Crocodile vs Alligator: Frequently Asked Questions

The clearest difference is the snout shape: alligators have a broad, U-shaped snout; crocodiles have a long, narrow, V-shaped snout. When the mouth is closed, only the upper teeth are visible on alligators. On crocodiles, both upper and lower teeth interlock and remain visible, including a prominent fourth lower tooth. Crocodiles also have functional salt glands allowing saltwater tolerance; alligators are confined to freshwater.

Yes, they are related but not as closely as their similar appearance suggests. Both belong to the order Crocodylia. Alligators and caimans form the family Alligatoridae. True crocodiles form the family Crocodylidae. The two families diverged approximately 80 million years ago during the late Cretaceous period.

The American alligator is found across the southeastern United States: Florida, Louisiana, Georgia, Alabama, Mississippi, South Carolina, North Carolina, Arkansas, Oklahoma, and Texas. Louisiana and Florida hold the largest populations, together accounting for approximately 3-4 million of the estimated 5 million US alligators. The Chinese alligator, a separate species, lives in the Yangtze River basin in China, with fewer than 300 wild individuals remaining.

Crocodiles (family Crocodylidae) are found on every warm continent except Europe. The American crocodile is the only species in the USA, confined to southern Florida. Nile crocodiles range across sub-Saharan Africa. Saltwater crocodiles span from India through Southeast Asia to northern Australia. The mugger crocodile occupies South Asia. In total, true crocodiles occupy around 90 countries.

Yes, but only in one location on Earth: the southern tip of Florida, specifically the Everglades, Florida Bay, and Biscayne Bay. American alligators dominate the freshwater interior. American crocodiles prefer the coastal saltwater and brackish zones. This is the only natural co-occurrence of the two families in the wild.

It depends on the species. The American alligator and American crocodile are similar in maximum size (up to 4.6 m). Saltwater crocodiles are the world's largest living reptile, reaching 6+ metres and 1,000 kg. Nile crocodiles reach 5.5 m. Chinese alligators are the smallest alligator at under 2 m. Black caimans can reach 5 m. Maximum size alone does not identify the species.

American alligators are opportunistic predators. Juveniles eat insects, fish, frogs, and small invertebrates. Adults eat fish, turtles, birds, snakes, and mammals. Large adults regularly eat deer, wild boar, and in documented cases, Florida panthers and black bears. Turtles are a dietary staple for large adults given the wide, flat jaw adapted for crushing hard shells.

Crocodile diet varies by species. All are primarily fish-eaters when smaller. Nile crocodiles eat wildebeest, zebra, cape buffalo, and other large mammals at river crossings. Saltwater crocodiles eat fish, birds, mammals up to water buffalo size, and any other large animal they can overpower. American crocodiles in Florida primarily eat fish, crustaceans, turtles, and small mammals.

The American alligator's maximum bite force is approximately 2,980 lbf (13,260 newtons), measured in the Erickson et al. 2012 PLOS ONE study. This is sufficient to shatter turtle shells and crush the bones of large mammals. It is the third-highest bite force measured among living animals, behind the saltwater crocodile (3,700 lbf) and Nile crocodile (3,100 lbf).

Saltwater crocodiles hold the record for the strongest measured bite of any living animal at approximately 3,700 lbf (16,460 newtons), from Erickson et al. 2012. Nile crocodiles measured up to 3,100 lbf. American crocodiles measured up to 2,100 lbf. Bite force scales with body size across all species.

American alligators live 35-50 years in the wild and up to 70+ years in captivity. Nile crocodiles are estimated at 45-100 years. Saltwater crocodiles may live up to 70 years in the wild. Like most ectotherms, their lifespan is difficult to determine precisely in wild populations. All large crocodilians are long-lived relative to most vertebrates.

The American alligator is IUCN Least Concern -- a conservation success story. From near-extinction in the 1960s, federal protection allowed the US population to recover to approximately 5 million. The Chinese alligator, however, is Critically Endangered with fewer than 300 wild individuals remaining in the Yangtze River basin.

Status varies by species. American crocodile: Vulnerable. Saltwater crocodile: Least Concern. Nile crocodile: Least Concern. Siamese crocodile: Critically Endangered (fewer than 1,000 remain). Cuban crocodile: Critically Endangered. Philippine crocodile: Critically Endangered. Mugger crocodile: Vulnerable. Overall, about 4 of the 14 true crocodile species are Critically Endangered or Endangered.

Yes, all crocodilians lay eggs. American alligators build vegetation mound nests and lay 32-46 eggs. Most crocodile species also build mound nests or dig holes in sandy banks. Clutch sizes range from 10-90 eggs depending on species. Incubation takes 60-90 days. Nest temperature determines offspring sex in all crocodilians -- higher temperatures produce males.

Saltwater crocodiles regularly cross open ocean, with verified journeys of 400-600 km using ocean currents. Nile crocodiles have colonised oceanic islands by sea crossing. American crocodiles use coastal saltwater and brackish water. American alligators occasionally enter saltwater briefly but cannot tolerate it long-term. No alligator species regularly swims in the open ocean.

Caimans are members of the family Alligatoridae, the same family as alligators, making them closer relatives of alligators than of crocodiles. Caimans are found in Central and South America only. Like alligators, they have a wide jaw with upper teeth covering the lower when the mouth is closed, and they lack functional salt glands. The spectacled caiman is distinguished by a bony ridge between the eyes; the black caiman can reach 5 metres.

Alligators and other crocodilians open their mouths while basking in a behaviour called gaping. This is thermoregulation -- releasing excess body heat. It is not a threat display when performed by a stationary, basking animal. Do not approach a basking alligator with an open mouth, but the open mouth alone does not indicate aggression toward humans.

In practice, geography is the first guide: alligators are only in the USA (and China). Caimans are in Central and South America. Visually, spectacled caimans have a bony interorbital ridge between the eyes that alligators lack. Black caimans are very dark and much larger. Yacare caimans have distinct black spotting on the jaw. If you are not in Florida, Texas, Louisiana, or the other SE US states, it is a caiman, not an alligator.

A gharial (Gavialis gangeticus) is the fourth crocodilian family, Gavialidae. It is found only in a few rivers of northern India and Nepal. It is distinguished by an extraordinarily long, thin, needle-like snout with approximately 110 interlocking teeth for catching fish. Adult males develop a bulbous nasal excrescence called a ghara. The gharial is Critically Endangered with approximately 650 wild individuals remaining, mainly in the Chambal River sanctuary.

It depends on species and jurisdiction. In the USA, spectacled caimans (Caiman crocodilus) are legally sold as pets in most states. American alligators and American crocodiles require federal and state permits and are heavily regulated. Saltwater crocodiles and Nile crocodiles are restricted or prohibited in most US states. The ownership of most crocodilian species requires permits. Check state and federal wildlife regulations before acquiring any crocodilian.