Reptilia · Squamata
Eunectes beniensisDirksen, 2002
Beni Anaconda
Photograph by Phil Whitehouse, CC BY, via Wikimedia Commons
A day-active, meat-eating snake from the Neotropic region, reaching 400 cm nose to tail.
Reptilia › Squamata › Boidae › Eunectes
- Grows to
- 4000mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Diurnal
- Weighs up to
- 12,685g
- greatest
Longer than 92% of all boas anyone has measured.
The bar is the rank itself: its length is the share of the family this animal exceeds. The chart below is the family’s real spread, on a logarithmic scale because body length here runs from 109 to 6,700 mm. The solid rule is this animal. Every bar is a count of real species, and nothing on this figure is estimated.
What is known
26 sourced facts, each taken from a named scientific dataset. How to read these.
Cited from a dataset unless a row is marked otherwise.
Standing in the world
- Still living
- Extant
- Conservation status
- Least Concern
- Status assessed · the year the Red List last looked
- 2014
The animal itself
- Limbs
- None
- Venomous
- No
Size
- Length snout to vent · greatest recorded
- 2880mm9 ft 5 in
- Length snout to vent · adult female mean
- 2340mm7 ft 8 in
- Length nose to tail · greatest recorded
- 4000mm13 ft 1 in
- Body mass · greatestcomputed
- 12,685g28 lb
4000 mm total length (Feldman et al. 2016, Dirksen and Bohme 2005 - who's actual data has a maximum of 320 cm total length and 283 cm SVL), Max SVL 235.3 (De la Quintana et al. 2017), max total length 217 and 324 cm for males and females, respectively, in the supplement 2 females, 1800, 2880 mm SVL, 3 males 1340-1845 mm, mean 1565 mm SVL (Tarkhnishvili et al. 2022)
snakes only in this source
computed from length by a family-level allometric equation, not weighed
How it lives
- Dietcomputed
- Carnivorous
- Active
- Diurnal
- Habitat
- Forest, Savanna, Wetlands
- Biome
- Tropical & Subtropical Grasslands, Savannas & Shrublands
- Region
- Neotropic
- Mainland or island
- Mainland
- Elevation · above sea level
- 115–350m
- Range size
- 221,615km²
- Home range · largest recorded
- 394,000m2
no actual data but can be imputed as carnivorous like all snakes
IUCN (115 to 350)
Breeding
- Reproduction
- Viviparous
Feldman et al. 2015
Naming and history
- Suborder
- Serpentes
- Infraorder
- Alethinophidia
- Subspecies
- No
- Described by
- Dirksen
- Moved to another genus · since it was first described
- No
- Described in
- 2002
- Type locality
- Bolivia
Keeping one
13 ft 1 in × 6 ft 7 in × 9 ft 10 in(400 × 200 × 300 cm)
Minimum length × width × height, for one animal. Bigger is always better.
The standard sizes snakes as a fraction of total length: 1 × 0.5 × 0.75.
Mindestanforderungen an die Haltung von Reptilien (Sachverständigengutachten), German Federal Ministry for Nutrition, Agriculture and Forestry, Animal Welfare Division, 10 January 1997. The standard states these floor areas are recommendations rather than binding limits.
From this animal’s own total length of 13 ft 1 in (4000 mm), at 1 × 0.5 × 0.75 times it, following the German federal welfare standard — how this is worked out.
No preferred body temperature has been recorded for Beni Anaconda. Rather than repeat a number from a care sheet, this page leaves it out.
Feeding
A prey item should be between the same width as the widest part of the snake's body and about 1.5 times that width.
Widely used across snake husbandry references. An alternative formulation gives prey at 10-15% of the snake's body mass. This is established practice, not a measurement.
871kJ per day
Worked out for an animal of 12,685 g, the heaviest recorded for Beni Anaconda — so it is the top of the range, not a figure for a particular animal. Weigh yours and the number will be lower.
An upper estimate, not a feeding target, and not veterinary advice. The equation covers only what an animal burns staying alive, so a growing, gravid or recovering animal needs more — and it was measured on wild animals, which move far more than one in an enclosure. Body condition and a vet who knows the species are what a feeding decision should rest on. Where this comes from.
What nobody knows
These are not gaps in our research. No scientific dataset records them for this species — and saying so is information you cannot get from a reference that simply leaves a field out.
- — Length snout to vent · adult male mean
- — Length snout to vent · adult mean
- — Female length · mean, nose to tail
- — Length nose to tail · adult male mean
- — Length nose to tail · adult mean
- — Largest female · snout to vent
- — Largest male · snout to vent
- — Largest female · shell length
- — Largest male · shell length
- — Hatchling length · snout to vent
- — Hatchling length · nose to tail
- — Largest juvenile · snout to vent
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · a typical adult
- — Body mass · adult female, mean
- — Body mass at hatching
- — Longest recorded life
- — Preferred body temperature · chosen in a laboratory gradient
- — Body temperature when active · measured in the wild
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How it hunts
- — Where it lives
- — How the young develop
- — Gestation or incubation
- — Average clutch
- — Smallest clutch recorded
- — Largest clutch recorded
- — Mean clutch · smallest reported
- — Mean clutch · largest reported
- — Clutches in a year
- — Clutches a year · fewest
- — Clutches a year · most
- — First breeds from · youngest recorded
- — First breeds by · oldest recorded
- — Hatchling length · smallest recorded
- — Hatchling length · largest recorded
- — Age at first breeding · female
- — Mature from · youngest recorded
- — Mature by · oldest recorded
- — Size at maturity · smallest recorded
- — Size at maturity · largest recorded
- — Fangs
- — Body temp in the wild · lowest mean recorded
- — Body temp in the wild · highest mean recorded
- — Colour on the back
- — Pattern on the back
- — Pupil
- — Sex decided by
- — Population trend
- — Red List criteria
- — Active season · shortest recorded
- — Active season · longest recorded
- — Density · lowest recorded
- — Density · highest recorded
- — Active in
Others in Boidae
Take this data
Everything on this page is available as data under CC BY 4.0 — use it freely, credit it, no permission needed.
This species as JSON · the whole dataset
Cite this page
The Reptile & Amphibian Encyclopedia (2026). Eunectes beniensis. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/eunectes-beniensis
@misc{eunectes_beniensis_2026,
title = {Eunectes beniensis},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/eunectes-beniensis}
}Sources
- Moura, M. R. et al. TetrapodTraits: a database of 33,281 tetrapod species. Used under CC BY 4.0. Observed values only; this encyclopedia does not publish its imputed predictions.
- Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
- Catalogue of Life (dataset 3LR), used under CC BY.
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.