Shrubland Snail-Eater

Reptiles of Ecuador | Serpentes | Colubridae | Dipsas | Dipsas jamespetersi

English common names: Shrubland Snail-Eater.

Spanish common names: Caracolera de matorral.

Recognition: ♂♂ 81.9 cm ♀♀ 77.1 cm. In its area of distribution, the Shrubland Snail-Eater (Dipsas jamespetersi) can be identified based on its brown or grayish brown body with 29–59 dark crossbands, enlarged vertebral scale row, and presence of a preocular scale.1 The most similar snake species occurring alongside D. jamespetersi in Ecuador are D. oligozonata and D. oreas, but none of these snakes have a preocular scale.1

Natural history: Rare to uncommon. Dipsas jamespetersi is a primarily crepuscular and nocturnal snake that inhabits pristine to heavily disturbed humid and dry montane shrublands, high evergreen montane forests, rural gardens, houses, and areas of mixed pasture, agricultural land, and forest remnants.13 Shrubland Snail-Eaters are mostly terrestrial,3,4 but they also move actively on shrubs up to 3 m above the ground.5 In captivity, individuals of D. jamespetersi feed exclusively on slugs, and reject other prey items such as tadpoles and lizards.6 In the wild, they are most common in areas where slugs are abundant.4 During the day, snakes of this species rest coiled inside bromeliads,5 at the base of agave plants,1 or under rocks and logs.1 Shrubland Snail-Eaters are harmless to humans; they are extremely docile and never attempt to bite.7 If threatened, individuals may coil into a defensive posture and produce a musky and distasteful odor.7 Members of this species are preyed upon by coralsnakes (Micrurus mertensi).1 Females lay 5 eggs per clutch.1

Conservation: Near Threatened. We consider Dipsas jamespetersi to be in this category, instead of Least Concern,8 following IUCN criteria,9 because much of the species' natural habitat has been fragmented or destroyed. In Ecuador, we estimate that ~63.5% of the habitat of this species has been lost. The patches of shrubland and montane forest vegetation where the species occurs are too few, moderately to heavily disturbed, and lack connectivity between them. Live individuals of D. jamespetersi are rarely encountered, but are commonly seen dead on roads, which may indicate a high rate of mortality from vehicle traffic. We anticipate that D. jamespetersi may qualify for a threatened category in the near future if the species' habitat continues to be degraded.

Distribution: Dipsas jamespetersi occurs in the inter-Andean valleys and both slopes of the Andes in southern Ecuador and northern Peru. Although the area of distribution of D. jamespetersi in Ecuador is ~5,512 km2, we estimate that only an area of ~2,008 km2 holds habitat where the species might occur.

Distribution of Dipsas jamespetersi in Ecuador

Etymology: The generic name Dipsas, which comes from the Greek word dipsa (meaning “thirst”),10 probably refers to the fact that the bite of these snakes was believed to cause intense thirst. The specific epithet jamespetersi honors American herpetologist James A Peters (1922–1972), in recognition of his contributions to expanding the knowledge on Neotropical reptiles, particularly those from Ecuador.2

See it in the wild: Shrubland Snail-Eaters are recorded rarely, usually no more than once every few months at any given locality. However, there are some areas, like along the Vilcabamba–Palanda road, Loja province, and in the vicinity of Nabón and Oña, Azuay province, where individuals are seen more frequently. The snakes are may be spotted as they cross trails and roads in areas of highland shrubland, especially around sunset.

FAQ

Do snails attract snakes? Yes. Snail-eating snakes follow snails visually or by tracking their scent trail.11

Do snail-eating snakes eat the shell of the snails? They don't. These snakes use specialized muscular contractions of their wedge-like head to extract snails from their shells.11

Author: Alejandro ArteagaaAffiliation: Biodiversity Field Lab, Khamai Foundation, Quito, Ecuador.

Photographer: Alejandro ArteagaaAffiliation: Tropical Herping (TH), Quito, Ecuador.

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

Literature cited:

  1. Cadle JE (2007) The snake genus Sibynomorphus (Colubridae: Dipsadinae: Dipsadini) in Peru and Ecuador, with comments on the systematics of Dipsadini. Bulletin of the Museum of Comparative Zoology 158: 183–283.
  2. Orcés G, Almendáriz A (1989) Presencia en el Ecuador de los colúbridos del género Sibynomorphus. Revista Politécnica: 57–67.
  3. Field notes of Pablo Loaiza.
  4. Field notes of Jorge Luis Romero.
  5. Field notes of Juan Carlos Sánchez.
  6. Field notes of Ernesto Arbeláez.
  7. Field notes, Reptiles of Ecuador book project.
  8. Cisneros-Heredia DF, Brito J, Yánez-Muñoz MH (2019) Dipsas jamespetersi. The IUCN red list of threatened species. Available from: www.iucnredlist.org
  9. IUCN (2001) IUCN Red List categories and criteria: Version 3.1. IUCN Species Survival Commission, Gland and Cambridge, 30 pp.
  10. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.
  11. Sheehy C (2012) Phylogenetic relationships and feeding behavior of Neotropical snail-eating snakes (Dipsadinae, Dipsadini). PhD Thesis, UT Arlington.