Alligator Vs Crocodile: Who Would Really Win in a Fight?

Alligators and crocodiles are descended from ancient ancestors that lived alongside the dinosaurs. Their last common ancestor lived between 90 and 100 million years ago, and since then both creatures have developed extreme physical attributes that make them apex predators in their own habitats.

But which is the mightier of the two?

The Key Physical Differences

alligator and crocodile
An alligator in Florida (left) and a saltwater crocodile (right). One of the key physical differences between the two is the shape of their heads. Getty Images

There are two living species of alligator—the American alligator and the Chinese alligator. The former is the larger of the two, with male American gators reaching up to 15 feet in length and weighing up to 1,000 pounds. Male Chinese alligators grow to about 5ft and weigh up to around 85lbs.

Crocodiles are more diverse, with 14 different species. The largest of these is the saltwater crocodile, which can reach 23 feet and weigh 2,200lbs. Nile crocodiles and American crocodiles can grow to around 20ft.

Frank T. Burbrink, the curator-in-charge at the Department of Herpetology at the American Museum of Natural History, told Newsweek the easiest way to tell the difference between a crocodile and an alligator is from their head shape.

"Alligators generally have a wider head (u shapes) than crocs (v shaped) and when alligators close their mouths you can only see the top teeth," he said.

"In contrast, crocs have a narrower snout and their lower teeth are visible when their mouths are closed. Also, alligators tend to have shorter humerus and femur bones."

Adam Rosenblatt, from the University of North Florida, told Newsweek: "The head shape is the biggest morphological difference. Also, crocodiles tend to have lighter colored skin, while alligators tend to have darker colored skin."

Wolfgang Wüster, reader in Zoology at Bangor University in the U.K., also pointed to the differences in their snouts: "Basically, if you can see a lower jaw tooth sticking up outside the mouth, it's a croc," he told Newsweek.

Which Can Run Faster?

A saltwater crocodile, the fastest of all the crocodiles, swims at speeds of between 15 and 18 mph. American alligators are faster, clocking speeds of up to 20mph in the water.

Both are, however, far slower on land. Their bodies aren't made for endurance running, so while they are extremely fast for short bursts, they can't sustain that pace. One saltwater crocodile was recorded moving at 12 meters per second. That equates to almost 27 mph. But that was for just a quarter of a second.

On land, saltwater crocodiles can run for a longer amount of time at around eight to nine mph. American alligators can move at a similar speed, able to run at 7.5 to 9 mph for short distances.

The average human can sprint at speeds of between 12 and 18 mph for short bursts. The fastest human ever recorded, Usain Bolt, can run at 27 mph. So on land, the average human could probably outrun an alligator or crocodile, so long as they are not within the alligator or crocodile's striking distance.

Running in zigzags is often given as advice if a crocodile or alligator is pursuing you. But, in an article about living with alligators, experts at the University of Florida said that is a myth: "This is a common misconception. First, it is rare for an alligator to pursue a human because humans are too large to be suitable prey. However, if an alligator does make an aggressive charge, run fast and straight (away from the alligator, of course). They usually do not run very far. But remember they are most likely to charge at you if you are near their nest."

Western Australia's Department of Parks and Wildlife also dispels this, saying: "Run as fast as you can in a straight line as crocodiles can only manage short bursts of speed when coming out of the water but cannot sustain this for long."

Which Is More Dangerous?

"Crocs are probably more dangerous, but a lot of what makes something perceived to be more dangerous is the density of humans occupying their habitats and thus frequency of negative encounters between humans and crocs or alligators," Burbrink said.

Alligator attacks account for about one fatality a year in the U.S., and make up around 6 percent of attacks on humans by all crocodilian creatures globally. They tend to take place when a person is swimming or wading at the water's edge. The University of Florida says that while unprovoked alligator attacks do happen, they are generally preventable and the fatality rate is low. About 4 percent of attacks in the U.S. are fatal, with most encounters resulting in a bite and immediate release.

Nile crocodile
A file photo of a Nile crocodile. This species is thought to be responsible for the most human deaths of all the crocodilian species. Getty Images

Saltwater and Nile crocodiles are responsible for far more human deaths than alligators. "All crocodilian species can be dangerous, but crocodiles hurt people most frequently," Rosenblatt said.

Of these two species, Nile crocodiles are the deadlier. CrocBITE, the worldwide crocodilian attack database, says many fatal attacks by Nile crocodiles go unreported. Very rough estimates put fatalities in the hundreds. In comparison, the CrocBite website shows 20 fatal attacks by saltwater crocodiles so far in 2020.

"Nile and saltwater crocodiles have a long track record of eating people, so globally, those two stand out as by far the most dangerous crocodiles," Wüster said. "In the Americas, neither American crocs nor Mississippi alligators habitually attack people, so there is not much to choose there."

Marisa Tellez, co-founder of the Crocodile Research Coalition, said the area and population is important in assessing danger. She said the alligators in Louisiana and Florida are "definitely more bold" than those found in Belize.

"But the Indo-Pacific crocodile in Australia as well as the Cuban crocodile is known to be overall aggressive towards people," she told Newsweek. "Then you have Nile crocodiles where in some areas they are considered dangerous, then other areas in Africa people are swimming with them."

Which Would Win in a Fight?

If the biggest alligator in the world fought the biggest crocodile in the world, the outcome would likely go in the crocodile's favor, Rosenblatt said.

"The biggest crocodiles in the world are larger than the biggest alligators," he said. "Saltwater crocs can get to almost 21ft long while alligators only get to almost 15ft long. So if the largest gator fought the largest croc, the croc would probably win."

Tellez said: "The largest crocodile species in the world is the Indo-Pacific crocodile [also known as the saltwater crocodile] (Crocodylus porosus) which is known to be one of the most aggressive and likely would be able to easily take down the largest alligator."

saltwater crocodile
A file photo of a 16ft saltwater crocodile. In a fight with an American alligator, the crocodile would probably win because of its size advantage. Getty Images