Alligators are so abundant in the wetlands of Florida that the Florida legislature named one species, the American alligator (Alligator mississippiensis), the Florida state reptile in 1987. While the American alligator favors Florida and the wetlands of other Southeastern states, the Nile crocodile (Crocodylus niloticus) inhabits the rivers and lakes of 47 countries in Africa. At first glance, alligators and crocodiles appear similar; but if you look at the details of each species, you can understand the differences between these two huge reptiles.
Although American alligators and Nile crocodiles belong to the same reptilian class and the order crocodylia, their families are different. American alligators belong to family Alligatoridae, Nile crocodiles to family Crocodylidae. American crocodiles also go by the names Florida alligators, Mississippi alligators, Louisiana alligators or just 'gators. There are at least as many common names for the Nile crocodile as there are languages spoken in Africa.
One of the most striking differences between the American alligator and Nile crocodile is size. Florida’s state alligator can weight from 450 to 600 pounds and averages 13 feet long, while the Nile crocodile weighs 150 to 220 pounds and averages about 8 feet long. Snout size is also different in these two reptiles. The American crocodile has a short, rounded snout in contrast to the Nile crocodile's, which has a triangular snout that tapers from the nose to the back of the head. The teeth of the these two reptiles are different; the alligator’s large fourth tooth situated on each side of the bottom jaw fits into a pocket in the top jaw, so it is invisible when the alligator closes his mouth. The Nile crocodile’s large fourth tooth, also located on each side of the bottom jaw, sits outside the mouth, overlapping the top jaw when the crocodile’s mouth is closed. The eyes of the American alligator are silver; the Nile crocodile’s green. Another way to tell the two apart is skin color. Most alligators have black skin compared with the olive green, brown or gray skin of the Nile crocodile. The Florida alligator's belly is cream-colored; the crocodile’s belly is yellow.
American alligators are widespread in Florida, as well as in Louisiana, the Carolinas, Georgia, Alabama and parts of southern Texas. Gators thrive in swamps, bayous, rivers, lakes and ponds. Nile crocodiles make their home in the rivers, lakes and swamps of Africa.
An assortment of small prey, such as lizards, fish, shellfish, snakes, birds, small mammals and turtles compose the American alligator’s diet. The Nile crocodile eats small prey like fish, birds and turtles but attacks large mammals for sustenance as well. The crocodile waits underwater for prey such as buffalo, antelope and hippos to enter the water, then attacks, dragging the large animals underwater to drown them.
- San Diego Zoo: Nile Crocodile, Crocodylus Niloticus
- The IUCN Red List of Threatened Species: Crocodylus Niloticus
- The IUCN Red List of Threatened Species: Alligator Mississippiensis
- Animal Diversity Web: Alligator Mississippiensis
- National Parks Conservation Association: American Alligator
- Crocodilian Species List: Crocodylus Niloticus
- Anup Shah/Digital Vision/Getty Images