What is the real difference between a crocodile and an aligator?

Answer 1

The first difference between a crocodile and an alligator is that they are from different families of crocodilians. Crocodiles are from the crocodylidae family, while alligators and caiman are from the alligatoridae family.

In terms of physical differences the easiest way to tell the difference between the two is that a crocodile has a very long, narrow, V-shaped snout, while the alligator's snout is wider and U-shaped. Because of the wide snout of the alligator it packs more crushing power to eat prey like turtles that constitute part of its diet. The narrow crocodile snout, although still very powerful, is not really suited for prey like turtles but is very versatile for fish and mammals.

Another physical difference between the crocodile and the alligator is that the crocodile's upper and lower jaws are nearly the same width, so the teeth are exposed all along the jaw line in an interlocking pattern, even when the mouth is closed. They also have an enormous 4th tooth on the lower jaw that is accommodated by depressions in the upper jaw just behind the nostrils.

An alligator, on the other hand, has a wider upper jaw, so when its mouth is closed the teeth in the lower jaw fit into sockets of the upper jaw, hidden from view. Only the teeth of the upper jaw are exposed along the lower jaw line. Even the enormous 4th tooth on the bottom jaw, which is exposed in a crocodile, is hidden in the alligator.

Another physical difference is that crocodiles have a lighter olive brown coloration, while alligators appear blackish. Alligators also prefer freshwater while crocodiles like brackish water and sometimes even ocean.

Speaking to this difference, while crocodiles and alligators both have glands on their tongues, crocodiles still use these glands to excrete excess salt. Alligators seem to have lost this ability, making their tolerance for salt water comparatively brief. Biologists believe this suggests that the crocodile is less removed from its oceanic ancestry.

Both crocodiles and alligators have dotted sensory pits along the upper and lower jaws that look almost like beard stubble. They detect slight changes in water pressure, thought to help the animals locate prey. These sensory pits were called Integumentary Sense Organs (ISOs) until they were renamed to Dermal Pressure Receptors (DPRs). While both animals have them along the jaws, the crocodile has one on every scale covering its entire body. Some researchers believe the crocodile's DPRs might be linked to detecting levels of salinity.

It is generally stated that alligators are docile compared to aggressive saltwater crocodiles, and that crocodiles grow larger. While true in general, there are exceptions to every rule among the many species. As an example, the average alligator grows to about 14 feet (4.3 meters), while crocodiles can reach 19 feet (5.8 meters) or more. That said there is one species of crocodile - the African dwarf - that barely reaches 5 feet (1.5 meters). Also, the Indian mugger crocodile has a decidedly U-shaped snout, breaking the V-shaped rule.

In terms of nesting, crocodiles lay their eggs in mud or sand nests near brackish water, while alligators make their nests out of mounds of vegetation surrounding freshwater.

In the United States crocodiles are only found around the southern tip of Florida, though they can also be found in the Caribbean, Central America and South America. Alligators are found in the southeastern United States, and South Florida is the only known place in the world where crocodiles and alligators cohabitate the same areas.

Crocodilians, which includes both crocodiles and alligators, are believed descended from archosauria which lived 250 million years ago at the end of the Paleozoic era when all the continents were joined together in a single mass known as Pangea. About 30 million years later in the Triassic period (220 million years ago) archosauria split into two lines of evolution, one being crocodilians and the other dinosaurs and birds. Scientists theorize that the Age of Reptiles, which lasted some 155 million years, ended about 65 million years ago when an asteroid struck Earth wiping out the dinosaurs. But while dinosaurs vanished crocodilians survived!

After surviving nearly unchanged for over 200 million years crocodiles and alligators were hunted to the brink of extinction between 1900 and 1967in a period as brief as a single man's life. Additionally their habitats continue to shrink. Today due to conservation efforts the American alligator is no longer on the endangered species list but many species of crocodiles remain at risk. Continued diligence is necessary if we are to preserve these incredible animals that open a door to the planet's early history and a window into an age of fantastic creatures that ruled the earth for tens of millions of years.

Answer 2

I'm starting at the nose, working my way back after a quick overview on coloration and range...

There are only two types of alligator, the American alligator and the Chinese alligator.

Including caimans and gavials, there are 21 species of crocodile, found in tropical waters worldwide.

Alligators are charcoal grey to black with yellowish bands, crocs can be anywhere from olive drab to golden khaki.

Alligators have a broad rounded snout, appear to have an overbite (teeth on the bottom jaw fit into sockets behind the teeth of the upper jaw). Alligator teeth are conical and spikelike. Alligators nostrils sit on two nasal discs.

Crocodiles have more slender, narrow snouts with bottom teeth visible (most prominently the fourth tooth from front, sometimes sticking well above the top of the upper jaw depending on species). Their teeth are dagger shaped, and they have a single nasal disc with both nostrils on it.

The inside of an alligator's mouth is an almond color, the inside of a croc's mouth is orangish.

The osteoderms (or scutes or "bumps" if you want to be completely unscientific about it.) on an alligator's back are in straight rows, and do not spill down onto it's sides. Croc's scutes are more pronounced, not as neatly ordered, and some species of crocodiles have osteoderms all the way into the belly skin.

Crocs have more webbing on their back feet than alligators.

Comparing tail scutes, picture a '55 Chevrolet and a '57 Chevrolet. The '55 is a gator, the '57 is a croc, much more pronounced tail fins.

Most, but not all crocodiles attain larger sizes than alligators.

Crocodiles are responsible for many more human fatalities than alligators (compare 25 human fatalities from gators in 50 years in Florida to 300 people a year on average from Nile Crocs in Africa.)

Answer 3

They're different species (different families, even) which have different ranges (alligators are found in the southern U.S. and the Yangtze River area of China, crocodiles are found in Africa, Asia, Australia, and North and South America), crocodiles are less specialized and can tolerate salt water, while alligators are fresh water creatures.
The most obvious difference between the two is the shape of their heads, with alligators having a more rounded snout and crocodiles having a more pointed, V-shaped snout.

Answer 4

my best advise is to look it up in wikipedia, and compare their descriptions