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DOI10.47051/ETXC3519 Published December 28, 2020. Updated May 2, 2024. Open access.

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Brown-banded Watersnake (Helicops angulatus)

Reptiles of Ecuador | Serpentes | Colubridae | Helicops angulatus

English common names: Brown-banded Watersnake, Broad-banded Water Snake, Mountain Keelback, South American Water Snake, Amazonian Water Snake, Water Mapepire.

Spanish common names: Culebra acuática angulada, culebra de agua angulada (Ecuador); cuatro nariz de agua, falsa cuatro narices, mapaná de agua (Colombia); falsa mapanare de agua, sapa, cascabel de agua (Venezuela); jergón de agua, serpiente de agua, yacu jergón (Perú).

Recognition: ♂♂ 68.6 cmMaximum distance from the snout to the tip of the tail. ♀♀ 73.5 cmMaximum distance from the snout to the tip of the tail..^1,2 Helicops angulatus can be distinguished from most Amazonian snakes by having the eyes and nostrils on top of the head.^3,4 The pupil is round to semi-elliptical,^4,5 and the dorsum is grayish brown to olive brown with 21 to 25 dark transverse bands with black edges (Fig. 1).^1,5,6 The first dorsal band extends anteriorly in the middle into a tent-shaped mark.^5,7 Some individuals may present metachrosis (color change), becoming lighter at night.⁸ Helicops angulatus can be distinguished from H. pastazae and H. hagmanni by having transverse dorsal crossbands.^4,9 Hydrops martii and ⁹ Hydrops triangularis differ from H. angulatus by having a greater number of black bands (39–76) on the body.^1,7 In addition, Hydrops triangularis may have red spots dorsally.¹

Figure 1: Individuals of Helicops angulatus from Ecuador: Cabeceras del Bobonaza, Pastaza province (); Jatun Sacha Biological Reserve, Napo province (); Yasuní Scientific Station, Orellana province (). j=juvenile.

Natural history: Helicops angulatus is a comparatively common semi-aquatic snake that inhabits lentic bodies of water with abundant aquatic vegetation.^1,10 It can also be found in streams, rivers, lakes, lagoons, fish ponds, and temporary ponds in open as well as forested areas with various degrees of human intervention.^1,5,11,12 Brown-banded Watersnakes are typically active between 6:00 and 10:00 pm,¹³ but can also be diurnal.⁵ They are aquatic and can be found at different depths. When in shallow waters, individuals usually have the body submerged and part of the head above the surface.⁵ They move short distances per day (an average of ~3.6 m/day),¹⁴ not only in water but also on mud and soil close to water bodies.¹⁰

Brown-banded Watersnakes are sit-and-wait foragers.¹⁵ Their diet includes mostly fish, but also amphibians in adult stage as well as on their eggs and tadpoles.^5,11,16–18 Amphibian prey include Boana boans,¹⁷ B. geographica, Osteocephalus taurinus,⁵ Scinax ruber,¹⁷ Adenomera hylaedactyla,¹⁹ Allobates femoralis,²⁰ Rhinella margaritifera,²¹ and R. marina.^17,22 Helicops angulatus also feeds on lizards (such as Alopoglossus spp., and Potamites ecpleopus),^1,18 carrion,²³ and invertebrates (including giant earthworms of the family Glossoscolecidae),²⁴ although some of the latter may be consumed by secondary ingestion.²¹ Also, there are records of plastic being ingested by members of this species.²⁵ Brown-banded Watersnakes are preyed upon by snakes (including Eunectes murinus,²⁶ Drepanoides anomalus,²⁷ Clelia clelia,²⁸ and Drymarchon corais²⁹), herons (Tigrisoma lineatum),³⁰ and aquatic larvae of the lion ant (Corydalidae).³¹

The behavior of Helicops angulatus varies among individuals, so it is possible to find docile or defensive snakes.⁵ However, the typical defense consists of making an S-coil, flattening the body and head dorsoventrally, and striking.^4,5,13 When manipulated, individuals rotate the body, bite, and produce cloacal discharges.^5,13,16 They may also poke with the tip of the tail.¹³ Helicops angulatus is an opisthoglyphous snake, meaning it has enlarged teeth towards the rear of the maxilla, and is considered mildly venomous (LD50The median lethal dose (LD50) is a measure of venom strength. It is the minium dosage of venom that will lead to the deaths of 50% of the tested population. 5.3 mg/kg in mice).³² The venom of this species has proteolytic (causing protein breakdown) and neurotoxic (acting on the nervous system) components. Humans who have been bitten present local pain as well as changes in coagulation time.^32,33 Accidents involving the Brown-banded Watersnakes are frequent in children and adults in some rural areas.^33,34

Helicops angulatus can lay eggs as well as give birth to live young.³⁵ However, there are no records of the occurrence of both reproductive modes in the same population.^35,36 Clutch/litter sizes range between 1–24 with incubation times of ~18 to 45 days.^5,8,35,37 Under human care, one female lived for seven years.⁸

Conservation: Least Concern Believed to be safe from extinction given current circumstances..³⁸ Helicops angulatus is listed in this category given its wide distribution, high population densities, and tolerance for human-modified environments.³⁸ However, the species’ presence near urbanized areas makes individuals especially susceptible to being killed by people out of concern or because it can be confused with the venomous snake Bothrops atrox.^3,5,16 Other causes of mortality include death from vehicular traffic and ingestion of plastic.^15,25

Distribution: Helicops angulatus is widely distributed throughout the Amazon in Bolivia, Brazil, Colombia, Ecuador (Fig. 2), French Guiana, Guyana, Peru, Suriname and Venezuela. It also occurs in Trinidad Island, as well as in the Cerrado, Caatinga, and Atlantic Forest biomes in Brazil.³⁹

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

Etymology: The generic name Helicops, which comes from the Greek words helix (=turned) and ops (=eye),⁴⁰ refers to the direction of the eyes in this group of snakes, oriented not directly outwards, but obliquely upwards.^41,42 The specific epithet angulatus, which comes from the Latin angulus (=angle) and the prefix -atus (=provided with),⁴⁰ refers to the presence of prominent keels on the dorsal scales that give the appearance of many angles.⁴²

See it in the wild: Brown-banded Watersnakes can be located at a rate of about once every few days in forested areas throughout the species’ area of distribution in Ecuador, especially along slow-moving whitewater rivers. Some of the best locations to find Helicops angulatus in the wild in Ecuador are Yasuní National Park, Yarina Lodge, and Jatun Sacha Biological Reserve.

Authors: Juan Acosta-Ortiz,^aAffiliation: Universidad de los Llanos. Villavicencio, Colombia. Andrés F. Aponte-Gutiérrez,^bAffiliation: Grupo de Biodiversidad y Recursos Genéticos, Instituto de Genética, Universidad Nacional de Colombia, Bogotá, Colombia.^,cAffiliation: Fundación Biodiversa Colombia, Bogotá, Colombia. and Leonardo Niño-Cárdenas^dAffiliation: Laboratorio de Anfibios, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia.

Editor: Alejandro Arteaga^eAffiliation: Tropical Herping (TH), Quito, Ecuador.

Photographers: Jose Vieira^eAffiliation: Tropical Herping (TH), Quito, Ecuador.^,fAffiliation: ExSitu, Quito, Ecuador. and and Sebastián Di Doménico^gAffiliation: Keeping Nature, Bogotá, Colombia.

How to cite? Acosta-Ortiz J, Aponte-Gutiérrez A, Niño-Cárdenas L (2024) Brown-banded Watersnake (Helicops angulatus). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: www.reptilesofecuador.com. DOI: 10.47051/ETXC3519

Literature cited:

1. Dixon JR, Soini P (1986) The reptiles of the upper Amazon Basin, Iquitos region, Peru. Milwaukee Public Museum, Milwaukee, 154 pp.
2. Gasc JP, Rodrigues MT (1980) Liste préliminaire des serpents de Guyane Française. Bulletin du Muséum National d’Histoire Naturelle 2: 559–598.
3. Cunha OR, Nascimento FP (1993) Ofídios da Amazônia. As cobras da região leste do Pará. Papéis Avulsos Museu Paraense Emílio Goeldi 40: 9–87.
4. de Fraga R, Lima AP, da Costa Prudente AL, Magnusson WE (2013) Guia de cobras da região de Manaus - Amazônia Central. Editopa Inpa, Manaus, 303 pp.
5. Martins M, Oliveira ME (1998) Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetological Natural History 6: 78–150.
6. Duellman WE (2005) Cusco amazónico: the lives of amphibians and reptiles in an Amazonian rainforest. Cornell University Press, Ithaca, 433 pp.
7. Roze JA (1966) La taxonomía y zoogeografía de los ofidios en Venezuela. Universidad central de Venezuela, Caracas, 362 pp.
8. Natera-Mumaw M, Esqueda-González LF, Castelaín-Fernández M (2015) Atlas serpientes de Venezuela. Dimacofi Negocios Avanzados S.A., Santiago de Chile, 456 pp.
9. Pérez-Santos C, Moreno AG (1988) Ofidios de Colombia. Museo Regionale di Scienze Naturali, Torino, 517 pp.
10. Field notes, Reptiles of Ecuador book project.
11. Ford NB, Ford DF (2002) Notes on the ecology of the South American Water Snake Helicops angulatus (Squamata: Colubridae) in Nariva Swamp, Trinidad. Caribbean Journal of Science 38: 129–132.
12. Acosta-Ortiz JM, Pardo-Moreno YA (2019) La rana vaquera Physalaemus fischeri (Anura: Leptodactylidae) como nuevo registro en la dieta de la serpiente acuática Helicops angulatus (Serpentes: Colubridae). Boletín de la Asociación Herpetológica Española 30: 10–12.
13. Field notes of Juan Manuel Acosta-Ortiz.
14. Henderson RW, Nickerson MA, Ketcham S (1976) Short term movements of the snakes Chironius carinatus, Helicops angulatus and Bothrops atrox in Amazonian Peru. Herpetologica 32: 304–310.
15. Rincón-Aranguri M, Urbina-Cardona N, Galeano S, Bock BC, Páez VP (2019) Road kill of snakes on a highway in an Orinoco ecosystem: landscape factors and species traits related to their mortality. Tropical Conservation Science 12: 1–18. DOI: 10.1177/1940082919830832
16. Marques R, Mebert K, Fonseca E, Rödder D, Solé M, Tinôco MS (2016) Composition and natural history notes of the coastal snake assemblage from Northern Bahia, Brazil. ZooKeys 611: 93–142. DOI: 10.3897/zookeys.611.9529
17. de Carvalho Teixeira C, de Assis Montag LF, dos Santos-Costa MC (2017) Diet composition and foraging habitat use by three species of water snakes, Helicops Wagler, 1830, (Serpentes: Dipsadidae) in Eastern Brazilian Amazonia. Journal of Herpetology 51: 215–222. DOI: 10.1670/15-161
18. Scartozzoni R (2009) Estratégias reprodutivas e ecologia alimentar de serpentes aquáticas da tribo Hydropsini (Dipsadidae, Xenodontinae). PhD thesis, Universidad de São Paulo, 160 pp.
19. Tavares-Pinheiro R, Pedroso-Santos F, Sanches PR, Figueiredo AMB, Costa-Campos CE (2019) Helicops angulatus (Amazonian Water Snake). Diet. Herpetological Review 50: 157.
20. Costa-Campos CE, Esteves PH, Santos LE, Sousa JC (2017) Predation on the brilliant-thighed poison frog Allobates femoralis (Aromobatidae) by the Amazonian water snake Helicops angulatus (Dipsadidae). Herpetology Notes 10: 665–667.
21. Reis JA, Reis EJ, Cunha L, Rocha AM (2010) Helicops angulatus (Water Snake). Diet and reproduction. Herpetological Review 41: 93.
22. Kaefer IL, Montanarin A (2003) Helicops angulatus (South American Watersnake). Diet. Herpetological Review 42: 291.
23. Méndes-Junior RNG, Vasconcelos HCG, Sanches Gonçalves T, De Fraga R (2013) Helicops angulatus (Brown-banded Watersnake). Diet/scavenging. Herpetological Review 44: 330.
24. Strüssmann C, de Brito ES, Marques OAV (2013) What do water snakes eat? First report of predation by a neotropical hydropsini snake on giant earthworms (Glossoscolecidae). Salamandra 49: 48–50.
25. França RC, Sampaio ILR, França FGR (2018) Helicops angulatus (Brown-banded Watersnake). Plastic ingestion. Herpetological Review 49: 342–343.
26. Infante-rivero E, Natera-mumaw M, Marcano A (2010) Extension of the distribution of Eunectes murinus (Linnaeus, 1758) and Helicops angulatus (Linnaeus, 1758) in Venezuela, with notes on ophiophagia. Herpetotropicos 4: 39.
27. Crnobrna B, Armes M, Fonseca H (2016) Drepanoides anomalus (Amazon Egg-eating Snake). Diet/ophiophagy. Herpetological Review 47: 478.
28. Photo by Vincent Vos.
29. Photo by Dick Lock.
30. Koski DA, Mônico AT, Valadares AP (2016) Helicops angulatus (Watersnake). Predation. Herpetological Review 47: 478–479.
31. Muniz S, Albuquerque B (2012) Helicops angulatus (Watersnake). Predation. Herpetological Review 43: 493.
32. Estrella A, Rodríguez-Torres A, Serna L, Navarrete LF, Rodríguez-Costa A (2012) Is the South American water snake Helicops angulatus (Linnaeus, 1758) (Dipsadidae: Xenodontinae) venomous? Herpetotropicos 5: 79–84.
33. da Silva AM, Mendes VKG, Monteiro WM, Bernarde PS (2019) Non-venomous snakebites in the western Brazilian Amazon. Revista da Sociedade Brasileira de Medicina Tropical 52: 2–5. DOI: 10.1590/0037-8682-0120-2019
34. Moreno E, Queiroz-Andrade M, Lira-Da-Silva RM, Tavares-Neto J (2005) Clinical and epidemiological characteristics of snakebites in Rio Branco, Acre. Revista da Sociedade Brasileira de Medicina Tropical 38: 15–21. DOI: 10.1590/s0037-86822005000100004
35. Braz H, Scartozzoni R, Almeida-Santos SM (2016) Reproductive modes of the South American water snakes : a study system for the evolution of viviparity in squamate reptiles. Zoologischer Anzeiger 263: 33–44. DOI: 10.1016/j.jcz.2016.04.003
36. Rossman DA (1984) Helicops angulatus (South American water snake). Reproduction. Herpetological Review 15: 50.
37. Rossman DA (1974) Miscellaneous notes on the South American water snake genus Helicops. HISS News-Journal 1: 189–192.
38. Nogueira C, Gonzales L, Cisneros-Heredia DF, Gagliardi G, Catenazzi A, Schargel W, Rivas G, Murphy J (2019) Helicops angulatus. The IUCN Red List of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2019-3.RLTS.T15178420A15178466.en
39. Nogueira CC, Argôlo AJS, Arzamendia V, Azevedo JA, Barbo FE, Bérnils RS, Bolochio BE, Borges-Martins M, Brasil-Godinho M, Braz H, Buononato MA, Cisneros-Heredia DF, Colli GR, Costa HC, Franco FL, Giraudo A, Gonzalez RC, Guedes T, Hoogmoed MS, Marques OAV, Montingelli GG, Passos P, Prudente ALC, Rivas GA, Sanchez PM, Serrano FC, Silva NJ, Strüssmann C, Vieira-Alencar JPS, Zaher H, Sawaya RJ, Martins M (2019) Atlas of Brazilian snakes: verified point-locality maps to mitigate the Wallacean shortfall in a megadiverse snake fauna. South American Journal of Herpetology 14: 1–274. DOI: 10.2994/SAJH-D-19-00120.1
40. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.
41. Wagler JG (1830) Natürliches System der Amphibien: mit vorangehender Classification der Säugetiere und Vögel: ein Beitrag zur vergleichenden Zoologie. J.G. Cotta'scchen, München, 354 pp. DOI: 10.5962/bhl.title.58730
42. Duméril AMC, Bibron G, Duméril AHA (1854) Erpétologie générale ou Histoire Naturelle complète des Reptiles. Librairie Encyclopédique de Roret, Paris, 780 pp. DOI: 10.5962/bhl.title.45973

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

Country	Province	Locality	Source
Colombia	Caquetá	Belén de Los Andaquíes	SINCHI 942
Colombia	Caquetá	Florencia	MLS 750
Colombia	Caquetá	La Montañita	ICN 10737
Colombia	Caquetá	Tres Esquinas	MLS 754
Colombia	Putumayo	El Salado	PUJ 82
Colombia	Putumayo	La Hormiga	PUJ 262
Colombia	Putumayo	Orito	iNaturalist
Colombia	Putumayo	Puerto Leguizamo	Nogueira et al. 2019
Colombia	Putumayo	Tres esquinas	Nogueira et al. 2019
Ecuador	Morona Santiago	Comunidad Shuar Amaru	Online multimedia
Ecuador	Morona Santiago	Cusuime	Ortega-Andrade 2010
Ecuador	Morona Santiago	Macuma	Cisneros-Heredia 2006
Ecuador	Morona Santiago	Marantian Wildlife Refuge	Photo by Alex Achig
Ecuador	Morona Santiago	Río Cusuime	Nogueira et al. 2019
Ecuador	Napo	Archidona	Nogueira et al. 2019
Ecuador	Napo	Centro de Rescate AmaZOOnico	iNaturalist
Ecuador	Napo	Chontapunta	iNaturalist
Ecuador	Napo	Finca Fischer	TCWC 67312
Ecuador	Napo	Grand Selva Lodge	Photo by William Freedberg
Ecuador	Napo	Jatun Sacha Reserve	This work
Ecuador	Napo	Liana Lodge	iNaturalist
Ecuador	Napo	Puerto Napo	Nogueira et al. 2019
Ecuador	Napo	Río Pano	iNaturalist
Ecuador	Napo	Río Pucuno	USNM 204141
Ecuador	Napo	Río Tena	iNaturalist
Ecuador	Napo	Sani Lodge dock	iNaturalist
Ecuador	Napo	Tangara Huasi	iNaturalist
Ecuador	Napo	Tena	iNaturalist
Ecuador	Napo	Tena, Isidro Ayora	iNaturalist
Ecuador	Napo	Yachana Reserve	This work
Ecuador	Napo	Zatzayacu	Photo by Ricardo Íñiguez
Ecuador	Orellana	Concepción	USNM 204145
Ecuador	Orellana	Cononaco	This work
Ecuador	Orellana	El Coca	MCZ 163952
Ecuador	Orellana	El Coca, 5 km N of	Nogueira et al. 2019
Ecuador	Orellana	El Descanso	Nogueira et al. 2019
Ecuador	Orellana	Joya de los Sachas	Nogueira et al. 2019
Ecuador	Orellana	Loreto	USNM 204143
Ecuador	Orellana	Nuevo Rocafuerte	Nogueira et al. 2019
Ecuador	Orellana	NWC Parrot clay lick	iNaturalist
Ecuador	Orellana	Pindo	Photo by Ernesto Arbeláez
Ecuador	Orellana	Pozo Amo	Nogueira et al. 2019
Ecuador	Orellana	Pozo Ishpingo	Nogueira et al. 2019
Ecuador	Orellana	Pozo Nashiño	Nogueira et al. 2019
Ecuador	Orellana	Río Coca	Nogueira et al. 2019
Ecuador	Orellana	Río Cotapino	Nogueira et al. 2019
Ecuador	Orellana	San José de Payamino	Maynard et al. 2016
Ecuador	Orellana	Tambococha	Nogueira et al. 2019
Ecuador	Orellana	Tiputini Biodiversity Station	iNaturalist
Ecuador	Orellana	Via Pompeya–Iro, km 10	Nogueira et al. 2019
Ecuador	Orellana	Vía Pompeya–Iro, km 72	Nogueira et al. 2019
Ecuador	Orellana	Yasuní Scientific Station	Nogueira et al. 2019
Ecuador	Pastaza	Arutam	SMF 90947
Ecuador	Pastaza	Balsaura	Ortega-Andrade 2010
Ecuador	Pastaza	Bobonaza	Nogueira et al. 2019
Ecuador	Pastaza	Bobonaza, 5.7 km SE of	Nogueira et al. 2019
Ecuador	Pastaza	Cabeceras del Río Bobonaza	This work
Ecuador	Pastaza	Canelos	Nogueira et al. 2019
Ecuador	Pastaza	Conambo	Ortega-Andrade 2010
Ecuador	Pastaza	Curaray Medio	This work
Ecuador	Pastaza	Heimatlos Lodge	Photo by Ferhat Gundogdu
Ecuador	Pastaza	Indillana	iNaturalist
Ecuador	Pastaza	Kapawi Reserve	iNaturalist
Ecuador	Pastaza	Kurintza	Nogueira et al. 2019
Ecuador	Pastaza	Madre Tierra	Nogueira et al. 2019
Ecuador	Pastaza	Montalvo	Nogueira et al. 2019
Ecuador	Pastaza	Pindoyacu	Ortega-Andrade 2010
Ecuador	Pastaza	Puente Renacer Amazonico	iNaturalist
Ecuador	Pastaza	Puyo	Photo by Danilo Medina
Ecuador	Pastaza	Río Curaray	iNaturalist
Ecuador	Pastaza	Río Tigre	USNM 204139
Ecuador	Pastaza	Sacha Yaku Reserve	This work
Ecuador	Pastaza	Sarayacu	USNM 204135
Ecuador	Pastaza	Tamandúa Reserve	Photo by Jorge Flores
Ecuador	Sucumbíos	Gonzalo Pizarro	iNaturalist
Ecuador	Sucumbíos	Lago Agrio	Nogueira et al. 2019
Ecuador	Sucumbíos	Nicky Amazon Lodge	iNaturalist
Ecuador	Sucumbíos	Pañacocha, 2.5 km S of	Nogueira et al. 2019
Ecuador	Sucumbíos	Puerto Libre	Duellman, 1978
Ecuador	Sucumbíos	Putumayo	iNaturalist
Ecuador	Sucumbíos	Sacha Lodge	Photo by Charlie Vogt
Ecuador	Sucumbíos	Santa Cecilia	Duellman, 1978
Ecuador	Sucumbíos	Santa Elena	iNaturalist
Perú	Amazonas	Nazareth	MVZ 163275
Perú	Amazonas	Puerto Galilea	USNM 566570
Perú	Amazonas	Río Santiago	USNM 566574
Perú	Loreto	Andoas	Nogueira et al. 2019

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