Published October 15, 2020. Updated May 25, 2026. Open access. | Purchase book ❯ |
Amazonian Toadhead (Bothrocophias hyoprora)
Reptiles of Ecuador | Serpentes | Viperidae | Bothrocophias hyoprora
English common names: Amazonian Toadhead, Amazonian Toad-headed Pitviper, Amazonian Hog-nosed Viper, Amazonian Hognose Viper.
Spanish common names: Nariz de puerco, hocico de puerco (Ecuador); sapa, equis sapa (Colombia); jergón pudridora, yatutu (Perú).
Recognition: ♂♂ 65.1 cmMaximum distance from the snout to the tip of the tail. ♀♀ 86 cmMaximum distance from the snout to the tip of the tail.. Botrocophias hyoprora can be identified from other Amazonian snakes by having a triangular-shaped head, heat-sensing pits between the eyes and nostrils, a stout body, non-prehensile tail, upturned snout, and tubercular keels on the dorsal scales.1,2 The dorsal color may be reddish brown, dark brown, reddish orange, yellowish, or gray, with 14–19 dark trapezoidal or rectangular dorsal blotches (Fig. 1).1,3 Bothrocophias hyoprora differs from B. microphthalmus by having a pattern of trapezoidal blotches rather than X-shaped markings and by having entire subcaudal scales.1,3 From Bothrops atrox and B. brazili, it differs by having an upturned snout.3
Figure 1: Individuals of Bothrocophias hyoprora from Amazonian Ecuador: Emerald Arch’s Reserve near Cuyabeno Reserve, Sucumbíos province (); Curaray medio, Pastaza province, Ecuador (); Macuma, Morona Santiago province, Ecuador (). j=juvenile.
Natural history: Bothrocophias hyoprora is a rarely seen cryptozoic snake of forested environments. The species occurs mainly in old-growth to moderately disturbed terra-firme and partially flooded evergreen lowland forests but may as well be found in forest borders and crops.1–3 Amazonian Toad-headed Pitvipers inhabit areas having an annual mean temperature of ~20–27° C and a mean precipitation of 1,659–4,227 mm.4 Amazonian Toadheads are most active during the first hours after sunset,1,2 waiting in ambush, moving on the forest floor, and occasionally crossing roads and trails.1,5 During the day, individuals often stay quiet, hidden from sun exposure in leaf-litter, under trunks, among roots, or at the base of trees.1,2,5 There are records of individuals perched on vegetation up to 5 m above the ground.6 Amazonian Toadheads are ambush predators. When prey is nearby, they “bite and release,” subsequently following the scent trail of the envenomed animal to eat it.1 Their diet consists primarily (41.5%) on lizards (including Alopoglossus atriventris and Potamites ecpleopus), but also on small mammals like rodents and marsupials (25%), frogs such as Allobates femoralis and Hyloxalus yasuni (25%), and centipedes (8.3%).1,7,8–11 They also occasionally include snakes in their diet.12 Individuals of B. hyoprora rely on camouflage as their primary defense mechanism.1 They are not aggressive, but calm and sluggish when confronted.3 When threatened, most individuals will try to flee or hide, while others will vigorously vibrate the tail against the substrate.1,7 The only recorded predator is the hawk Buteogallus schistaceus.1 Bothrocophias hyoprora is a venomous snake, but human envenomations caused by this species are infrequent, representing no more than 0.35–12.5% of the total number of snakebites at any given locality.13,14 Most reported envenomations have occurred in indigenous communities.15 The venom of B. hyoprora is necrotic, hemolytic, and cytotoxic.1,13,16 In humans, the venom causes intense pain, swelling, loss of consciousness, necrosis (death of tissues and cells), intense bleeding, and, in some cases, death.1,15 Females of B. hyoprora “give birth” (the eggs hatch within the mother) to 4–13 neonates that measure 14.8–19 cm in total length.1,2 One gravid female in Ecuador was found to contain 21 embryos.5 Under human care, one adult female lived for about eight years.1
Conservation: Least Concern Believed to be safe from extinction given current circumstances..17 Bothrocophias hyoprora is included in this category because the species is widely distributed throughout Amazonia over areas that retains the majority of their original forest cover. Approximately 89% of the species’ distribution in Ecuador overlaps with areas of pristine forest,18 including large protected areas such as Cuyabeno Wildlife Reserve and Yasuní National Park. Ongoing threats to the survival of some populations include forest destruction due to mining and the expansion of the agricultural frontier.
Distribution: Bothrocophias hyoprora is native to an area of approximately 513,480 km2 across the Amazon basin of Brazil, Bolivia, Colombia, Ecuador (Fig. 2), and Perú.19
Figure 2: Distribution of Bothrocophias hyoprora in Ecuador. See Appendix 1 for a complete list of the presence localities included in the map.
Etymology: The name Bothrocophias is derived from the Greek words bothros (=pit) and kophias (=snake), referring to the heat-sensing loreal pits.3 The specific epithet hyoprora is derived from the Greek words hyos (=hog) and prora (=snout), referring to the prominent upturned snout.3
Where to observe: Amazonian Toad-headed Pitvipers are located at a rate of about once every few months in forested areas throughout their distribution in Ecuador. Some of the best localities to find vipers of this species include the Yasuní Scientific Station, the Jatun Sacha Biological Reserve, and the Tiputini Biodiversity Station. These vipers are typically located by scanning the leaf-litter along trails in primary forest at night.
Special thanks to Maurice Fakkert for symbolically adopting the Amazonian Toadhead and helping bring the Reptiles of Ecuador book project to life.
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Authors: Andrés F. Aponte-Gutiérrez,aAffiliation: Grupo de Biodiversidad y Recursos Genéticos, Instituto de Genética, Universidad Nacional de Colombia, Bogotá, Colombia.,bAffiliation: Fundación Biodiversa Colombia, Bogotá, Colombia. Juan Acosta-Ortiz,cAffiliation: Universidad de los Llanos. Villavicencio, Colombia. and Leonardo Niño-CárdenasdAffiliation: Laboratorio de Anfibios, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia.
Editor: Alejandro ArteagaeAffiliation: Fundación Khamai, Reserva Arlequín, Ecoruta Paseo del Quinde km 56, Santa Rosa de Mindo, Pichincha 171202, Ecuador.
Photographer: Jose VieirafAffiliation: Tropical Herping (TH), Quito, Ecuador.,gAffiliation: ExSitu, Quito, Ecuador.
How to cite? Aponte-Gutiérrez A, Acosta-Ortiz J, Niño-Cárdenas L (2026) Amazonian Toadhead (Bothrocophias hyoprora). 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/RICT3003
Literature cited:
- Valencia JH, Garzón-Tello K, Barragán-Paladines ME (2016) Serpientes venenosas del Ecuador: sistemática, taxonomía, historial natural, conservación, envenenamiento y aspectos antropológicos. Fundación Herpetológica Gustavo Orcés, Quito, 653 pp.
- Cisneros-Heredia DF, Borja MO, Proaño D, Touzet JM (2006) Distribution and natural history of the Ecuadorian toad-headed pitvipers of the genus Bothrocophias. Herpetozoa 19: 17–26.
- Campbell JA, Lamar WW (2004) The venomous reptiles of the western hemisphere. Cornell University Press, Ithaca, 774 pp.
- Vaca-Guerrero JE (2012) Biogeografía del género Bothrocophias (Serpentes: Viperidae: Crotalinae), mediante modelamientos de nicho ecológico. BSc Thesis, Universidad Central del Ecuador, 116 pp.
- Field notes, Reptiles of Ecuador book project.
- Photographic record by Bryan Suson.
- Dixon JR, Soini P (1986) The reptiles of the upper Amazon Basin, Iquitos region, Peru. Milwaukee Public Museum, Milwaukee, 154 pp.
- Martins M, Marques OAV, Sazima I (2002) Ecological and phylogenetic correlates of feeding habits in Neotropical pitvipers of the genus Bothrops. In: Schuett GW, Höggren M, Douglas ME, Greene HW (Eds) Biology of the vipers. Eagle Mountain Publishing, Eagle Mountain, 307–328.
- Niceforo M (1938) Las serpientes colombianas de hocico proboscidiforme, grupo Bothrops lansbergii-nasuta-hyoprora. Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 2: 417–421.
- Santos JC, Cannatella DC (2011) Phenotypic integration emerges from aposematism and scale in poison frogs. Proceedings of the National Academy of Sciences of the United States of America 108: 6175-6180. DOI: 10.1073/pnas.1010952108
- Bernarde PS, Ferreira-Martins LS, Rodríguez-Oliveira J (2008) Bothrocophias hyoprora. Diet. Herpetological Review 39: 353.
- De Carvalho DT, de Fraga R, Eler ES, Kawashita-Ribeiro RA, Feldberg E, Vogt RC, De Carvalho MA, De Noronha JDC, Condrati LH, Bittencourt S (2013) Toad-headed pitviper Bothrocophias hyoprora (Amaral, 1935) (Serpentes, Viperidae): new records of geographic range in Brazil, hemipenial morphology, and chromosomal characterization. Herpetological Review 44: 410–414.
- Silva Haad J (1989) Las serpientes del genero Bothrops en la amazonia colombiana: aspectos biomedicos (epidemiologia, clinica y biologia del ofidismo). Acta Médica Colombiana 14: 148–165.
- Touzet JM (1986) Mordeduras de ofidios venenosos en la comunidad de los indígenas Siona-Secoya de San Pablo de Kantesyia y datos sobre la fauna de reptiles y anfibios locales. Publicaciones del Museo Ecuadoriano de Ciencias Naturales 7: 163–190.
- Warrell DA (2004) Snakebites in Central and South America: epidemiology, clinical features, and clinical management. In: Campbell JA, Lamar WW (Eds) The Venomous reptiles of the Western Hemisphere. Cornell University Press, Ithaca, 709–761.
- Bonilla C, Zavaleta A (1997) Estudio bioquímico del veneno de la serpiente Bothrops hyoprorus. Revista de Medicina Experimental 14: 18–32.
- Catenazzi A, Gonzales L, Nogueira CC, Hoogmoed MS, Cisneros-Heredia DF (2021) Bothrocophias hyoprora. The IUCN Red List of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2021-3.RLTS.T15204024A15204030.en
- MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
- 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
Appendix 1: Locality data used to create the distribution map of Bothrocophias hyoprora in Ecuador (Fig. 2).
| Country | Province | Locality | Source |
| Colombia | Caquetá | Bocana Canelos | Vaca Guerrero 2012 |
| Colombia | Caquetá | Los Ángeles | Sinchi Institute 2017 |
| Colombia | Caquetá | Solano | Campbell & Lamar 2004 |
| Colombia | Cauca | Churumbelos | MHNUC |
| Colombia | Cauca | Santa Rosa | Nogueira et al. 2019 |
| Colombia | Putumayo | Near Río Patascoy | iNaturalist; photo examined |
| Colombia | Putumayo | Río Juanambu | Campbell & Lamar 2004 |
| Colombia | Putumayo | RN La Isla Escondida | RN La Isla Escondida |
| Colombia | Putumayo | Vereda Cocaya | iNaturalist; photo examined |
| Colombia | Putumayo | Vereda Las Vegas | Vaca Guerrero 2012 |
| Colombia | Putumayo | Vereda Peneya | Photo by Brayan Coral Jaramillo |
| Ecuador | Morona Santiago | 10 de Agosto | Valencia et al. 2016 |
| Ecuador | Morona Santiago | 24 de Mayo | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Amazonas | Cisneros-Heredia et al. 2006 |
| Ecuador | Morona Santiago | Andush, 4 km NE of | Cisneros-Heredia et al. 2006 |
| Ecuador | Morona Santiago | Centro Shuar Kenkuim | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Centro Shuar Kiim | Cisneros-Heredia et al. 2006 |
| Ecuador | Morona Santiago | Chuwints | Cisneros-Heredia et al. 2006 |
| Ecuador | Morona Santiago | Cusuime | Nogueira et al. 2019 |
| Ecuador | Morona Santiago | El Tiink | Photo by Germán Petsain |
| Ecuador | Morona Santiago | Huamboya, Chiguaza | USNM 165315; VertNet |
| Ecuador | Morona Santiago | Macuma | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Mutintz | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Paantim | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Quebrada Yuwints | Nogueira et al. 2019 |
| Ecuador | Morona Santiago | Río Palora at 800 m | Photo by Jorge Brito |
| Ecuador | Morona Santiago | San Pedro | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Sapapentza | Campbell & Lamar 2004 |
| Ecuador | Morona Santiago | Taisha | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Timias | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Tiwintza | Vaca Guerrero 2012 |
| Ecuador | Morona Santiago | Tunants | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Wisui | Valencia et al. 2016 |
| Ecuador | Morona Santiago | Yawints | Valencia et al. 2016 |
| Ecuador | Napo | Chontapunta, 10 km SW of | iNaturalist; photo examined |
| Ecuador | Napo | Chontapunta, 13 km SW of | iNaturalist; photo examined |
| Ecuador | Napo | Gareno Lodge | Reptiles of Ecuador book database |
| Ecuador | Napo | Jatun Sacha | Valencia et al. 2016 |
| Ecuador | Napo | Near Huamaní | Valencia et al. 2016 |
| Ecuador | Napo | Pangayacu | Valencia et al. 2016 |
| Ecuador | Napo | Puerto Napo | UIMNH 55926; VertNet |
| Ecuador | Napo | Río Suno | Valencia et al. 2016 |
| Ecuador | Napo | Yachana Reserve | Vaca Guerrero 2012 |
| Ecuador | Napo | Yuralpa | Valencia et al. 2016 |
| Ecuador | Orellana | Chiruisla | Valencia et al. 2016 |
| Ecuador | Orellana | Dicaro | Valencia et al. 2016 |
| Ecuador | Orellana | El Edén | Valencia et al. 2016 |
| Ecuador | Orellana | Guiyero | Valencia et al. 2016 |
| Ecuador | Orellana | Joya de los Sachas | Campbell & Lamar 2004 |
| Ecuador | Orellana | Loreto | USNM 165313; VertNet |
| Ecuador | Orellana | N of Yasuní Scientific Station | iNaturalist; photo examined |
| Ecuador | Orellana | Nenkepare | Reptiles of Ecuador book database |
| Ecuador | Orellana | Pompeya Sur–NPF | Valencia et al. 2016 |
| Ecuador | Orellana | Pozo Capirón | Valencia et al. 2016 |
| Ecuador | Orellana | Pozo NPF | Paulina Romero, pers. comm. |
| Ecuador | Orellana | San José de Payamino | Photo by Ross Maynard |
| Ecuador | Orellana | San José de Suno | USNM 165311; VertNet |
| Ecuador | Orellana | Shiripuno Lodge | Photo by Bryan Suson |
| Ecuador | Orellana | Sinchichicta | Valencia et al. 2016 |
| Ecuador | Orellana | Souther part of YNP | Campbell & Lamar 2004 |
| Ecuador | Orellana | Tiputini Biodiversity Station | Cisneros-Heredia 2006 |
| Ecuador | Orellana | Vía NPF–Tivacuno, km 8 1/2 | Valencia et al. 2016 |
| Ecuador | Orellana | Vía Pompeya Sur-Iro, km 38 | Valencia et al. 2016 |
| Ecuador | Orellana | Vía Pompeya Sur–Iro, km 28 | Cisneros-Heredia et al. 2006 |
| Ecuador | Orellana | Vía Pompeya Sur–Iro, km 99 | Valencia et al. 2016 |
| Ecuador | Orellana | Yasuní Scientific Station | Reptiles of Ecuador book database |
| Ecuador | Pastaza | Alto Curaray | Valencia et al. 2016 |
| Ecuador | Pastaza | Balsaura | Ortega-Andrade 2010 |
| Ecuador | Pastaza | Cabeceras del Bobonaza | Valencia et al. 2016 |
| Ecuador | Pastaza | Campo Oglán | Valencia et al. 2016 |
| Ecuador | Pastaza | Campo Villano A | Valencia et al. 2016 |
| Ecuador | Pastaza | Canelos | USNM 165306; VertNet |
| Ecuador | Pastaza | Conambo | USNM 165302; VertNet |
| Ecuador | Pastaza | Curaray Medio | This work; Fig. 1 |
| Ecuador | Pastaza | Headwaters of the Río Tigre | Campbell & Lamar 2004 |
| Ecuador | Pastaza | Iwia (Achuar) | Peñafiel 2013 |
| Ecuador | Pastaza | Juyuintza | Ortega-Andrade 2010 |
| Ecuador | Pastaza | Kurintza | Ortega-Andrade 2010 |
| Ecuador | Pastaza | Montalvo | Valencia et al. 2016 |
| Ecuador | Pastaza | Pindoyacu | Ortega-Andrade 2010 |
| Ecuador | Pastaza | Río Capahuari | Valencia et al. 2016 |
| Ecuador | Pastaza | Río Copataza | Valencia et al. 2016 |
| Ecuador | Pastaza | Río Corrientes | Valencia et al. 2016 |
| Ecuador | Pastaza | Río Oglán | Valencia et al. 2016 |
| Ecuador | Pastaza | Río Pindo | Valencia et al. 2016 |
| Ecuador | Pastaza | Río Shionayacu | Valencia et al. 2016 |
| Ecuador | Pastaza | Río Tigre | USNM 165318; VertNet |
| Ecuador | Pastaza | Río Villano | Valencia et al. 2016 |
| Ecuador | Pastaza | Santa Clara | Valencia et al. 2016 |
| Ecuador | Pastaza | Sarayacu | Valencia et al. 2016 |
| Ecuador | Pastaza | Sarayacu–Montalvo | Campbell & Lamar 2004 |
| Ecuador | Pastaza | Upstream Río Copataza | Campbell & Lamar 2004 |
| Ecuador | Pastaza | Uyuimi | NCI |
| Ecuador | Pastaza | Wayusentza | Campbell & Lamar 2004 |
| Ecuador | Sucumbíos | Along río San Miguel | Reptiles of Ecuador book database |
| Ecuador | Sucumbíos | Atenas | Vaca Guerrero 2012 |
| Ecuador | Sucumbíos | Between Cascales and Campo Bermejo | Vaca Guerrero 2012 |
| Ecuador | Sucumbíos | Campo Andes Petroleum | Vaca Guerrero 2012 |
| Ecuador | Sucumbíos | Campo Bermejo | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Dureno, north of | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Emerald Arch’s Reserve | This work; Fig. 1 |
| Ecuador | Sucumbíos | Lumbaqui | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Pañacocha | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Pitsorie-Setsacco | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Pozo petrolero Secoya 32 | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Pozo petrolero Shirley A | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Reserva Cofán-Dureno | iNaturalist; photo examined |
| Ecuador | Sucumbíos | Río Aguarico near Cuyabeno | Campbell & Lamar 2004 |
| Ecuador | Sucumbíos | Sacha Lodge | Photo by Bryan Suson |
| Ecuador | Sucumbíos | San Pablo de Kantesiya | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Santa Elena | Torres-Carvajal & Salazar-Valenzuela 2012 |
| Ecuador | Sucumbíos | Tarapoa | Valencia et al. 2016 |
| Ecuador | Sucumbíos | Zábalo | Photo by Juan Carlos Ríos |
| Ecuador | Sucumbíos | Zancudococha | Cisneros-Heredia et al. 2006 |
| Ecuador | Zamora Chinchipe | El Pangui | Valencia et al. 2016 |
| Ecuador | Zamora Chinchipe | Los Encuentros | Valencia et al. 2016 |
| Ecuador | Zamora Chinchipe | Maycu | Darwin Núñez, pers. comm. |
| Ecuador | Zamora Chinchipe | Namacuntza | Nogueira et al. 2019 |
| Ecuador | Zamora Chinchipe | Paquisha | Reptiles of Ecuador book database |
| Ecuador | Zamora Chinchipe | Polvorín | Valencia et al. 2016 |
| Ecuador | Zamora Chinchipe | Shaime | Cisneros-Heredia et al. 2006 |
| Ecuador | Zamora Chinchipe | Tundayme | Valencia et al. 2016 |
| Perú | Amazonas | Caterpiza | MVZ 175374; VertNet |
| Perú | Amazonas | Puerto Pakuy | Lomonte et al. 2020 |
| Perú | Amazonas | Quebrada Kampankis | FMNH 2012 |
| Perú | Loreto | Aguas Negras | FMNH 2008 |
| Perú | Loreto | Andoas, 70 km W of | Campbell & Lamar 2004 |
| Perú | Loreto | Charupa | Vaca Guerrero 2012 |
| Perú | Loreto | Güeppí | FMNH 2008 |
| Perú | Loreto | Lote 39 | Tomba 2019 |
| Perú | Loreto | Manseriche | Campbell & Lamar 2004 |
| Perú | Loreto | Morona | Vaca Guerrero 2012 |
| Perú | Loreto | Olaya–Tigre | Campbell & Lamar 2004 |
| Perú | Loreto | Pampa Hermosa | Campbell & Lamar 2004 |
| Perú | Loreto | Pavayacu, 32 km NW of | Vaca Guerrero 2012 |
| Perú | Loreto | Perenco Petroleum road near Arica | Campbell & Lamar 2004 |
| Perú | Loreto | Pongo Chinim | FMNH 2012 |
| Perú | Loreto | Pozo al este de Andoas | Vaca Guerrero 2012 |
| Perú | Loreto | Pozo al norte de Andoas | Vaca Guerrero 2012 |
| Perú | Loreto | Pozo al sur del Río Tigre | Vaca Guerrero 2012 |
| Perú | Loreto | Zona Reservada Güepi | iNaturalist; photo examined |
| Perú | Loreto | Zona Reservada Pucacuro 1 | Campbell & Lamar 2004 |
| Perú | Loreto | Zona Reservada Pucacuro 2 | Campbell & Lamar 2004 |