Published May 12, 2018. Updated April 8, 2024. Open access.

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Short-banded Snail-eating Snake (Dipsas oligozonata)

Reptiles of Ecuador | Serpentes | Colubridae | Dipsas oligozonata

English common name: Short-banded Snail-eating Snake.

Spanish common name: Caracolera de bandas cortas.

Recognition: ♂♂ 76.6 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=63.2 cm. ♀♀ 77.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=61.8 cm..1 Dipsas oligozonata can be identified by lacking a preocular scale and having a light brown dorsum with complete bold dark crossbands only on the anterior half of the body (Fig. 1).13 This species further differs from D. jamespetersi by having an immaculate or lightly spotted belly and a lower number of supralabial scales (6–7 vs 8).2,3 From D. oreas, it differs by lacking bold elliptical blotches along the entire length of the body.4

Figure showing variation among individuals of Dipsas oligozonata

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

Natural history: Dipsas oligozonata is a crepuscular and nocturnal snake that inhabits montane shrublands, highland grasslands, and high evergreen montane forests, occurring in lower densities in plantations and rural gardens.36 Short-banded Snail-Eaters are terrestrial and most active between 6:30 and 10:00 pm.36 During the day, they have been found hidden between weeds, under trunks, or among piled leaves.6 The diet in this species consists of snails, slugs, and soft-bodied insects.2,6 The mollusks are presumably immobilized by the use of toxins secreted by the mucous cells of the infralabial glands.7 Nevertheless, all snakes in the genus Dipsas are considered harmless to humans. They never attempt to bite, resorting instead to coiling into a defensive ball posture and producing a musky and distasteful odor when threatened.5,8 The clutch size in D. oligozonata consists of 4 eggs.9

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Conservation: Endangered Considered to be facing a high risk of extinction in the near future.. Dipsas oligozonata is proposed to be listed in this category, instead of in Vulnerable,10 because the species is restricted to an extremely small area where approximately 62% of the native vegetation cover has been destroyed. Based on Fig. 2, it es estimated that, in total, there is no more than ~544 km2 of suitable habitat remaining for D. oligozonata. Furthermore, the species occurs as fragmented populations and there is continuing decline in the extent and quality of its shrubland habitat.10 Short-banded Snail-eating Snakes are rarely encountered but are commonly seen dead on roads,11 which may indicate a high rate of mortality from vehicular traffic.

Distribution: Dipsas oligozonata is endemic to an area of approximately 1,425 km2 along the headwaters of the Río Jubones in the southwestern slopes of the Andes in Ecuador (Fig. 2).

Distribution of Dipsas oligozonata in Ecuador

Figure 2: Distribution of Dipsas oligozonata in Ecuador. The star corresponds to the type locality: Zhila, Azuay province. 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)12 and probably refers to the fact that the bite of these snakes was believed to cause intense thirst. The specific epithet oligozonata comes from the Greek words oligo (=few), zona (=belt), and the suffix -atus (=provided with).12 It refers to the low number of complete transverse bands.3

See it in the wild: Short-banded Snail-Eaters are recorded rarely, usually no more than once every few weeks at any given locality. However, there are some areas, like around the towns Susudel and Oña, where individuals are seen more frequently, especially around sunset as they cross trails and roads in areas of highland shrubland.

Acknowledgments: Special thanks to Jorge Luis Romero for providing novel natural history data on Dipsas oligozonata.

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) Short-banded Snail-eating Snake (Dipsas oligozonata). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/IIXV1820

Literature cited:

  1. 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
  2. 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
  3. Orcés G, Almendáriz A (1989) Presencia en el Ecuador de los colúbridos del género Sibynomorphus. Revista Politécnica: 57–67.
  4. 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.
  5. Field notes, Reptiles of Ecuador book project.
  6. Field notes of Jorge Luis Romero.
  7. De Oliveira L, Jared C, da Costa Prudente AL, Zaher H, Antoniazzi MM (2008) Oral glands in dipsadine “goo-eater” snakes: morphology and histochemistry of the infralabial glands in Atractus reticulatus, Dipsas indica, and Sibynomorphus mikanii. Toxicon 51: 898–913. DOI: 10.1016/j.toxicon.2007.12.021
  8. 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.
  9. Field notes of Ernesto Arbeláez.
  10. Brito J, Cisneros-Heredia DF, Yánez-Muñoz M (2019) Dipsas oligozonata. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-3.RLTS.T48617612A48617614.en
  11. Juan Carlos Sánchez, pers. comm. to AA.
  12. 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 oligozonata in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

EcuadorAzuayCorralejaThis work; Fig. 1
EcuadorAzuayEl ProgresoJorge Luis Romero, pers. comm.
EcuadorAzuayGirónArteaga et al. 2018
EcuadorAzuayGranja Orgánica SusudelArteaga et al. 2018
EcuadorAzuayLa GritaReptiles of Ecuador book database
EcuadorAzuayLa PazJorge Luis Romero, pers. comm.
EcuadorAzuayLa RetoñaJorge Luis Romero, pers. comm.
EcuadorAzuayOñaOrces & Almendáriz 1989
EcuadorAzuayPoetateThis work; Fig. 1
EcuadorAzuaySanta Isabel, 6 km W ofCadle 2007
EcuadorAzuaySusudelArteaga et al. 2018
EcuadorAzuayVia a ShaglliArteaga et al. 2018
EcuadorAzuayVía Susudel–PoetatePazmiño-Otamendi 2020
EcuadorAzuayZhila*Orcés & Almendáriz 1989
EcuadorLojaSaraguroJorge Luis Romero, pers. comm.