In a week that has already revealed an extinct giant dinosaur-eating frog, scientists have confirmed that alligators’ diets are much more interesting than we thought. It turns out the animals are not averse to dining out on a spot of shark.
The study, carried out by James Nifong of Kansas State University, looked at the many undocumented cases of American alligators (Alligator mississippiensis) eating other top predators like sharks and stingrays, and even the sharks’ reciprocal predation. It’s basically a scientific paper on alligators vs. sharks. Thanks to the journal Southeastern Naturalist for publishing it.
(This is also a SyFy movie waiting to happen. Oh wait, no, it kind of already exists.)
Nifong points out in his study that the eating habits of American alligators, which are freshwater inhabitants, are well-documented. However, due to the number of sharks he encountered while studying gators in a marine habitat, he decided to find out whether the two predators had a history together.
He thought it quite likely. “Alligators are opportunistic,” he told New Scientist. “They’re not going to pass up a big chunk of protein that’s swimming by.”
By going through the literature, Nifong discovered a few cases of alligators eating elasmobranchs – the group of cartilaginous creatures that includes sharks, rays, and skates.
He found evidence of an alligator predating a lemon shark, a nurse shark, a bonnethead shark, and a stingray. He thought the evidence was so scant because alligators have notoriously acidic stomachs, capable of dissolving the cartilage of these creatures without leaving any trace.
He also, however, found evidence that the sharks were biting back.
Nifong found plenty of evidence that sharks definitely predate on crocodiles, mainly in Colombia, where great whites prey on American crocodiles, and Australia, where tiger sharks gobble up saltwater crocs. Evidence for alligators was vaguer.
However, it appears that sharks and crocodilians in all forms have a history that goes way back.
A 2015 study revealed prehistoric crocodilians with bite marks from sharks in the late Cretaceous period. More recently – well, 1877 – The Fishing Gazette reported an incident titled “Alligator and Shark Fight”, where fish trapped by a high tide in Florida attracted hundreds of sharks and alligators who “fought like dogs” over the meal. According to the article, for days after the battle, carcasses of both species littered the beaches of Florida, up to 80 miles away.
Nifong concludes that both animals are opportunistic predators with extreme eating habits, and neither would miss an opportunity to feed on the other if the situation presented itself.
He hopes to bring attention to the predator vs. predator conflict as both groups contain species on the IUCN red list. Numbers of both are much smaller today, which may explain why we haven't seen a bigger clash between the two top predators that occasionally inhabit the same space.