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Some federal rules apply In-depth sheet

American alligator

Alligator mississippiensis

Also known as Gator, Pike-headed alligator, Alligator

Reptiles › Alligators and caimans (Crocodylia) › Alligatoridae (Alligators and caimans)

American alligators grow large (females about 8.5–10 ft, males usually 11–12 ft and exceptionally near 15 ft) and can live about 50 years in captivity. Cute hatchlings become dangerous adults; Clint's Reptiles scores them 2.6/5.

Zoos & aquariums

Experience: Expert / facility

Adult length8–12 ft

Lifespanabout 50 years in care

ActiveDay and night

DietCarnivore

Warnings

Mostly kept by zoos, public aquariums, sanctuaries or licensed facilities. The guide below describes professional husbandry so you can understand the animal, not as encouragement to keep one privately.

Care guide

Growth

Males grow fast until about 20 years old, reaching about 11.5 ft; females average about 8.4 ft.

Sources 78

Care

Large, well-filtered water and a warm basking spot are the basics; size makes handling dangerous.

Sources 112

Show the group care guide for crocodilians

Group care guide

Crocodilians

Applies to most species in this group. Habitat: Tropical and subtropical wetlands. Individual species can differ, so compare with the species numbers above and the linked sources.

Most crocodilians need state dangerous-wildlife permits; many states ban them for private keepers.

Housing & setup

Very large, heated indoor-outdoor facilities with deep pools, haul-out areas and double-secure fencing.
Water quality and temperature control are critical.

Sources 113 114 138

Climate & lighting

Basking spot	90–95°F
Water	78–84°F

UVB: Recommended.

Sources 113 114 138

Diet

Whole prey: fish, rodents and poultry, with vitamin and mineral supplementation.

Sources 113 114 138

Health watch

Bites and tail strikes cause serious injury.
Dwarf caimans stay smaller (4–5 ft) but are still powerful and long-lived.

Sources 113 114 138

Understanding the animal

In the wild

Researched for this exact species, not its family. Good care copies these conditions.¹²³

Where it lives	Swamps, marshes, ponds, lakes and rivers of the southeastern United States. Smaller animals use sheltered wetland margins; adults also use open water and banks.
Ground it lives on	Muddy banks and wetland soil; excavated holes and terrestrial nesting sites.
Water it lives in	Mainly freshwater, still or slow-flowing rivers, swamps, marshes and lakes; brackish or saline exposure is temporary because it lacks salt glands. Wild chemistry and temperature ranges were not established.
Climate	Southeastern temperate to subtropical conditions with seasonal winter cooling and occasional drought; uses excavated refuges in extreme weather. Measured temperature and humidity ranges were not established.
Active	Cathemeral: daytime basking and nighttime breeding activity are documented; cold weather produces seasonal dormancy (brumation).
Social life	Territorial adults can aggregate; hatchlings remain together under maternal protection.
Wild diet	Young eat small fish, insects and other invertebrates; larger animals take fish, mammals, reptiles and birds.
Behavior to plan for	Swims, excavates refuge holes and walks on land. Its size, predatory behavior and powerful jaws require protected management.

What this means for care

Provide both substantial freshwater swimming space and accessible land.
Include sheltered margins for small animals and refuges from exposure.
Plan separation around territoriality and large size differences.

Native climate (measured)

Warm-season highs	about 91°F (up to 92°F in the hottest sampled areas)
Cool-season lows	about 50°F (down to 42°F in the coldest sampled areas)
Average temperature	68–75°F across sampled records
Relative humidity	72–74% on average (driest month about 69%)
Rainfall	about 1289 mm a year

Measured at 134 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.

Profile

Researched for this exact species. Sources are listed under In the wild above.

History

The American alligator is native to North America and the southeastern United States. The supplied Animal Diversity Web source also notes short-lived occurrences outside its native range after formerly captive animals were released.

Keeper tips

Provide both aquatic and terrestrial areas rather than treating the species as completely aquatic.
Base the aquatic environment primarily around freshwater rather than saltwater.
Include sheltered or vegetated areas in addition to open water.
Account for the enormous adult size described for the species when planning space.
Expect bellowing and territorial communication, particularly around the breeding season.

Behaviors reported

Creates alligator holes by excavating mud or soil with the snout and tail.
Bellowing is used to advertise territory and find mates.
Males use infrasound to attract females.
Mothers guard nests and may carry hatchlings to water in their mouths.
Parental care can continue well beyond hatching.

Unique adaptations

It tolerates cooler climates better than the American crocodile.
Its broad U-shaped snout distinguishes it from the sympatric American crocodile.
Young have yellow body bands.
Excavation of gator holes provides refuge from drought and irregular weather.

Remarkable facts

Adult males commonly reach about 11 to 12 ft, with exceptional males near 15.7 ft, and may weigh up to about 1,000 lb.
Females are smaller, at about 8.5 to 11 ft.
It is the crocodilian with the northernmost natural distribution according to the supplied Animal Diversity Web source.
It functions as an apex predator.
Its alligator holes act as wet and dry habitat for other organisms, making the species an ecosystem engineer.
Its natural distribution extends from areas of North Carolina south through Florida and west to central Texas, with additional populations in several southeastern states.

From the sources

Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.

Overview	The American alligator (Alligator mississippiensis), sometimes referred to as a common alligator or just gator, is a large crocodilian reptile native to the Southeastern United States. It is one of the two extant species in the genus Alligator, and is larger than the only other living alligator species, the Chinese alligator. Adult male American alligators measure 3.4 to 4.8 m in length, and can weigh up to 450 kg, with unverified sizes of up to 5.84 m and weights of 1000 kg making it the heaviest member of the family Alligatoridae, and the second longest one, after the black caiman. — Wikipedia (community-edited)
Where it lives	Although sometimes found in brackish water settings, the American alligator is most commonly found in freshwater environments of the temperate region due to its low tolerance for salt. — Animal Diversity Web
Reproduction	Oviparous; temperature-dependent sex determination (TSD, see Valenzuela & Lance 2004 for details). — The Reptile Database
Appearance and size	As a hatchling, an alligator is typically 22.9 cm long. — Animal Diversity Web
History and naming	Named after the type locality. — The Reptile Database

Data and studies

The numbers

Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.

Lifespan in care

Reported50–73years

Animal Diversity Web 7850–73

Maximum recorded lifespan

Highest reported85years

AnAge 16277

Myhrvold et al. 16385

Longest recorded lifespan reported by each database; typical lifespans are usually shorter. The AnAge record comes from an animal in human care.

Typical adult weight

Average of sources234lb

AnAge 162331

Myhrvold et al. 163137

Average adult body mass in each database (FishBase gives the maximum recorded weight).

Clutch size

Reported39.7eggs

Myhrvold et al. 16339.7

Average per litter or clutch.

Incubation

Reported65days

Myhrvold et al. 16365

Female maturity

Average of sources12.3years

AnAge 16212

Myhrvold et al. 16312.6

Veterinary & husbandry research

Steatitis and fat necrosis in captive alligators Larsen RE et al., Journal of the American Veterinary Medical Association 1983
Pathology of experimental mycoplasmosis in American alligators Brown DR et al., Journal of wildlife diseases 2001
Detection of West Nile virus RNA in mosquitoes and identification of mosquito blood meals collected at alligator farms in Louisiana Unlu I et al., Journal of medical entomology 2010
Parental exposure to pesticides and poor clutch viability in American alligators Rauschenberger RH et al., Environmental science & technology 2007

Peer-reviewed papers that mention this species alongside captivity, zoos, veterinary care or aquaculture. Some cover several species or mention it only in passing, so check the abstract. See all 45 on PubMed → 170

Federal legal snapshot

Some federal rules apply

Endangered Species Act: threatened (similarity of appearance). Listed only because it looks like protected species, not because it is endangered itself. A special rule (50 CFR 17.42) replaces the usual ESA permits: legally obtained or captive-bred animals can be bought, sold and shipped with the required state tags and paperwork. State rules still apply and are often strict. 179
CITES Appendix II. Appendix II: international trade needs CITES export permits. CITES doesn't restrict buying a captive-bred animal within the U.S.; keep your purchase records. 173 186

State law decides most of it. Each state sets its own permits and bans for exotic, native, venomous and dangerous animals, and cities and counties can be stricter. Find your state agency →

Not covered by the Animal Welfare Act

The Act only covers warm-blooded animals. Reptiles, amphibians, fish and invertebrates have no federal care standards, even at licensed facilities; state and local rules may still apply.

Kept in captivity?

Every species on this site needs evidence that people actually keep it. For this one:

Included in our hand-checked list of animals kept as pets, livestock or in zoos
AnAge has a longevity record from an animal in captivity
Reviewed by Clint's Reptiles
Covered by one of our in-depth care sheets
2634 iNaturalist observations of captive animals

Clint's Reptiles rating

2.6/ 5 overall

Handleability1/5

Care3/5

Hardiness5/5

Availability3/5

Upfront cost1/5

From Clint Laidlaw's "The Best Pet?" review: American Alligator, The Best Pet Crocodilian?. Higher care and upfront-cost scores mean easier and cheaper. Watch the video →

Sources for this sheet

Animal Diversity Web (University of Michigan): Alligator mississippiensis Zoo, university or veterinaryUniversity-hosted species account, mostly wild biology.
Clint's Reptiles (YouTube): American Alligator, The Best Pet Crocodilian? Expert educator & keeperClint Laidlaw, PhD in Biology Education and MS in Evolutionary Ecology; owner of Clint's Reptile Room and a longtime keeper. Rates each species on handleability, care, hardiness, availability and upfront cost.
AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources) Peer-reviewed researchCurated, referenced longevity and life-history records for thousands of species; maximum lifespans are often from zoo animals.
Myhrvold et al. (2015). An amniote life-history database. Ecology 96: 3109 Peer-reviewed researchPeer-reviewed compilation of life-history data for over 21,000 birds, mammals and reptiles.
50 CFR 17.11: Endangered and threatened wildlife Zoo, university or veterinaryCurrent federal Endangered Species Act list.
Species+ (UNEP-WCMC and the CITES Secretariat) Zoo, university or veterinaryThe official database of species listed under CITES.
USFWS International Affairs: CITES Zoo, university or veterinaryFederal agency that issues CITES permits.
Merck Veterinary Manual: Management and husbandry of reptiles Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
Merck Veterinary Manual: Nutritional, metabolic and endocrine diseases of reptiles Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
Merck Veterinary Manual: Management of zoo animals Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
Clint's Reptiles (YouTube): American Alligator, The Best Pet Crocodilian? Expert educator & keeperClint Laidlaw, PhD in Biology Education and MS in Evolutionary Ecology; owner of Clint's Reptile Room and a longtime keeper. His "Best Pet?" series reviews each species' care in depth.
The Reptile Database Peer-reviewed researchScientist-curated catalog of every reptile species, with taxonomy and literature.
GBIF Backbone Taxonomy (Global Biodiversity Information Facility) Peer-reviewed researchInternational scientific taxonomy used here for classification.
Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.
iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.