Alligator vs Crocodile: What’s the Difference?
The main difference between alligators and crocodiles is the snout and teeth: alligators have a broad, U-shaped snout that hides the lower teeth, while crocodiles have a narrower, V-shaped snout with teeth showing even when the mouth is shut. Alligators prefer fresh water and live only in the United States and China; crocodiles tolerate salt water and occur across the tropics.
| American Alligator | Saltwater Crocodile | |
|---|---|---|
| Scientific name | Alligator mississippiensis | Crocodylus porosus |
| Lifespan | 35–50 years in the wild | 50–70 years (estimated) estimated in the wild |
| Weight | 90–450 kg (200–1,000 lb) | males 400–1,000 kg (880–2,200 lb); females 80–150 kg (180–330 lb) |
| Size | 2.5–4.5 m (8–15 ft) (length) | 2.5–5 m (8–16 ft) (length) |
| Top speed | 32 km/h (20 mph) | 24–29 km/h (15–18 mph) |
| Gestation / incubation | about 65 days | 80–90 days |
| Diet | Carnivore | Carnivore |
| Family | Alligatoridae | Crocodylidae |
| Habitat | Freshwater swamps, Marshes, Slow rivers, Lakes and ponds, Brackish wetlands | Estuaries, Mangrove swamps, Tidal rivers, Freshwater billabongs and swamps, Coastal seas |
| IUCN status | Least Concern | Least Concern |
Figures shown are for the american alligator (Alligator mississippiensis) and the saltwater crocodile (Crocodylus porosus).
Key differences
Snout shape
Seen from above, an alligator's snout is wide and rounded like the letter U, a shape suited to crushing turtles and other hard prey. Most crocodiles have a longer, more pointed V-shaped snout. The difference is obvious in the two example species here, the American alligator and the saltwater crocodile, although a few crocodile species have fairly broad snouts.
Teeth
When an alligator closes its mouth, its wide upper jaw covers the lower teeth, so you mostly see a row of upper teeth pointing down. A crocodile's jaws are about the same width, so upper and lower teeth interlock and stay visible. The large fourth tooth on each side of the lower jaw is especially easy to spot.
Salt tolerance
Crocodiles have working salt glands on the tongue that get rid of excess salt, so many species live in estuaries, mangroves and even the open sea. Saltwater crocodiles regularly travel between islands. Alligators have much weaker salt glands and stick mainly to freshwater swamps, rivers and lakes, entering brackish water only for short periods.
Where they live
There are only two alligator species: the American alligator of the southeastern United States and the critically endangered Chinese alligator. True crocodiles are far more widespread, with species in Africa, Asia, Australia and the Americas. Southern Florida is the only place where alligators and crocodiles live side by side in the wild.
Color
Adult American alligators are dark, usually blackish or deep gray, which helps them absorb heat in cooler climates. Crocodiles tend to be lighter, in shades of olive, tan or gray-green, often with darker bands or mottling. Color varies with water quality and algae, so it should be used as a supporting clue rather than the main one.
Temperament
Saltwater and Nile crocodiles are widely considered the most dangerous crocodilians and are responsible for the great majority of fatal attacks on people worldwide. American alligators are generally warier of humans, and serious attacks are rare, though they do happen. Any large crocodilian is a powerful predator and should be given plenty of space.
How to tell them apart
- Check the snout from above: a broad, rounded U shape means alligator, while a narrower, pointed V shape means crocodile.
- Look at the closed mouth. If lower teeth are clearly visible, especially a big fourth tooth, it is a crocodile.
- Dark, almost black skin suggests an alligator; olive or tan skin suggests a crocodile.
- Consider the location. In the United States outside southern Florida, a wild crocodilian is an alligator.
What they have in common
Alligators and crocodiles are both members of the order Crocodylia, an ancient group that also includes caimans and gharials. They share armored skin, a powerful tail, eyes and nostrils set high on the head, and a four-chambered heart. Both are ambush predators, both lay eggs in nests the mother guards, and the nest temperature determines the sex of the hatchlings.
Frequently asked questions
Which is more dangerous, an alligator or a crocodile?
Crocodiles are more dangerous overall. Saltwater and Nile crocodiles are large, territorial and account for most fatal crocodilian attacks worldwide. American alligators seldom attack people unless they have been fed or provoked, though they are fully capable of killing an adult, so they should never be approached.
Can alligators and crocodiles interbreed?
No. Alligators and crocodiles belong to different families, Alligatoridae and Crocodylidae, which split tens of millions of years ago. They are too genetically distant to produce offspring, even in southern Florida where American alligators and American crocodiles share the same habitat.
Who would win, an alligator or a crocodile?
Size would probably decide it. The saltwater crocodile is the largest living reptile and grows considerably bigger and heavier than the American alligator, so a full-grown male would have a clear advantage. The two species never meet in the wild, since they live on opposite sides of the world.
Are there crocodiles in Florida?
Yes. The American crocodile lives in coastal southern Florida, including the Everglades and the Florida Keys. It is a different species from the saltwater crocodile and is shy and uncommon. Florida is the only place on Earth where wild alligators and crocodiles coexist.