Alligators vs. Crocodiles: See the Difference in Taxonomy, Physical Appearance, Habitat

Alligators and crocodiles almost look the same that many people do not know their differences and confuse them from one another. Despite sharing a number of similarities, each of them has its unique characteristics.

Here are some facts and easy ways to tell whether it is an alligator or a crocodile.

Taxonomy

According to the journal Pathology of Wildlife and Zoo Animals, all alligators and crocodiles belong to the taxonomic order Crocodylia. Under that, there are three major families, namely the Alligatoridae or alligators, Crocodylidea or crocodiles, and Gavialidae or gharials.

All three families under the taxonomic order Crocodylia share a common evolutionary ancestor. However, the New York Times reported that Alligatoridae and Crocodylidae diverted around 80 million years ago during the Late Cretaceous period and since then continued their own evolutionary journey.

For millions of years, alligators and crocodiles have remained relatively similar in physical appearance but also sport some surprising differences that are easily detected.

ALSO READ: Study Reveals Alligators Can Also Regrow Their Tails

Physical Appearance

Alligators and crocodiles look similar at first glance, but a closer inspection would reveal that they have different snouts. According to Live Science, their snouts are one quick-fire way to distinguish a crocodile from an alligator.

Looking at their jawline, alligators have an overbite, so the bottom jaw fits into the sockets in the top jawline and conceals them. Meanwhile, the book Biology and Evolution of Crocodylians says that the bottom teeth of a crocodile sit on the outside of the mouth and slot into grooves along its top jaw.

Moreover, alligators have a U-shaped rounded, wide, and short snout compared to crocodiles that have longer and pointed snouts that form a V shape. However, there is an exception to this rule, like the mugger crocodile (Crocodylus palustris), which has a rounded snout like an alligator.

Both alligators and crocodiles have integumentary sense organs (ISOs) or the tiny black specks on their heads that allow them to detect pressure changes in the water caused by potential prey. According to the Journal of Experimental Biology, these sensory organs are found on the head and around the mouths of alligators, while crocodiles have them on almost every scale of their body.

But more than their skin, a 2018 study, titled "Comparative Limb Proportions Reveal Differential Locomotor Morphofunctions of Alligatoroids and Crocodyloids" published in the journal Royal Society Open Science, reveal that alligators have shorter humerus bone in the forelimbs and shorter femurs in their hindlimbs.

Habitat

The last difference between alligators and crocodiles is their habitat. According to the Journal of Comparative Physiology, crocodiles have lingual salt glands on their tongues that allow them to expel excess salt from their bodies and enable them to live in salty marine environments, like Australia's saltwater crocodile (Crocodylus porosus) that live in mangroves, swamps, and deltas.

Despite having similar salt glands, alligators' gland is not as effective as crocodiles and limits their tolerance for saltwater. Therefore, they mainly live in freshwater habitats, like lakes and marshes.

An article in National Geographic shared that the reptiles' tolerance to saltwater explains their global distribution, wherein crocodiles are usually found across the Americas, Africa, Asia, and Australia. Meanwhile, alligators are predominantly found in North and South America.