτρακτος (meaning “spindle”),911 probably refers to the fact that snakes of this genus have a uniform width throughout the body and a narrow tail, resembling an antique spindle used to spin fibers. The specific epithet clarki honors American pathologist and researcher Herbert C. Clark (1877–1960), first director of the Gorgas Memorial Laboratory and instigator of the Panamanian snake census, which contributed immensely to knowledge of the snake fauna of Panama.2

See it in the wild: In Ecuador, Red-naped Ground Snakes are unlikely to be seen more than once every few months at any given locality. The only locality in Ecuador having more than one record of this species is Bilsa Biological Reserve, Esmeraldas province. The snakes may be located by scanning the forest floor and leaf-litter along trails at night or by looking under rocks and logs in pastures nearby forest border.

Special thanks to Frederic Griesbaum for symbolically adopting the Red-naped Ground Snake and helping bring the Reptiles of Ecuador book project to life.

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Acknowledgments: This account was published with the support of Secretaría Nacional de Educación Superior Ciencia y Tecnología (programa INEDITA; project: Respuestas a la crisis de biodiversidad: la descripción de especies como herramienta de conservación; No 00110378), Programa de las Naciones Unidas (PNUD), and Universidad San Francisco de Quito (USFQ).

Author: Alejandro ArteagaaAffiliation: Khamai Foundation, Quito, Ecuador.

Photographers: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador. and Sebastián Di DoménicocAffiliation: Keeping Nature, Bogotá, Colombia.

How to cite? Arteaga A (2021) Red-naped Ground Snake (Atractus clarki). In: Arteaga A, Bustamante L, Vieira J, Guayasamin JM (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/VXZQ6754

Literature cited:

  1. Passos P, Mueses-Cisneros JJ, Lynch JD, Fernandes R (2009) Pacific lowland snakes of the genus Atractus (Serpentes: Dipsadidae), with description of three new species. Zootaxa 2293: 1–34. DOI: 10.5281/zenodo.191476
  2. Myers CW (2003) Rare snakes—Five new species from eastern Panama: reviews of northern Atractus and southern Geophis (Colubridae: Dipsadinae). American Museum Novitates 3391: 1–47.
  3. Valencia JH, Garzón-Tello K, Barragán-Paladines ME (2016) Serpientes venenosas del Ecuador: sistemática, taxonomía, historial natural, conservación, envenenamiento y aspectos antropológicos. Fundación Herpetológica Gustavo Orcés, Quito, 653 pp.
  4. Field notes, Reptiles of Ecuador book project.
  5. Photo by Santiago Ayerbe.
  6. Photo by Blair Dudeck.
  7. Photo by Raúl Nieto.
  8. Ibáñez R, Jaramillo C, Velasco J, Bolívar W, Castañeda MR (2017) Atractus clarki. The IUCN red list of threatened species. Available from: DOI: 10.2305/IUCN.UK.2017-2.RLTS.T203431A2765413.en
  9. Woodward SP, Tate R (1830) A manual of the Mollusca: being a treatise on recent and fossil shells. C. Lockwood and Company, London, 750 pp.
  10. Beekes R (2010) Etymological dictionary of Greek. Brill, Boston, 1808 pp.
  11. Duponchel P, Chevrolat L (1849) Atractus. In: d’Orbigny CD (Ed) Dictionnaire universel d'histoire naturelle. MM. Renard, Martinet et Cie., Paris, 312.

Appendix 1: Locality data used to create the distribution map of Atractus clarki in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

EcuadorCotopaxiEl Jardín de los SueñosPhoto by Christophe Pellet
EcuadorEsmeraldasBilsa Biological ReserveOrtega-Andrade et al. 2010
EcuadorEsmeraldasCanandé ReserveThis work
EcuadorEsmeraldasItapoa ReservePhoto by Rául Nieto
EcuadorPichincha Puerto Quito, 1 km W ofiNaturalist