Published May 12, 2018. Updated April 9, 2024. Open access.

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Mountain Snail-eating Snake (Dipsas oreas)

Reptiles of Ecuador | Serpentes | Colubridae | Dipsas oreas

English common name: Mountain Snail-eating Snake.

Spanish common name: Caracolera montañera.

Recognition: ♂♂ 78.5 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=54.3 cm. ♀♀ 82.7 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=62.6 cm..1 Dipsas oreas can be identified by lacking a preocular scale and by having a grayish or brownish dorsum with 17–30 dark oval to elliptical dorsolateral blotches that form complete bands on the anterior part of the body (Fig. 1).1,2 This species differs from D. andiana by having blotches that form complete bands on the anterior part of the body and by lacking a clearly defined dark ∩-shaped mark on the back of the head.1,3 From D. jamespetersi and D. oligozonata, it differs by having oval or elliptical blotches instead of dorsal crossbands.4

Figure showing variation among individuals of Dipsas oreas

Figure 1: Individuals of Dipsas oreas from Corraleja () and Girón (), Azuay province, Ecuador.

Natural history: Dipsas oreas is a nocturnal snake that inhabits montane shrublands, montane forests, and cloud forests, occurring also in crops and in pastures with scattered trees.1,5 Mountain Snail-Eaters are active at night, especially during the rainy season (December–May) or whenever it is raining or drizzling,1,5 with most activity occuring at ground level or on low (0.15–2.3 m) vegetation.1,5,6 The increased foraging during humid periods is probably related to their diet, which consists of slugs and snails.1,5 During the day, these snakes have been found coiled under rocks, beneath leaf-litter, or in crevices and bromeliads.1,5 The Mountain Snail-Eater, when threatened, typically responds by musking, flattening the body, coiling into a defensive posture, and expanding the head to simulate a triangular shape.1,5 Aggregations of seven individuals of D. oreas (one female and six males), presumably related to mating, have been reported.1,5 Females lay clutches of 3–8 eggs in communal nesting sites such as in crevices 5–30 cm underground.5,7

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Conservation: Near Threatened Not currently at risk of extinction, but requires some level of management to maintain healthy populations..8 Dipsas oreas is listed in this category because the majority of the species’ natural habitat is fragmented and continues to decline in extent and quality due to the expansion of the agricultural frontier.6,8 In Ecuador, approximately 64% of the habitat of this species has been destroyed.9 The patches of shrubland vegetation where Mountain Snail-Eaters occur are too few, heavily disturbed, and lack connectivity between them.6,8 Individuals of D. oreas are commonly seen dead on roads, which may indicate a high rate of mortality from vehicular traffic.5 Therefore, the species could qualify for a threatened category in the near future if its habitat continues to be degraded.

Distribution: Dipsas oreas is native to the inter-Andean valleys and both slopes of the Andes in southern Ecuador (Fig. 2) and northern Peru. Although the area of distribution of D. oreas in Ecuador is approximately 21,246 km2 probably only about 7,660 km2 holds habitat where the species might persist.

Distribution of Dipsas oreas in Ecuador

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

Etymology: The name Dipsas comes from the Greek dipsa (=thirst)10 and probably refers to the fact that the bite of these snakes was believed to cause intense thirst. The specific epithet oreas comes from the Greek word oros (=mountain)10 and refers to the distribution of the species.

See it in the wild: Mountain Snail-eating Snakes can be seen at a rate of about once every few nights, especially during the rainy season in western Ecuador (Dec–May). Prime localities for the species include the valleys of Girón and Vilcabamba.

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

Photographer: Jose VieirabAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador.

How to cite? Arteaga A (2024) Mountain Snail-eating Snake (Dipsas oreas). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/OMHJ8000

Literature cited:

  1. Cadle JE (2005) Systematics of snakes in the Dipsas oreas complex (Colubridae: Dipsadinae) in western Ecuador and Peru, with revalidation of D. elegans (Boulenger) and D. ellipsifera (Boulenger). Bulletin of the Museum of Comparative Zoology 158: 67–136.
  2. Arteaga A, Salazar-Valenzuela D, Mebert K, Peñafiel N, Aguiar G, Sánchez-Nivicela JC, Pyron RA, Colston TJ, Cisneros-Heredia DF, Yánez-Muñoz MH, Venegas PJ, Guayasamin JM, Torres-Carvajal O (2018) Systematics of South American snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Ecuador and Peru. ZooKeys 766: 79–147. DOI: 10.3897/zookeys.766.24523
  3. Cadle JE, Myers CW (2003) Systematics of snakes referred to Dipsas variegata in Panama and Western South America, with revalidation of two species and notes on defensive behaviors in the Dipsadini (Colubridae). American Museum Novitates 3409: 1–47.
  4. 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. DOI: 10.3099/0027-4100(2007)158[183:TSGSCD]2.0.CO;2
  5. Field notes, Reptiles of Ecuador book project.
  6. Almendáriz A (2007) Primer registro de Dipsas oreas en la provincia del Azuay, Ecuador. Revista Politécnica 27: 136–137.
  7. Cadle JE, Chuna P (1995) A new lizard of the genus Macropholidus (Teiidae) from a relictual humid forest of northwestern Peru, and notes on Macropholidus ruthveni Noble. Breviora 501: 1–39.
  8. Yánez-Muñoz M, Venegas P, Cisneros-Heredia DF (2017) Dipsas oreas. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2017-2.RLTS.T50951300A50951309.en
  9. MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
  10. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.

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

EcuadorAzuayChorros de GirónReptiles of Ecuador book database
EcuadorAzuayCorralejaThis work; Fig. 1
EcuadorAzuayCuencaErnesto Arbeláez, pers. comm.
EcuadorAzuayCumbeArteaga et al. 2018
EcuadorAzuayFlor y SelvaMZUA.RE.0119; examined
EcuadorAzuayGirónThis work; Fig. 1
EcuadorAzuayLuz MaríaArteaga et al. 2018
EcuadorAzuayMolleturoErnesto Arbeláez, pers. comm.
EcuadorAzuayNoramboteReptiles of Ecuador book database
EcuadorAzuayReserva Biológica YunguillaArteaga et al. 2018
EcuadorAzuaySan Rafael de SharugArteaga et al. 2018
EcuadorAzuayTrincheras de ErnestoAlmedáriz 2007
EcuadorAzuayTurupambaErnesto Arbeláez, pers. comm.
EcuadorChimborazoAlausíDespax 1911
EcuadorChimborazoHuigraCadle & Myers 2003
EcuadorChimborazoMultitudArteaga et al. 2018
EcuadorChimborazoPallatangaOrton 1867
EcuadorChimborazoValle del ChanchánCadle & Myers 2003
EcuadorEl OroLote ReinieroReptiles of Ecuador book database
EcuadorEl OroPlaya LimónArteaga et al. 2018
EcuadorEl OroRemolinoGarzón-Santomaro et al. 2019
EcuadorEl OroReserva Biológica BuenaventuraArteaga et al. 2018
EcuadorEl OroZarumaOnline multimedia
EcuadorLojaAmaluzaiNaturalist; photo examined
EcuadorLojaCatacocha, 20 Km NE ofCadle & Myers 2003
EcuadorLojaCatamayoAlmendáriz 2007
EcuadorLojaCazerío BalzonesArteaga et al. 2018
EcuadorLojaGuacarrumiiNaturalist; photo examined
EcuadorLojaJimburaArteaga et al. 2018
EcuadorLojaJorupeReptiles of Ecuador book database
EcuadorLojaLojaPhoto by Felix Fleck
EcuadorLojaMasanamacaArteaga et al. 2018
EcuadorLojaQuilangaiNaturalist; photo examined
EcuadorLojaRío CatamayoCadle 2005
EcuadorLojaRumi WilcoiNaturalist; photo examined
EcuadorLojaSan Antonio, 1 km W ofiNaturalist; photo examined
EcuadorLojaSan Pedro, 33 km E ofArteaga et al. 2018
EcuadorLojaSaraque, 1.7 km SE ofiNaturalist; photo examined
EcuadorLojaVelacruzCadle 2005
EcuadorLojaVía al Cerro ToledoArteaga et al. 2018
EcuadorLojaVilcabambaArteaga et al. 2018
EcuadorZamora ChinchipeSan AndrésTorres-Carvajal et al. 2019
PeruCajamarcaRío Zaña study siteCadle 2005
PeruLambayequeLimón, 6 km S ofiNaturalist; photo examined
PeruPiuraAyabacaCadle 2005
PeruPiuraCanchaque, 15 km E ofCadle 2005
PeruPiuraCerro AypateCadle 2005
PeruPiuraPorculla, 2 km W ofCadle 2005
PeruPiuraToroncheCadle 2005