Published February 7, 2024. Open access.

Gallery ❯

Red-tailed Boa (Boa constrictor)

Reptiles of Ecuador | Serpentes | Boidae | Boa constrictor

English common names: Red-tailed Boa, Common Boa.

Spanish common names: Matacaballo amazónica (Ecuador); tragavenado (Venezuela); guio (Colombia).

Recognition: ♂♂ 170 cmMaximum distance from the snout to the tip of the tail. ♀♀ 445 cmMaximum distance from the snout to the tip of the tail..1,2 The Red-tailed Boa (Boa constrictor) can be identified from other boas by having small scales on the snout, a vertically elliptical pupil, no heat-sensitive pits on the lips, and presence of pelvic spurs.3,4 The background dorsal coloration is light brown with a series of dark brown markings forming a chain pattern.5 These are red and black on the tail (Fig. 1).35 The head has three dark stripes from the snout to the nape, a dorsal one extending to the neck and one on each side of the head.4,5 This species differs from B. imperator by having a reddish tail.3,4

Figure showing variation among individuals of Boa constrictor

Figure 1: Individuals of Boa constrictor: unknown locality, Ecuador (); Yasuní National Park, Orellana province, Ecuador (); Hato La Aurora, Casanare department, Colombia (); unknown locality, Venezuela (). j=juvenile.

Natural history: Boa constrictor is a heavy bodied primarily terrestrial snake, with juveniles being more arboreal than adults.3,4,6 This boa has nocturnal habits and forages primarily on the rainforest floor, but may also utilize arboreal perches up to 13 m above the ground7 as well pillars in buildings.38 During the day, Red-tailed Boas usually remain coiled at ground level, on trees, or in tree holes,6 but may also be seen feeding9 or crossing roads.6,7 They utilize both active foraging and ambush strategies to capture prey. Seized prey is wrapped by body coils and constricted until suffocation.4 Prey items include lizards (such as Iguana iguana10 and Ameiva ameiva11), birds, and mammals such as rodents, armadillos, marsupials, bats, and small primates.6,12,13 Domestic animals such as dogs, cats, and rabbits are frequently consumed.10,14 When threatened, these boas make an S-coil and may produce a long, loud hiss.6 There are recoded instances of predation on members of this species by snakes (Eunectes murinus15 and Clelia clelia16). The breeding season in B. constrictor coincides with the local dry season,4 with as many as 10 males being found tangled around a single female.17 During courtship, the males use the pelvic spurs, which are usually larger than those of females’.18 After a gestation period of 5–8 months, females “give birth” (the eggs hatch within the mother) to 10–64 young.8 In captivity, individuals can live up to 40 years.4

Reader support helps us keep the Reptiles of Ecuador book 100% free.

Conservation: Least Concern Believed to be safe from extinction given current circumstances..19 Boa constrictor is listed in this category because the species has large, stable populations and a wide distribution that includes numerous protected areas.19 However, anecdotal informations suggest that some populations are declining. Throughout the Amazon, wild boas are marketed as pets and captured for their skin and meat. It is estimated that several hundred live individuals and raw skins are shipped annually from Iquitos, Peru to pet dealers and tanneries around the world.20

Distribution: Boa constrictor is widely distributed throughout northern South America, occurring in Argentina, Bolivia, Brazil, Ecuador (Fig. 2), French Guiana, Guyana, Paraguay, Peru, Suriname, Trinidad and Tobago, and Venezuela.

Distribution of Boa constrictor in Ecuador

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

Etymology: The generic name Boa is a Latin word meaning “oxen-killer.”21 The specific epithet constrictor comes from the Latin word constricto (=to tighten strongly),22 and refers to the fact that this species kills by constriction.

See it in the wild: Red-tailed Boas are the most common pet snake in Ecuador, but they are rarely seen in the wild. The localities having the greatest number of recent observations are Limoncocha Biological Reserve and Yasuní National Park.

Special thanks to Ian Gillespie for symbolically adopting the Red-tailed Boa and helping bring the Reptiles of Ecuador book project to life.

Click here to adopt a species.

Authors: Danna Duque-Torres,aAffiliation: Grupo de Ornitología, Universidad Nacional de Colombia, Bogotá, Colombia. Andrés F. Aponte-Gutiérrez,bAffiliation: Grupo de Investigación en Ciencias de la Orinoquía, Universidad Nacional de Colombia sede Orinoquía, Arauca, Colombia.,cAffiliation: Fundación Biodiversa Colombia, Bogotá, Colombia. and Tatiana Molina-MorenodAffiliation: Departamento de Biología, Universidad de los Llanos, Villavicencio, Colombia.

Editor: Alejandro ArteagaeAffiliation: Tropical Herping (TH), Quito, Ecuador.

Photographer: Jose VieirafAffiliation: Tropical Herping (TH), Quito, Ecuador.,gAffiliation: ExSitu, Quito, Ecuador.

How to cite? Duque-Torres D, Aponte-Gutiérrez A, Molina-Moreno T (2024) Red-tailed Boa (Boa constrictor). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/HTXZ2458

Literature cited:

  1. Gadd JP (1983) Observations on the sexual behavior of the Boa constrictor constrictor in captivity, with notes on an unsuccessful parturition. British Herpetological Society Bulletin 6: 39–41.
  2. Watkins-Colwell GJ, Leenders TAAM (2003) Boa constrictor (Boa Constrictor): maximum body size. Herpetological Review 34: 61.
  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. O’Shea M (2007) Boas and pythons of the world. New Holland Publishers, London, 160 pp.
  5. 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.
  6. Martins M, Oliveira ME (1998) Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetological Natural History 6: 78–150.
  7. Field notes, Reptiles of Ecuador book project.
  8. Duellman WE (2005) Cusco amazónico: the lives of amphibians and reptiles in an Amazonian rainforest. Cornell University Press, Ithaca, 433 pp.
  9. Acosta-Ortiz J, Bobadilla-Molina J, González A, Martínez-Vélez S (2021) Nuevos registros de depredación por Boa constrictor (Serpentes: Boidae) en Colombia. Revista Latinoamericana de Herpetología 4: 164–166. DOI: 10.22201/fc.25942158e.2021.1.214
  10. Natera-Mumaw M, Esqueda-González LF, Castelaín-Fernández M (2015) Atlas serpientes de Venezuela. Dimacofi Negocios Avanzados S.A., Santiago de Chile, 456 pp.
  11. Beebe W (1945) Field notes on the lizards of Kartabo, British Guiana, and Caripito, Venezuela. Part 3. Teiidae, Amphisbaenida, and Scincidae. Zoologica 30: 7–32.
  12. dos Santos-Costa MC, Maschio GF, da Costa Prudente AL (2015) Natural history of snakes from Floresta Nacional de Caxiuanã, eastern Amazonia, Brazil. Herpetology Notes 8: 69–98.
  13. de O Cabral S, de S Freitas I, Morlanes V, Katzenberger M, Calabuig C (2018) Seed dispersers: a new facet of the ecological role of Boa constrictor constrictor Linnaeus 1758. Biota Neotropica 19: e20180626. DOI: 10.1590/1676-0611-BN-2018-0626
  14. Murphy JC (1997) Amphibians and reptiles of Trinidad and Tobago. Krieger, Malabar, 245 pp.
  15. Thomas O, Allain SJR (2021) A review of prey taken by anacondas (Squamata: Boidae: Eunectes). Reptiles & Amphibians 28: 329–334.
  16. Photo by Josua Hannink.
  17. Boos H (2001) The snakes of Trinidad and Tobago. Texas A&M University Press, College Station, 270 pp.
  18. Anzai RK, Fontana Eleuterio N, De Oliveira Lima T, Haddad Manfio R, De Almeida Santos SM (2023) Pelvic spur use during courtship and mating in the Red-tailed Boa Boa constrictor. The Herpetological Bulletin 163: 35–36. DOI: 10.33256/hb163.3536
  19. Arzamendia V, Cisneros-Heredia DF, Fitzgerald L, Flores-Villela O, Gagliardi G, Giraudo A, Ines Hladki A, Köhler G, Lee J, Nogueira CdC, Ramírez Pinilla M, Renjifo J, Scrocchi G, Urbina N, Williams J, Wilson LD, Murphy J (2021) Boa constrictor. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2021-2.RLTS.T197462A2486405.en
  20. Dixon JR, Soini P (1986) The reptiles of the upper Amazon Basin, Iquitos region, Peru. Milwaukee Public Museum, Milwaukee, 154 pp.
  21. Frétey T (2019) Capitalised epithets in the works of Linnaeus (1758‒1767): findings and consequences in herpetology. Bionomina 16: 22–45. DOI: 10.11646/bionomina.16.1.2
  22. 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 Boa constrictor in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

ColombiaCaquetáFlorenciaMLS 2643; GBIF
ColombiaCaquetáLa MinaGutiérrez-Lamus et al. 2020
ColombiaCaquetáPuente Las MargaritasiNaturalist; photo examined
ColombiaCaquetáTres EsquinasMLS 1594; GBIF
ColombiaCaquetáVereda AzabacheiNaturalist; photo examined
ColombiaPutumayoPuerto AsísMLS 62; GBIF
ColombiaPutumayoRío PutumayoMVZ 33698; VertNet
ColombiaPutumayoVereda BellavistaiNaturalist; photo examined
ColombiaPutumayoVereda El RosaliNaturalist; photo examined
EcuadorMorona SantiagoCapadino EntzaiNaturalist; photo examined
EcuadorMorona SantiagoGualaquizaiNaturalist; photo examined
EcuadorMorona SantiagoLaberintos del ChiguazaiNaturalist; photo examined
EcuadorMorona SantiagoMacasPhoto by Darwin Núñez
EcuadorMorona SantiagoMacumaiNaturalist; photo examined
EcuadorMorona SantiagoMisión YaupiKU 192081; VertNet
EcuadorMorona SantiagoSawastianOrtega-Andrade 2010
EcuadorMorona SantiagoVía a comunidad ChinkianasiNaturalist; photo examined
EcuadorMorona SantiagoWisuiChaparro et al. 2011
EcuadorNapoChontapuntaiNaturalist; photo examined
EcuadorNapoCoca CodoiNaturalist; photo examined
EcuadorNapoDestacamento TiputiniNogueira et al. 2019
EcuadorNapoEl Carmen, 4 km S ofiNaturalist; photo examined
EcuadorNapoEl ReténiNaturalist; photo examined
EcuadorNapoGareno LodgePhoto by Sandro Aguinda
EcuadorNapoJatun Sacha Biological ReserveiNaturalist; photo examined
EcuadorNapoJondachi, 4 km W ofiNaturalist; photo examined
EcuadorNapoLa Casa del SuizoiNaturalist; photo examined
EcuadorNapoLimoncochaUF 30616; VertNet
EcuadorNapoMikunaiNaturalist; photo examined
EcuadorNapoMinga LodgeiNaturalist; photo examined
EcuadorNapoMisahuallíiNaturalist; photo examined
EcuadorNapoReserva Colonso ChalupasiNaturalist; photo examined
EcuadorNapoReserva NarupaiNaturalist; photo examined
EcuadorNapoReserva Río BigaiReptiles of Ecuador book database
EcuadorNapoRio Cotapino Alto NapoNogueira et al. 2019
EcuadorNapoRío JatunyacuiNaturalist; photo examined
EcuadorNapoRío PiatúaiNaturalist; photo examined
EcuadorNapoRío TenaiNaturalist; photo examined
EcuadorNapoTenaiNaturalist; photo examined
EcuadorNapoYachana ReserveWhitworth & Beirne 2011
EcuadorNapoYacuma EcolodgeiNaturalist; photo examined
EcuadorOrellanaChiru Isla, 7 km S ofiNaturalist; photo examined
EcuadorOrellanaEl CocaiNaturalist; photo examined
EcuadorOrellanaEstrella Yacu, 7 km NW ofiNaturalist; photo examined
EcuadorOrellanaHotel KareniNaturalist; photo examined
EcuadorOrellanaJivino Verde, 3 km S ofiNaturalist; photo examined
EcuadorOrellanaLaguna TaracoaiNaturalist; photo examined
EcuadorOrellanaMandaripanga campiNaturalist; photo examined
EcuadorOrellanaMaxus roadReptiles of Ecuador book database
EcuadorOrellanaNuevo ParaísoiNaturalist; photo examined
EcuadorOrellanaPlataforma Armadillo BNogueira et al. 2019
EcuadorOrellanaPompeya sur, 10 km S ofiNaturalist; photo examined
EcuadorOrellanaPozo Sacha-125Nogueira et al. 2019
EcuadorOrellanaRío Bigal Biological ReserveGarcía et al. 2021
EcuadorOrellanaRío SalvadoriNaturalist; photo examined
EcuadorOrellanaRío Tiputini, near Vía MaxusiNaturalist; photo examined
EcuadorOrellanaSaladero de pericosiNaturalist; photo examined
EcuadorOrellanaSan Jóse de PayaminoMaynard et al. 2017
EcuadorOrellanaSector Pozo Amo 1Nogueira et al. 2019
EcuadorOrellanaShiripuno LodgeOnline multimedia
EcuadorOrellanaTereréiNaturalist; photo examined
EcuadorOrellanaTiputini Biodiversity Station Cisneros-Heredia 2003
EcuadorOrellanaYarina Eco LodgeiNaturalist; photo examined
EcuadorOrellanaYasuní Scientific StationiNaturalist; photo examined
EcuadorPastazaArutamiNaturalist; photo examined
EcuadorPastazaBalsauraOrtega-Andrade 2010
EcuadorPastazaCascada Hola VidaPhoto by Danilo Medina
EcuadorPastazaCavernas del AnzuiNaturalist; photo examined
EcuadorPastazaConamboOrtega-Andrade 2010
EcuadorPastazaJardín Botánico Las OrquídeasiNaturalist; photo examined
EcuadorPastazaJuyuintzaOrtega-Andrade 2010
EcuadorPastazaKapawi LodgeReptiles of Ecuador book database
EcuadorPastazaKurintzaOrtega-Andrade 2010
EcuadorPastazaPastaza, CanelosiNaturalist; photo examined
EcuadorPastazaPindoyacuOrtega-Andrade 2010
EcuadorPastazaRío BufeoOrtega-Andrade 2010
EcuadorPastazaRío NushiñoiNaturalist; photo examined
EcuadorPastazaRío PintoyacuiNaturalist; photo examined
EcuadorPastazaSarayacuNogueira et al. 2019
EcuadorPastazaSumak Kawsay In SituBentley et al. 2021
EcuadorSucumbíos7 de JulioiNaturalist; photo examined
EcuadorSucumbíosCaiman LodgeReptiles of Ecuador book database
EcuadorSucumbíosCampamento Santa ElenaiNaturalist; photo examined
EcuadorSucumbíosCampamento Santa Elena, 2 km NW ofiNaturalist; photo examined
EcuadorSucumbíosCaño MandiiNaturalist; photo examined
EcuadorSucumbíosCascalesiNaturalist; photo examined
EcuadorSucumbíosCascales, 3 km N ofiNaturalist; photo examined
EcuadorSucumbíosComunidad Cofán DurenoiNaturalist; photo examined
EcuadorSucumbíosDuvino, 2 km NW ofiNaturalist; photo examined
EcuadorSucumbíosEl EnoNogueira et al. 2019
EcuadorSucumbíosJuan MontalvoiNaturalist; photo examined
EcuadorSucumbíosLa BarquillaiNaturalist; photo examined
EcuadorSucumbíosLago AgrioiNaturalist; photo examined
EcuadorSucumbíosLago Agrio, 7 km E ofKU 158787; VertNet
EcuadorSucumbíosLumbaquiiNaturalist; photo examined
EcuadorSucumbíosManos LabradorasiNaturalist; photo examined
EcuadorSucumbíosNapo Wildlife CenterReptiles of Ecuador book database
EcuadorSucumbíosPacayacuiNaturalist; photo examined
EcuadorSucumbíosPalmeras NorteiNaturalist; photo examined
EcuadorSucumbíosParque Ecológico de Lago AgrioiNaturalist; photo examined
EcuadorSucumbíosPlataforma Espejo 1Consultora Cinge 2012
EcuadorSucumbíosPuca PeñaiNaturalist; photo examined
EcuadorSucumbíosReserva CuyabenoiNaturalist; photo examined
EcuadorSucumbíosRío AguaricoiNaturalist; photo examined
EcuadorSucumbíosRío AguaricoMZB 2003-1751; VertNet
EcuadorSucumbíosRío CuyabenoiNaturalist; photo examined
EcuadorSucumbíosRío PuyacachiiNaturalist; photo examined
EcuadorSucumbíosRío San MigueliNaturalist; photo examined
EcuadorSucumbíosSacha LodgeiNaturalist; photo examined
EcuadorSucumbíosSan Pablo de Kantesiaya, 5 km SW ofiNaturalist; photo examined
EcuadorSucumbíosSan Pablo de KantesiyaNogueira et al. 2019
EcuadorSucumbíosSan Pedro de los CofanesiNaturalist; photo examined
EcuadorSucumbíosSanta Cecilia Duellman 1978
EcuadorSucumbíosSanta ElenaiNaturalist; photo examined
EcuadorSucumbíosShushufindiiNaturalist; photo examined
EcuadorSucumbíosSiona LodgeiNaturalist; photo examined
EcuadorSucumbíosTapir lodgeReptiles of Ecuador book database
EcuadorSucumbíosTerritorio Cofán DurenoYánez-Muñoz & Chimbo 2007
EcuadorSucumbíosVía ShuaraiNaturalist; photo examined
EcuadorTungurahuaRío VerdeiNaturalist; photo examined
EcuadorZamora ChinchipeReserva MaycuReptiles of Ecuador book database
EcuadorZamora ChinchipeShaimePhoto by Darwin Núñez
PeruAmazonasCaterpizaUSNM 566533; VertNet
PeruAmazonasLa PozaUSNM 566536; VertNet
PeruAmazonasPuerto GalileaUSNM 566534; VertNet
PeruAmazonasRío NajemMVZ 163374; VertNet
PeruLoretoIquitosTCWC 42062; VertNet
PeruLoretoReserva Pacaya SamiriaiNaturalist; photo examined
PeruLoretoSan RoqueiNaturalist; photo examined