Alligators are freshwater crocodilians, native to southern North America and to China. With just two species, they’re also relatively rare.
In fact, the Chinese Alligator is so endangered in the wild that there are more living species in zoos.
In the United States, that’s another story. With a population of over 5 million North American Alligators in the wild, they’re listed as “of Least Concern”.
Alligators, much like crocodiles, are long, flat, and feature elongated mouths. Most are also opportunistic predators, resting in wetlands and feeding on aquatic mammals, fish, and birds.
And, like other crocodilian (crocodile-shaped) animals, they have a dense green or brown outer hide that serves to protect them from predators.
Like all crocodilians, they have non-overlapping scales, called “scutes”. These are arranged in regular rows and patterns. They’re also made of keratin, allowing the alligator to grow them like fingernails.
But, alligators aren’t unique. In fact, they’re just one of 7 different types of crocodilians.
Scientific name (genus): Crocodylus
Summary: Crocodiles share almost everything but snout shape with Alligators, although they also prefer saltier water than their cousin.
Crocodiles, also known as “True Crocodiles,” are the most diverse group of crocodilians. With 13-14 living species distributed across the Americas, Asia, Australia, and India, true crocodiles are everywhere.
However, true crocodiles only live alongside alligators in Florida. Elsewhere, the two species keep their distance – largely because crocodiles prefer saltwater or brackish water (acidic and salty fresh water).
Differences don’t’ stop there. For example, crocodiles are normally larger. However, that significantly depends on the species.
If you look at the American Crocodile, crocodiles are normally about 30% heavier (800-1000 lbs. for a male crocodile versus about 700 for a male alligator).
Crocodiles also lack the characteristic black spotting often seen on alligators. However, not all alligators feature those spots.
Otherwise, both animals look and sound very similar. In fact, both also eat very similar diets, and have almost identical physiological makeup and appearance.
2. Dwarf Crocodiles
Scientific name (genus): Osteolaemus
Summary: Dwarf crocodiles look exactly like true crocodiles but at an average of 1/10th of the size.
Dwarf crocodiles are a small genus of crocodilians closely related to the true crocodile. As the name suggests, they’re also very small compared to the true crocodiles.
Both living species in the genus reach a maximum length of about 6 feet. In addition, females rarely top 80 lbs. and males rarely top 180 lbs.
That’s a large difference from the true crocodile, where the largest specimens have been recorded at 23 feet and over 2,200 pounds. Of course, in both true and dwarf crocodiles, “average” sizes are much smaller.
Both species of dwarf crocodile are also native to the African continent. However, one is only found in the Congo.
Otherwise, there’s not much to differentiate the Dwarf crocodile from other crocodilians. However, some populations are known to develop orange and red pigment when living in caves – although we don’t know why.
Scientific name (subfamily): Caimaninae
Summary: Caimans are the closest living relatives of alligators, and you may be hard-pressed to tell the two apart – except for size.
Caimans are a group of small crocodilians in the Alligatoridae family. Today, there are 9 living species of caimans, ranging from the broad-snouted caiman to the dwarf caiman.
Caimans are unique in that they are the only other animal in the Alligatoridae family. However, with significant genetic distance between them and alligators, many are genetically closer to crocodiles.
However, some like the broad-snouted caiman are difficult to tell from small alligators. Caimans are also shorter but heavier than alligators.
For example, most caimans don’t exceed about 10 feet in length. Most also weigh an average of about 13-88 lbs.
However, the black caiman can exceed 16 feet and weigh over 2,000 lbs. On average, black caimans will be about a quarter of that size.
Cuver’s Dwarf Caiman averages under 5 feet. In addition, it normally weighs about 15 lbs. That makes it the smallest of all crocodilians.
In addition, all caiman species are native to South America, with many based around the Amazon Basin. Like alligators, they also prefer fresh water, and can normally be found in large and slow-moving rivers.
Scientific name: Gavialus gangeticus
Summary: Gharials resemble alligators at first glance but at second glance, have a much longer, thinner snout than their cousins.
Gharials, sometimes known as “fish-eating crocodiles” are a crocodilian native to the Indian subcontinent.
Gharials look very similar to alligators. However, with a long, thin snout, gharials are unable to exert the biting force of a crocodile or alligator.
This means they are unable to bite off and chew food, which almost entirely restricts their diet to fish. That suits the gharial well, because it’s almost entirely aquatic.
Most spend all of their time in the water, avoiding preying on carrion or small mammals like most other crocodilians.
Gharials also stand out as being one of the longest crocodilians compared to weight. For example, records show that males can reach lengths of over 30 feet and weigh over 2,000 lbs. Most gharials are significantly smaller, averaging about 8-15 feet.
5. False Gharial
Scientific name: Tomistoma sclegelii
Summary: With a slender snout and reddish mottling, false gharials look less like alligators than many other species on this list, but you’d still be hard-pressed to tell the difference at a distance.
The false gharial is a crocodilian that closely resembles the alligator.
Unlike the true gharial, it also features a shorter snout (although longer than an alligator). However, it still has one of the slimmest snouts of any crocodilian, with only the true gharial beating it.
In addition, most are relatively small. The longest recorded male was just 15 feet, with most not weighing more than 450 lbs. H
owever, they are among the most colorful crocodilians with patterns of reddish brown and black or white mottling.
All false gharials are native to Malaysia, Sarawak, and Indonesia. While not native, there are also populations in Vietnam, Thailand, and Singapore. And, with a presence in swamps and in rivers, false gharials are very diverse.
False gharials also differ from gharials in that they attack and eat almost anything they can. As a result, their diet ranges from monkeys to fish to insects and even deer.
6. Slender-Snouted Crocodiles
Scientific name (genus): Mecistops
Summary: Slender-snouted crocodiles look similar to alligators but with an elongated, V-shaped snout and more mottling across the back and shoulders.
Slender-snouted crocodiles include two species of medium-size crocodilians native to sub-Saharan Africa. The genus used to be included in true crocodiles but was moved because it is genetically different.
Both species of slender-snouted crocodiles average about four feet and 350 lbs. as adults. However, older specimens can be as long as 14 feet and can weigh as much as 700+ lbs.
As the name suggests, they’re also characterized by a slender snout, which is long and tapered, creating a “V” shape.
Slender-snouted crocodiles also have one of the longest egg incubation periods of any crocodilian, with over 100 days needed to hatch eggs. In addition, the eggs’ sex is based on the temperature during the first three weeks of incubation.
Crocodilians are one of the oldest living types of animals. So, it makes sense that there are a lot of them. In fact, Deinosuchus is an 82 million-year-old fossil of a giant crocodile, which was probably 30-40 feet in length.
Today’s crocodilians are normally shorter. However, many of them still look exactly as they did millions of years ago.