How Old Are Alligators? When Did They First Appear?

Alligator Lifespan - American Alligator

Written by Katie Melynn Wood

Updated: June 15, 2022

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If you’ve spent much time in Florida, you’ve probably become familiar with the American Alligator. Whether through your own encounter or hearing about a close call that someone else had, these giant animals are both formidable and very, very old. In fact, ancient dinosaurs could have had similar experiences running from a hungry gator.

Just how old are alligators and when did they first appear? Are these animals actually dinosaurs?

Description and Size

Alligators first appeared around 65 million years ago during the Cretaceous period. While not dinosaurs, they lived at the same time as many dinosaurs. These early alligators looked very similar to the species that we know and see both in zoos and in the wild today.

There are two species of Alligators that exist today. The American Alligator, Alligator mississippiensis, lives in North America. The Chinese Alligator, Alligator sinensis, lives in Asia. Both belong to the Alligator genus, Alligatoridae family, and Crocodilia order.

American Alligators are the larger of the two species of alligators still in existence. It is common for male American Alligators to get up to 14 feet and 900 pounds. Females tend to be smaller. But they are still quite formidable. Because these animals exist in the wild, catching an especially large Alligator can cause quite a stir.

Chinese Alligators are often smaller. Their size is often around 7 feet long and around 100 pounds. Their smaller size may be due to differences in evolution, environment, and diet.

Alligators are reptiles and have scaly skin. Their scales, called scutes, protect them from their environment and help regulate the water in their bodies. By repelling water and keeping the inside of their bodies hydrated, their scutes help them live safely in their natural water environment.

Their scutes are dark brownish-green or black. This makes it hard to see alligators, a useful evolutionary tool that helps them hunt. A few alligators are all white, due to albinoism or leukism, although it is very difficult for light-colored alligators to hunt and survive in the wild. When found, these animals are taken into captivity to ensure their survival.

American alligator,Alligator mississippiensis on a white background

American alligators are significantly larger and heavier than Chinese alligators.


Alligator Scientific Classification

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Crocodilia
Family: Alligatoridae
Genus: Alligator
Species: Alligator mississippiensis and Alligator sinensis

Alligators and crocodiles both belong to the Crocodilia order. They are different families, genus, and species, however. They look very similar and people often confuse one for the other. Crocodiles tend to be larger and more aggressive than alligators. Their snouts are also longer and narrower, forming a “V” shape. Alligators, on the other hand, have broad snouts that look more like a “U.”

Young Chinese alligator basking in the sun on a rock

While this is a juvenile, adult Chinese alligators often measure 7 feet long and weigh around 100 pounds

©Andy Crocker/

Diet: What Do Alligators Eat?

Alligators are carnivores, even from a young age. When they hatch and begin to eat, young alligators take down small prey. This includes fish and insects. They also eat worms and snails. As they grow, alligators learn to hunt. The type of prey they prefer often depends on what is available. Alligators eat larger fish and animals that live in or near water, such as muskrats. In some areas, alligators keep muskrat populations from becoming too large.

Adult alligators eat larger prey, such as birds, deer, panthers, and even bears. At the top of their food chain, alligators hunt and eat any prey that they can take down.

In populated areas, alligators often eat pets such as dogs. These animals are easy prey for alligators, who are used to hunting. Humans aren’t generally seen as prey at first glance, but may quickly get onto the alligator’s radar if the animal feels threatened.

Habitat: When and Where It Lived

American Alligators live in tropical climates in North America, including parts of the United States and Mexico. While Florida is known for its alligator population, the largest numbers of these animals are actually in nearby Louisiana.

Chinese Alligators live in the Yangtze River and are on the endangered animal list. Many zoos seek to conserve their species by breeding captive Chinese Alligators and helping the public learn more about these animals and their conservation.

Alligators and their ancestors have been around since the Cretaceous period, around 65 million years ago. Remarkably, these ancient alligator species are very similar to modern alligators. American Alligators and Chinese Alligators even resemble the scaley dinosaurs that lived at the same time. Because of this, alligators fascinate scientists and researchers who want to learn more about how species evolve.

Multiple species of alligators are extinct. They were all part of the Alligator genus and evolved very slowly over millions of years from the early forms of alligators.

Threats and Predators

Alligators are at or near the top of their food chain. The main threat to alligators is the change in their natural habitat and hunting by humans for food and goods.

Alligator meat is not a staple in the diet of people who live in their areas, but it is enough to make hunting and raising alligators common. Alligator skin is also used in everything from handbags to belts. American Alligators are not endangered. They were placed on the endangered species in the late 1960s. Since then, their population has recovered.

Tourism and awareness helped increase the number of alligators in the wild. Companies take tourists on tours to see American Alligators in their natural habitat.

Unfortunately, Chinese Alligators are extremely endangered. Due to the lessening of their habitat and food sources, these animals have a difficult time surviving. Zoos and conservation efforts work to make sure that they do not go extinct.

Female alligators lay eggs, which hatch into young, juvenile alligators. This is the time in their lives that alligators are most vulnerable to wild predators. Raccoons, bobcats, and even other alligators can make an easy meal of these small alligators. Mother alligators protect their young for up to two years after they hatch. When alligators attack people, it is often because they feel their territory or young are threatened.

Alligator hatching

Alligator hatchlings are frequently consumed by mammals such as raccoons.

©Heiko Kiera/

Discoveries and Fossils: Where It Was Found

The two species of alligators still in existence teach scientists a lot about how these animals evolved. Extinct species of alligators include A. hailensis, which was discovered in Haile, Florida. Scientists also found fossilized droppings of these alligators that showed they ate fish, similar to modern alligators.

Scientists also discovered alligator fossils and skeletons in the American Midwest. While far away from the natural habitat of modern alligators, during prehistoric times these regions were suitable for alligators.

The earliest known species within the Alligator genus is the now-extinct A. prenasalis. Fossils dating to the late Eocene epoch, around 33.9 million years ago, were discovered in rock formations in South Dakota. A complete skeleton of an A. prenasalis is on display in the American Museum of Natural History in New York City.

Researchers are still working to understand whether other species of alligators evolved alongside modern American Alligators and Chinese Alligators or if they branched off. Fossils can help them see how significant the changes were between species. Technology helps identify when they may have occurred.

Extinction: When Did It Die Out?

Two species of alligators, Alligator mississippiensis and Alligator sinensis, are still around today. American Alligators, A. mississippiensis, are plentiful and a well-known animal in their native North America. This was not always the case, however.

Before they were placed on the endangered species list in 1967, American Alligators were rapidly approaching extinction. People hunted them for their hides. Conservation efforts, education, and hunting regulation helped these animals make a comeback. Now, responsible alligator farming meets the demand for meat and hides without endangering the species.

Chinese Alligators, A. sinensis, are extremely endangered and more common in zoos than in the wild. Changes in their environment led to their low population. Pollution and pesticides also impact the ability of eggs and juveniles to survive to adulthood.

There are six species of extinct alligators. These include A. hailensis, A. prenasalis, A. mcgrewi, A. mefferdi, A. olseni, and A. thomsoni. Fossils and skeletons of all six have been found in North America.

Similar Animals to the Alligator

Other reptiles similar to alligators include:

  • Crocodile: These aggressive animals are often mistaken for alligators (and vice versa). Crocodiles can get larger and have a pointier snout. In North America, they are only found on the Southern tip of Florida, while alligators can be found along the coast of the South and even in Texas.
  • Caiman: Caiman or Cayman are also members of the Alligatoridae family. They are native to South and Central America. They are often smaller but can get up to 14 feet, similar to an American Alligator.

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About the Author

Katie is a freelance writer and teaching artist specializing in home, lifestyle, and family topics. Her work has appeared in At Ease Magazine, PEOPLE, and The Spruce, among others. When she is not writing, Katie teaches creative writing with the Apex Arts Magnet Program in Anne Arundel County, Maryland. You can follow Katie @katiemelynnwriter.

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