Published May 12, 2018. Updated April 10, 2024. Open access.

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Palmer’s Snail-eating Snake (Dipsas palmeri)

Reptiles of Ecuador | Serpentes | Colubridae | Dipsas palmeri

English common name: Palmer’s Snail-eating Snake.

Spanish common name: Caracolera de Palmer.

Recognition: ♂♂ 129.7 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=90.7 cm. ♀♀ 118.7 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=88.9 cm..1 Dipsas palmeri is the only snake in its area of distribution having a light brown dorsum with 32–41 brown to blackish white-edged circular blotches and no white transverse line on the snout (Fig. 1).1 The head is black with different degrees of whitish edging on the labial scales. This species differs from D. catesbyi by having a loreal scale in contact with the orbit as well as by lacking a white transverse line on the snout.2,3 From D. pavonina, it differs by having blotches that are narrower near the top of the dorsum.3

Figure showing variation among individuals of Dipsas palmeri

Figure 1: Individuals of Dipsas palmeri from Ecuador: Guayzimi Alto, Zamora Chinchipe province (); Las Tablas, Morona Santiago province (). j=juvenile.

Natural history: Dipsas palmeri is a nocturnal snake that inhabits evergreen montane forests and cloud forests, occurring also in forest edges, pastures, and rural gardens.1,4 Palmer’s Snail-Eaters are semi-arboreal, being active both on low (less than 3.5 m above the ground) vegetation as well as at ground level, with many individuals seen crossing roads in rural areas at dusk.1,4 During the day, these snakes remain coiled under the leaf-litter.4 Nothing is know about the diet in this species, but snakes of the genus Dipsas in general feed almost exclusively on snails and slugs. Although some snail-eaters produce saliva that is toxic to mollusks,5 these snakes are considered harmless to humans. They never attempt to bite, resorting instead to musking and flattening the body while expanding the head to simulate a triangular shape.4,6

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Conservation: Least Concern Believed to be safe from extinction given current circumstances.. Dipsas palmeri is a recently revalidated species.1 Therefore, it has not been formally evaluated by the IUCN Red List. Here, it is provisionally assigned to the LC category because the species has a wide distribution spanning many protected areas. More than half of the 51 known localities of occurrence of the species are within the limits of protected areas or their buffer zones. However, individuals of D. palmeri are commonly seen dead on roads,4 which may indicate a high rate of mortality from vehicular traffic.

Distribution: Dipsas palmeri is native to the Amazonian slopes of the Andes in eastern Ecuador (Fig. 2) and northeastern Peru.

Distribution of Dipsas palmeri in Ecuador

Figure 2: Distribution of Dipsas palmeri in Ecuador. The star corresponds to the type locality: El Topo, Tungurahua 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)7 and probably refers to the fact that the bite of these snakes was believed to cause intense thirst. The specific epithet palmeri honors Mervyn George Palmer (1882–1954), an English naturalist who collected the holotype.8

See it in the wild: Palmer’s Snail-eating Snakes can be seen at a rate of about once every few nights, especially after a warm day in forested areas around the town Baños de Agua Santa. The snakes are most easily found by cruising along dirt roads shortly after sunset.

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

Photographers: Jose VieirabAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador. and Amanda QuezadaaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: Khamai Foundation, Quito, Ecuador.

How to cite? Arteaga A (2024) Palmer’s Snail-eating Snake (Dipsas palmeri). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/MCMO1025

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. Peters JA (1956) An analysis of variation in a South American snake, Catesby’s Snail-Sucker (Dipsas catesbyi Sentzen). American Museum Novitates: 1–41.
  3. 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.
  4. Field notes of Diego Piñán and Fernando Vaca.
  5. 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
  6. 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.
  7. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.
  8. Boulenger GA (1912) Descriptions of new reptiles from the Andes of South America, preserved in the British Museum. Annals and Magazine of Natural History 10: 420–424.

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

EcuadorAzuayAmaluza, 4 km E ofReptiles of Ecuador book database
EcuadorAzuayComunidad Puente GuayaquilReptiles of Ecuador book database
EcuadorAzuayVía Guarumales-MéndezArteaga et al. 2018
EcuadorMorona Santiago9 de OctubreTipantiza-Tuguminago et al. 2021
EcuadorMorona SantiagoChiguindaArteaga et al. 2018
EcuadorMorona SantiagoLaguna CormoránArteaga et al. 2018
EcuadorMorona SantiagoLaguna el EnmascaradoPhoto by Darwin Núñez
EcuadorMorona SantiagoLas TablasThis work; Fig. 1
EcuadorMorona SantiagoPlan Milagro, 8.8 km WSW ofKU 202950; VertNet
EcuadorMorona SantiagoPuchimiTorres-Carvajal et al. 2019
EcuadorMorona SantiagoRío CugushaArteaga et al. 2018
EcuadorMorona SantiagoSan José, 4 km E ofHarvey & Embert 2008
EcuadorMorona SantiagoSardinayacuArteaga et al. 2018
EcuadorPastazaLlanganatesPeters 1960
EcuadorPastazaLliguaReptiles of Ecuador book database
EcuadorPastazaRío PastazaHarvey & Embert 2008
EcuadorPastazaTzarentzaArteaga et al. 2018
EcuadorPastazaVía Puñapi–PatateReptiles of Ecuador book database
EcuadorTungurahuaAbitaguaArteaga et al. 2018
EcuadorTungurahuaAgoyánArteaga et al. 2018
EcuadorTungurahuaBañosArteaga et al. 2018
EcuadorTungurahuaBaños, Los SaucesReptiles of Ecuador book database
EcuadorTungurahuaCaserío MachayArteaga et al. 2018
EcuadorTungurahuaChamanapambaArteaga et al. 2018
EcuadorTungurahuaEl Topo*Boulenger 1912
EcuadorTungurahuaMapotoHarvey & Embert 2008
EcuadorTungurahuaPalmeraArteaga et al. 2018
EcuadorTungurahuaParque Juan Montalvo Arteaga et al. 2018
EcuadorTungurahuaReserva La CandelariaArteaga et al. 2018
EcuadorTungurahuaRío VerdeArteaga et al. 2018
EcuadorTungurahuaRío Verde, 3 km E ofArteaga et al. 2018
EcuadorTungurahuaUlbaArteaga et al. 2018
EcuadorTungurahuaVía RuntúnReptiles of Ecuador book database
EcuadorTungurahuaVizcayaArteaga et al. 2018
EcuadorTungurahuaYunguillaHarvey & Embert 2008
EcuadorZamora ChinchipeAlto MachinazaAlmendáriz et al 2014
EcuadorZamora ChinchipeConcesión ECSAArteaga et al. 2018
EcuadorZamora ChinchipeEl Limón, 5 km N ofPhoto by Darwin Núñez
EcuadorZamora ChinchipeEl RetornoArteaga et al. 2018
EcuadorZamora ChinchipeEstación Científica San FranciscoArteaga et al. 2018
EcuadorZamora ChinchipeGuayzimi AltoThis work; Fig. 1
EcuadorZamora ChinchipeReserva NumbamiArteaga et al. 2018
EcuadorZamora ChinchipeReserva Palmitera ValladolidReptiles of Ecuador book database
EcuadorZamora ChinchipeRomerillos AltoArteaga et al. 2018
EcuadorZamora ChinchipeZamora, 18.2 km W ofArteaga et al. 2018
EcuadorZamora ChinchipeZumbaArteaga et al. 2018
PeruCajamarcaEl ChaupeMena & Valdivia 2010
PeruCajamarcaHuamantangaArteaga et al. 2018
PeruCajamarcaJaénArteaga et al. 2018
PeruCajamarcaSanta Rosa de YungaKoch et al. 2018
PeruCajamarcaTabaconasArteaga et al. 2018