Santiago Racer

Reptiles of Ecuador | Serpentes | Colubridae | Pseudalsophis | Pseudalsophis hephaestus

English common names: Santiago Racer, God-of-Fire Racer.

Spanish common names: Culebra de Santiago, serpiente corredora de Santiago, culebra del dios del fuego.

Recognition: ♂♂ 51.5 cm ♀♀ 53.6 cm. Pseudalsophis hephaestus is one of two snake species that occur on Santiago and Rábida islands, and probably the only one occurring on Sombrero Chino Islet. The other species is the Thomas' Racer (P. thomasi), a larger snake that does not have lateral black stripes.

Natural history: Uncommon, about ~10% as abundant as the co-occurring Thomas' Racer (Pseudalsophis thomasi). Pseudalsophis hephaestus is a diurnal snake that inhabits volcanic rock areas, dry grasslands, and deciduous forests.1 Santiago Racers are mildly venomous, which means their bite is dangerous to small prey, but not to humans.2 These snakes are foraging predators that most likely feed on Santiago Lava-Lizards (Microlophus jacobi) and leaf-toed geckos. Members of this species are active throughout most of the day, but usually not during hot midday hours. They move on soil, rocks, and shrubs.1 Individuals of P. hephaestus are preyed upon by rats.3

Reader support helps us keep the Reptiles of Ecuador book 100% free.

Conservation: Near Threatened. We consider Pseudalsophis hephaestus to be in this category following IUCN criteria4 because although the species is not undergoing a decline in the extent and quality of its habitat, it is known from only six localities and is facing the threat of predation by black rats.3 Santiago Island has a long history of introduced species, but the island's conditions are improving. Pigs were eradicated from Santiago in 1999, followed by goats in 2003, and donkeys in 2005.

Distribution: Santiago Racers are endemic to an estimated 458 km2 area on Santiago Island, Rábida Island, and Sombrero Chino Islet. Galápagos, Ecuador.

Distribution of Pseudalsophis hephaestus Distribution of Pseudalsophis hephaestus in and around Santiago Island

Etymology: The generic name Pseudalsophis, which comes from the Greek words pseudo (meaning “false”) and Alsophis (a genus of Caribbean snakes), refers to the similarity between snakes of the two genera.5 The specific epithet hephaestus is the name of the Greek god of fire and volcanoes, and refers to the volcanic environment where this species inhabits.6

See it in the wild: Like most snakes in Galápagos, Santiago Racers are secretive animals, but, with some luck, they can be seen with ~4% certainty in some tourism sites on and around Santiago Island, including Sombrero Chino Islet and Rábida Island. The best time to look for the racers is during the first hours after sunrise or right before sunset.

Authors: Alejandro ArteagaaAffiliation: Khamai Foundation, Quito, Ecuador. and Juan M GuayasaminbAffiliation: Laboratorio de Biología Evolutiva, Universidad San Francisco de Quito (USFQ), Quito, Ecuador.,cAffiliation: Galapagos Science Center, Galápagos, Ecuador.,dAffiliation: Centro de Investigación de la Biodiversidad y Cambio Climático, Universidad Tecnológica Indoamérica, Quito, Ecuador.

Academic reviewers: Robert A Thomas and Luis Ortiz-Catedral.

Photographers: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,eAffiliation: ExSitu, Quito, Ecuador.

How to cite? Arteaga A, Guayasamin JM (2020) Pseudalsophis hephaestus. In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from:

Literature cited:

  1. Field notes, Reptiles of Ecuador book project.
  2. Thomas RA (1997) Galápagos terrestrial snakes: biogeography and systematics. Herpetological Natural History 5: 19–40.
  3. Fritts TH, Fritts PR (1982) Race with extinction: herpetological notes of J. R. Slevin's journey to the Galápagos 1905–1906. Herpetological Monographs 1: 1–98.
  4. IUCN (2001) IUCN Red List categories and criteria: Version 3.1. IUCN Species Survival Commission, Gland and Cambridge, 30 pp.
  5. Zaher H, Grazziotin FG, Cadle JE, Murphy RW, Moura-Leite JC, Bonatto SL (2009) Molecular phylogeny of advanced snakes (Serpentes, Caenophidia) with an emphasis on South American Xenodontines: a revised classification and descriptions of new taxa. Papéis Avulsos de Zoologia 49: 115–153.
  6. Zaher H, Yánez-Muñoz MH, Rodrigues MT, Graboski R, Machado FA, Altamirano-Benavides M, Bonatto SL, Grazziotin F (2018) Origin and hidden diversity within the poorly known Galápagos snake radiation (Serpentes: Dipsadidae). Systematics and Biodiversity 16: 614–642.