Squamata · BoidaeEntry 2,738 of 21,572

Reptilia · Squamata

Boa constrictorLinnaeus, 1758

Red-Tailed Boa Constrictor

Photograph by Charles J. Sharp, CC BY-SA, via Wikimedia Commons

An active by day or night, meat-eating snake from the Neotropic region, reaching 364 cm nose to tail.

Also called Argentine Boa Constrictor, Atlantic Boa, Dominican Boa Constrictor.

Reptilia › Squamata › Boidae › Boa

Grows to: 3640mm; greatest recorded
Eats: Carnivorous
Active: Cathemeral
Lives up to: 40.4years

Body length across Boidae

Longer than 90% of all boas anyone has measured.

90% of 63 species are smaller10% larger

109 mmthe whole family, smallest to largest6,700 mm

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

43 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
Population trend: Decreasing

The animal itself

Limbs: None
Venomous: No
Longest recorded life: 40.4years
Body temperature when active · measured in the wild: 23.04°C73 °F
Body temp in the wild · mean, when active: 12.2–34°C54–93 °F

Size

Length snout to vent · greatest recorded: 1662mm5 ft 5 in
Length nose to tail · greatest recorded: 3640mm11 ft 11 in
Hatchling length · nose to tail: 495mm19.5 in
Body mass · greatestcomputed: 19,253g42 lb
Body mass · a typical adult: 3532g7.8 lb
Body mass at hatchingmeasured: 77.5g2.7 oz

How it lives

Diet: Carnivorous
How it hunts: Mixed
Active: Cathemeral
Where it lives: Arboreal, terrestrial
Habitat: Forest, Savanna
Biome: Tropical & Subtropical Moist Broadleaf Forests
Active season · months of the year: 12months
Region: Neotropic
Mainland or island: Mainland
Highest it lives · above sea level: 1500m
Range size: 13,080,691km²

Breeding

Reproduction: Viviparous
Sex decided by: Genes, XX/XY
Gestation or incubation: 125days
Average clutch: 23eggs
Eggs or young per clutch: 6–65eggs
Mean clutch: 21.4eggs
Clutches in a year: 1per year
Clutches a year: 0.75per year
First breeds at: 42months
Age at first breeding · female: 1095days

Naming and history

Suborder: Serpentes
Infraorder: Alethinophidia
Subspecies: Boa constrictor constrictor LINNAEUS 1758 Boa constrictor longicauda PRICE & RUSSO 1991 Boa constrictor occidentalis PHILIPPI 1873 Boa constrictor ortonii COPE 1877
Described by: Linnaeus
Moved to another genus · since it was first described: No
Described in: 1758
Type locality: Indiis

Keeping one

11 ft 11 in × 6 ft × 17 ft 11 in(364 × 182 × 546 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 × 1.5.

Recorded both on the ground and climbing, so this is the larger of the two rules in every dimension.

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 11 ft 11 in (3640 mm), at 1 × 0.5 × 1.5 times it, following the German federal welfare standard — how this is worked out.

Active animals measured in the wild averaged 73 °F (23 °C).

Mean body temperature of active individuals measured in nature. A measurement of the animal, not a setting for a thermostat.

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.

1262kJ per day

Worked out for an animal of 19,253 g, the heaviest recorded for Red-Tailed Boa Constrictor — 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.

Morphs

0 with peer-reviewed genetics behind them, 10 resting on breeder consensus. Most references present both with the same confidence.

What each pairing produces → · Two genes at once →

Anerythristic Type Ibreeder consensus
Red and orange pigment absent, leaving a grey, brown and black animal.
Worth knowing. As with the albinos, there is more than one anerythristic line. Type I and Type II are different genes and pairing them produces no anerythristic young.
Anerythristic Type IIbreeder consensus
A separate anerythristic line, often browner than Type I and holding more pattern.
Arabesquebreeder consensus
Saddles drawn into fine connected scrollwork running down the back.
Bloodbreeder consensus
Deep red ground colour, built up over generations by choosing the reddest animals rather than carried by one gene.
Hypomelanisticbreeder consensus
Reduced black pigment, giving a cleaner, brighter animal that keeps its pattern. Two copies produce a Super Hypo, lighter again.
Junglebreeder consensus
Pattern broken and thrown out of line, often asymmetrically, with wide saddles.
Kahl Albinobreeder consensus
No black pigment, leaving cream, orange and pink with red eyes.
Worth knowing. There are two separate albino lines in boas, Kahl and Sharp, and they are different genes. A Kahl albino bred to a Sharp albino produces normal-looking young — each carrying one copy of each gene, and not one of them albino. Check which line an animal comes from before pairing it.
Leopardbreeder consensus
Pattern broken into fine speckling, with a pale ground and dark head markings.
Motleybreeder consensus
Saddles joined and drawn out along the back, with clean flanks.
Sharp Albinobreeder consensus
A separate albino line, keeping more yellow and less pink than the Kahl form, with darker eyes.
Worth knowing. Not compatible with the Kahl albino. The two lines arose independently and sit at different loci, so pairing them produces no albino offspring at all.

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 female mean
— 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
— Largest juvenile · snout to vent
— Largest juvenile · shell length
— Egg length
— Egg width
— Body mass · adult female, mean
— Preferred body temperature · chosen in a laboratory gradient
— Eats arthropods
— Eats vertebrates
— Eats plant matter
— How the young develop
— Hatchling length · smallest recorded
— Hatchling length · largest recorded
— Mature from · youngest recorded
— Mature by · oldest recorded
— Size at maturity · smallest recorded
— Size at maturity · largest recorded
— Fangs
— Colour on the back
— Pattern on the back
— Pupil
— Red List criteria
— Density · lowest recorded
— Density · highest recorded
— Home range · largest recorded
— Active in
— Lowest it lives · above sea level

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). Boa constrictor. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/boa-constrictor

@misc{boa_constrictor_2026,
  title  = {Boa constrictor},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/boa-constrictor}
}

Sources

Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
AnAge, Human Ageing Genomic Resources (de Magalhães et al.), used under CC BY 3.0.
Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
Catalogue of Life (dataset 3LR), used under CC BY.