There are hundreds of species of reptiles in North America. Reptiles are adaptable, but they thrive in warmer climates. They are found throughout almost all North America except the far northern regions of Canada and Alaska.
Reptiles are a very diverse group. They include snakes, turtles, crocodiles, and more. Whether you measure in length or weight, there’s no denying that some reptiles here surpass the rest.
Although four of the reptiles on this list are not native to North America, they are probably here to stay and are impressive creatures.
We will count down the ten most giant reptiles in North America based on several factors. Read on to learn about the enormous reptiles in North America!
10. Bolson Tortoise
The Bolson tortoise is the largest in North America. Their shells can reach almost two feet and weigh nearly 40 pounds. They are critically endangered, and their numbers continue to decline.
The range of a Bolson tortoise is currently restricted to a small area of northern Mexico. They primarily eat grass and shrubs. Efforts are underway to establish captive breeding programs with future reintroducing individuals to their former range.
9. Eastern Indigo Snake
The eastern indigo snake is the longest snake native to the United States. They can reach nearly 8 feet long as adults. The habitat of eastern indigo snakes is restricted to Florida and southern areas of Georgia, Alabama, and Mississippi.
They are often observed sharing burrows with gopher tortoises in pine-oak sandhills. During the summer, they can often be seen on the edges of wetlands.
Eastern indigo snakes regularly feed on mammals, birds, and frogs. They have even been known to eat other snakes, including rattlesnakes and cottonmouths. It is believed that they are immune to the venom of these snakes. The eastern indigo snake is a federally threatened species due to habitat loss.
8. Eastern Diamondback Rattlesnake
The Eastern diamondback rattlesnake is the giant venomous snake in North America. They can reach 8 feet long and weigh up to 10 pounds.
These snakes are pit vipers, meaning they have visible sensory pits on their heads, which they can use to detect heat emitted by their prey. They generally live in the dry, pine flat woods, sandy woodlands, and coastal scrub habitats from southern North Carolina to Florida and west to Louisiana.
An Eastern diamondback rattlesnake diet comprises rats, mice, squirrels, and birds. They can accurately strike distances up to a third of their body length. This means an eight-foot snake can accurately bite something nearly three feet away.
Though they are feared as deadly and aggressive, eastern diamondback rattlesnakes are highly averse to human contact and only attack for defense. Most bites occur when humans taunt or try to capture or kill a rattlesnake. A taste from an eastern diamondback rattlesnake is excruciating and can be fatal to humans. However, edges can be treated with antivenom, rarely resulting in death.
7. Nile Monitor Lizard
The Nile monitor lizard is the biggest in North America. Nile monitors can grow up to 7 feet long and weigh nearly 20 pounds. They were believed to be introduced to North America as part of the pet trade in the 1990s.
These lizards wander over large areas, increasing and breeding at an early age, laying up to 60 eggs at a time. Nile monitor lizards now number in the thousands in North America, with several breeding populations in Florida.
They feed on fish, snails, frogs, snakes, birds, small mammals, insects, and carrion. They also feed on alligator and crocodile eggs and young. This raises the concern that they can decimate populations of native wildlife in Florida. However, their population has not yet grown enough to cause significant damage.
The Nile Monitor is an impressive reptile and the giant lizard in the world.
6. Spectacled Caiman
The caiman is small compared to many other crocodilians, but it is still a giant reptile. They can grow to over 8 feet long and weigh over 100 pounds.
They are native to southern Mexico and regions of South America. However, in the United States, spectacled caimans have been introduced to Florida through intentionally released or escaped pets. There are now several established breeding populations in Florida.
Spectacled caimans are highly adaptable; they prey on any animals they can get. Smaller caimans tend to feed on snails and insects, while larger ones will regularly eat crabs and mammals.
5. Alligator Snapping Turtle
The Alligator snapping turtle is the giant freshwater turtle in North America. Males have been known to grow to 250 pounds and live to be 100 years old. They have massive heads and jaws with a bite force of 1,000 pounds.
They live almost exclusively in the rivers, canals, and lakes of the southeastern United States. Their tongues have a unique pink lure, which they use to bait fish into swimming into their mouths.
Adult alligator snapping turtles have no natural predators. However, their numbers have severely reduced due to the pressures of hunting and the pet trade. They are now protected throughout most of their range.
4. African Rock Python
The African rock python regularly grows over 11 feet long. Although they now have established populations in south Florida, African rock pythons are native to south and western Africa.
These snakes are among the most aggressive reptiles. They were believed to be introduced by pet owners who released snakes that they could no longer handle.
African rock pythons have a voracious appetite. They will prey on small antelope, warthogs, dogs, monkeys, goats, and crocodiles in their natural range in Africa. In North America, they will prey on alligators, deer, and other mammals. These pythons are believed to be only established in a small area near Miami, Florida. Hopefully, these giant reptiles do not spread much further.
3. Burmese Python
Burmese pythons are giant snakes. They can grow to 23 feet and 200 pounds. Although they are not native to North America, they have been introduced to the Everglades like many others on this list.
Scientists believe that the snakes in the Everglades either escaped or were intentionally released from the pet trade. They pose a significant threat to native wildlife.
Burmese pythons, including birds, mammals, and even alligators, eat anything they can overpower. These massive snakes have been established in North America since the 1990s.
2. American Crocodile
The American crocodile is a massive reptile. Males can grow to over 14 feet and nearly 1,000 pounds. The populations in central and South America feature even bigger individuals but animals of that size have not been recorded in North America.
A crocodile will eat almost anything that moves. Hatchlings and young crocodiles eat small fish, snails, crustaceans, and insects, while adults feed primarily at night on fish, crabs, turtles, snakes, and small mammals.
They thrive in brackish or saltwater areas. Their habitat is the fresh or salty water of river estuaries, coastal lagoons, and mangrove swamps.
In the Florida Everglades, their range overlaps with American alligators. This is the only place where alligators and crocodiles live together.
They can be distinguished from American alligators based on their longer pointed snouts. American alligators have rounder, shorter bills. Illegal hunting and habitat depletion have reduced their numbers. American crocodiles are considered a vulnerable species, but their numbers are rising.
1. American Alligator
American alligators are giant reptiles in North America. They can grow to impressive sizes. An adult male American Alligator can easily reach 15 feet long and weigh 1,000 pounds. The giant Alligator ever recorded was said to be 17 feet 5 inches long.
Alligators are carnivorous opportunists. They will eat anything that they are big enough to overpower. Their diet consists of fish, amphibians, birds, mammals, and crustaceans. In rare cases, American alligators have been known to eat humans. In areas where American alligators are common, people are advised to stay away from the water’s edge.
They live in the wetlands of the southeastern United States. The largest American alligator population is in Gainesville, Florida, where they live in freshwater rivers, lakes, swamps, and marshes.
American alligators were placed on the endangered species list in 1967. Since then, the population has rebounded, with over 1 million American alligators alive today. As the population grows, we may soon see an alligator that breaks the current 17-foot 5-inch record.
North America has some genuinely unique reptiles. These modern-day monsters can grow to incredible sizes. With the American Alligator at number one on the list at 17 feet and 1,000 pounds, North America has the ecosystems to allow reptiles to flourish.
The next time you are outdoors, look for a reptile. They can be harder to spot than other animals due to their secretive nature and silent ways, but you might spot one of the giant reptiles on this list!
Bryan Harding is a member of the American Society of Mammalogists and a member of the American Birding Association. Bryan is especially fond of mammals and has studied and worked with them around the world. Bryan serves as owner, writer, and publisher of North American Nature.