Reptilia · Squamata
Agkistrodon piscivorusLacépède, 1789
Cottonmouth
Photograph by William J. Deml, CC BY, via iNaturalist
A water-living, active by day or night, meat-eating snake from the Nearctic region, reaching 189 cm nose to tail.
Also called Cotton-mouth, Eastern Cottonmouth, Northern Cottonmouth.
Reptilia › Squamata › Viperidae › Agkistrodon
- Grows to
- 1892mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives up to
- 24.6years
Longer than 94% of all vipers 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 280 to 3,900 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
48 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
- 2007
- Population trend
- Stable
The animal itself
- Limbs
- None
- Colour on the back
- Black
- Pupil
- Vertical slit
- Venomous
- Yes
- Fangs
- At the front of the mouth
- Longest recorded life
- 24.6years
- Preferred body temperature · chosen in a laboratory gradientmeasured
- 21.7°C
- Body temperature when active · measured in the wild
- 26.2°C79 °F
- Body temp in the wild · mean, when active
- 26.2°C
Stark et al. 2020
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 580mm23 in
- Length nose to tail · greatest recorded
- 1892mm6 ft 2 in
- Hatchling length · nose to tail
- 250mm9.75 in
- Largest juvenile · snout to vent
- 350mm14 in
- Body mass · greatestcomputed
- 3333g7.3 lb
- Body mass · a typical adult
- 1700g3.7 lb
- Body mass at hatchingmeasured
- 10.5g0.37 oz
snakes only in this source
computed from length by a family-level allometric equation, not weighed
AnAge rates this record "acceptable"
How it lives
- Diet
- Carnivorous
- How it hunts
- Active foraging
- Active
- Cathemeral
- Where it lives
- Aquatic
- Habitat
- Forest, Marine Coastal, Marine Intertidal, Shrubland, Wetlands
- Biome
- Temperate Broadleaf & Mixed Forests
- Region
- Nearctic
- Mainland or island
- Mainland
- Highest it lives · above sea level
- 700m
- Range size
- 1,501,974km²
Amphibians, Fish (Ramirez et al. 2023)
Active (Camper 2019)
Stark et al. 2018
Scharf et al. 2015, Guyer et al. 2019, O'Shea 2018
throughout Coastal Plain and lower Piedmont (Camper 2019), 0-700 (O'Shea 2018)
Breeding
- Reproduction
- Viviparous
- Sex decided by
- Genes, ZW/ZZ
- Gestation or incubation
- 152days
- Average clutch
- 7eggs
- Eggs or young per clutch
- 1–16eggs
- Mean clutch
- 5.5–7eggs
- Clutches in a year
- 0.5per year
- Egg length
- 50mm2 in
- Egg width
- 25mm1 in
- First breeds at
- 24–36months
- Age at first breeding · female
- 1095days
Feldman et al. 2015, Meiri et al. 2019
3-9 mean=5.5. (Camper 2019), means: 6-7 (Guyer et al. 2019), 4-11 (O'Shea 2011, O'Shea 2018), 5-11 (Beane et al. 2010), 1-16 (Murphy et al. 2003), 3-8 (Phillips et al. 2022)
Naming and history
- Suborder
- Serpentes
- Infraorder
- Alethinophidia
- Subspecies
- No
- Described by
- Lacépède
- Moved to another genus · since it was first described
- Yes
- Described in
- 1789
- Type locality
- USA
Keeping one
6 ft 2 in × 3 ft 1 in × 4 ft 8 in(189 × 95 × 142 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.
Spends time in water, so a water area is part of the enclosure rather than a dish.
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 6 ft 2 in (1892 mm), at 1 × 0.5 × 0.75 times it, following the German federal welfare standard — how this is worked out.
In a laboratory thermal gradient this species settled at 71 °F (21.7 °C).
Preferred body temperature, recorded in a laboratory gradient where the animal could choose freely. 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.
265kJ per day
Worked out for an animal of 3,333 g, the heaviest recorded for Cottonmouth — 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 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 · shell length
- — Body mass · adult female, mean
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How the young develop
- — Clutches a year · fewest
- — Clutches a year · most
- — 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
- — Pattern on the back
- — Red List criteria
- — Active season · shortest recorded
- — Active season · longest recorded
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Active in
- — Lowest it lives · above sea level
Others in Viperidae
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). Agkistrodon piscivorus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/agkistrodon-piscivorus
@misc{agkistrodon_piscivorus_2026,
title = {Agkistrodon piscivorus},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/agkistrodon-piscivorus}
}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.