Published December 25, 2020. Updated February 29, 2024. Open access.

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White-naped Ground Snake (Atractus occipitoalbus)

Reptiles of Ecuador | Serpentes | Colubridae | Atractus occipitoalbus

English common names: White-naped Ground Snake, White-capped Ground Snake, Grey Ground Snake.

Spanish common name: Tierrera de collar blanco.

Recognition: ♂♂ 21.6 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=19.7 cm. ♀♀ 26.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=27.8 cm..1,2 Atractus occipitoalbus can be recognized by having a round head similar in width to the neck, small eyes, uniformly dark brown dorsum and belly, a light nape band, and smooth dorsal scales (Fig. 1).1,2 The two Amazonian ground snakes that most resemble A. occipitoalbus in coloration are A. collaris and A. orcesi, but none of these species has an entirely dark brown belly.3 The Amazon Coffee-Snake (Ninia hudsoni) also has a uniformly dark dorsum, but it has a cream-colored belly and keeled dorsal scales.1

Figure showing a juvenile individual of Atractus occipitoalbus

Figure 1: Juvenile of Atractus occipitoalbus from Macas, Morona Santiago province, Ecuador.

Natural history: Atractus occipitoalbus is a rarely seen semi-fossorial snake that inhabits old-growth to moderately disturbed rainforests, but may as well occur in forest edges and inside houses.1,4,5 White-naped Ground Snakes have been observed moving on the forest floor at night6,7 as well as during the day.8 Inactive individuals have been found hidden under rocks and logs.1,5,6 Earthworms have been reported in the diet of A. occipitoalbus,1 and parasitic roundworms have been detected in the intestines of Ecuadorian individuals,9 but their effect on their host is not clear. The defensive behavior in the White-naped Ground Snake consists of trying to flee and hide.4 One gravid female found in May in Ecuador contained three eggs.1 The smallest juveniles have been found between May and July.1 However, the real clutch size and the reproductive season are still unknown.

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..10 Atractus occipitoalbus is proposed to be included in this category, instead of Near Threatened,11 because current information suggests that the species is distributed over an area greater than 61,000 km2 in a region that retains the majority of its original forest cover. Approximately 80.6% of the species’ area of distribution in Ecuador still holds continuous rainforest habitat. Atractus occipitoalbus also occurs in large protected areas such as Yasuní National Park, Sangay National Park, and Cayambe Coca National Park. The most important threat to the long-term survival of some populations of A. occipitoalbus is forest destruction due to the expansion of the agricultural frontier, the construction of roads through pristine habitats, large-scale mining, and hydroelectric projects.11

Distribution: Atractus occipitoalbus is native to the Amazonian lowlands and adjacent Andean foothills of Ecuador (Fig. 2) and Colombia. There are records of A. occipitoalbus in Bolivia5 and west of the Andes in Colombia,7 but it is still unclear if these correspond to the same species.

Distribution of Atractus occipitoalbus in Ecuador

Figure 2: Distribution of Atractus occipitoalbus 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 (=spindle),1214 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 occipitoalbus is composed by the Latins words occiput (=back of the head) and albus (=light-colored), and refers to the white nape band.

See it in the wild: White-naped Ground Snakes are seen rarely, usually no more than once every few months. Some localities with recent records of this species are Río Bigal Biological Reserve, Orellana Province, and Macas, Morona Santiago province. The snakes can be detected by scanning the forest floor and leaf-litter along trails at night.

Acknowledgments: Special thanks to Jean Merino for finding the specimen of Atractus occipitoalbus photographed in this account.

Authors: Duvan ZambranoaAffiliation: Universidad del Tolima, Ibagué, Colombia. and Alejandro ArteagabAffiliation: Tropical Herping (TH), Quito, Ecuador.

Photographer: Jose VieiracAffiliation: Tropical Herping (TH), Quito, Ecuador.,dAffiliation: ExSitu, Quito, Ecuador.

How to cite? Zambrano D, Arteaga A (2024) White-naped Ground Snake (Atractus occipitoalbus). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/SYJZ7591

Literature cited:

  1. Duellman WE (1978) The biology of an equatorial herpetofauna in Amazonian Ecuador. Publications of the Museum of Natural History, University of Kansas 65: 1–352.
  2. Passos P, Chiesse A, Torres-Carvajal O, Savage JM (2009) Testing species boundaries within the Atractus occipitoalbus complex (Serpentes: Dipsadidae). Herpetologica 65: 384–403. DOI: 10.1655/08-024.1
  3. Savage JM (1960) A revision of the Ecuadorian snakes of the Colubrid genus Atractus. Miscellaneous Publications, Museum of Zoology, Univesity of Michigan 112: 1–184.
  4. Field notes, Reptiles of Ecuador book project.
  5. Quinteros-Muñoz O (2013) Serpentes, Dipsadidae, Atractus occipitoalbus: second record and distribution extension in Bolivia. Check List 9: 76–77. DOI: 10.15560/9.1.76
  6. Silva Haad J (2004) Las serpientes del género Atractus Wagler, 1828 (Colubridae, Xenodontinae) en la Amazonia colombiana. Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 28: 409–446.
  7. Marín CM, Toro FA, Daza JM (2017) First trans-Andean record of Atractus occipitoalbus (Jan, 1862), (Squamata, Dipsadidae), from Colombia. Herpetology Notes 10: 49–51.
  8. Jhomy Valera, pers. comm.
  9. McAllister CT, Bursey CR, Freed PS (2010) Helminth parasites of selected amphibians and reptiles from the Republic of Ecuador. Comparative Parasitology 77: 52–66. DOI: 10.1654/4402.1
  10. Reyes-Puig C (2015) Un método integrativo para evaluar el estado de conservación de las especies y su aplicación a los reptiles del Ecuador. MSc thesis, Pontificia Universidad Católica del Ecuador, 73 pp.
  11. Cisneros-Heredia DF, Ortega A (2016) Atractus occipitoalbus. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2016-1.RLTS.T44581256A44581265.en
  12. 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.
  13. Beekes R (2010) Etymological dictionary of Greek. Brill, Boston, 1808 pp.
  14. 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 occipitoalbus in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

ColombiaCaquetáFlorencia, El ParaísoPassos et al. 2009
ColombiaCaucaSanta RosaPassos et al. 2009
ColombiaPutumayoEl OritoPassos et al. 2009
EcuadorMorona SantiagoChanala–Macas trailSavage 1960
EcuadorMorona SantiagoChiguazaPassos et al. 2009
EcuadorMorona SantiagoChiguaza and Macuma, betweenPassos et al. 2009
EcuadorMorona SantiagoMacasThis work
EcuadorMorona SantiagoMéndezPassos et al. 2009
EcuadorMorona SantiagoPaloraThis work
EcuadorMorona SantiagoSucúaUSNM 232698
EcuadorNapoJatun Sacha Biological StationMCZ 173832
EcuadorNapoNarupayacuPhoto by José Simbaña
EcuadorOrellanaLoretoPassos et al. 2009
EcuadorOrellanaPozo Tivacuno APhoto by Morley Read
EcuadorOrellanaRío Bigal Biological ReservePhoto by Thierry García
EcuadorOrellanaSan José de PayaminoMaynard et al. 2017
EcuadorPastazaAbitaguaSavage 1960
EcuadorPastazaAlto BobonazaPassos et al. 2009
EcuadorPastazaAlto CurarayPassos et al. 2009
EcuadorPastazaBobonaza, region ofUSNM 234812
EcuadorPastazaBosque Protector Yawa JeeMcAllister et al. 2010
EcuadorPastazaCabeceras del Río BobonazaUSNM 234814
EcuadorPastazaComunidad TarangaroOnline multimedia
EcuadorPastazaHacienda San FranciscoSavage 1960
EcuadorPastazaOglán AltoPassos et al. 2009
EcuadorPastazaPastaza RiverMCZ 36955
EcuadorPastazaPuyo–Tarqui, km 15iNaturalist
EcuadorPastazaPuyo, calle Alberto ZambranoiNaturalist
EcuadorPastazaPuyo, Hosteria TuringiaPassos et al. 2009
EcuadorPastazaRío Arajuno, headwaters ofPassos et al. 2009
EcuadorPastazaRío VillanoPassos et al. 2009
EcuadorPastazaSantanaPassos et al. 2009
EcuadorPastazaUNOCAL Base CampUSNM 321109
EcuadorPastazaVía Pompeya Sur–IroPhoto by Morley Read
EcuadorPastazaVillanoSavage 1960
EcuadorSucumbíosLago AgrioKU 126001
EcuadorSucumbíosPuerto LibrePassos et al. 2009
EcuadorSucumbíosSanta CeciliaPassos et al. 2009