It is not quite Deep Blue Sea meets Lake Placid, but close; Jaws meets Alligator would have been a better comparison, had the last film been as familiar as the other three.
Alligators are largely freshwater animals while sharks inhabit the sea, so few would expect — or wish — to run into both predators in the same environment. In fact, they do encounter each other, for American alligators sometimes venture into marine ecosystems. And when that happens, the alligators feed on the sharks. And possibly vice versa, according to evidence compiled in a rare study of the interactions between the two predators.
The study, published in Southeastern Naturalist, records instances of American alligators preying on three shark species — nurse shark, bonnethead shark and lemon shark, the former two with photographs. It also describes the remains of Atlantic stingrays found in the jaws and necks of two alligators. Sharks and rays are classified together as elasmobranchs, or cartilaginous fishes; the Atlantic stingray is known to inhabit freshwater environments.
Evidence for sharks preying on American alligators is scantier. Instances of this have been reported only through eyewitness accounts published in a few newspaper and magazine articles of the late 19th century, the study notes.
Interactions between alligators and sharks have rarely been studied, the main reason being the different ecosystems they inhabit. Another reason is that the food consumed by alligators is difficult to identify from the contents of their stomachs.
“The stomach acids of alligators are very strong and can digest soft tissue very quickly,” James C Nifong, lead author of the new study, told The Indian Express by email. “As a result, remains of sharks and rays may not persist very long after being consumed, limiting the window researchers have to recover that evidence.”
Nifong, a Kansas State University zoologist, performed his PhD studies on the use of marine habitats by American alligators. His co-author is Russell H Lowers, a NASA scientist who has done previous research on alligators for the Kennedy Space Center.
The possibility that alligators may prey on sharks struck Nifong during research for his PhD. “I am also an avid fisherman, catching many small sharks and rays in the same location I was studying large alligators,” Nifong said. “I began to wonder if alligators do indeed consume sharks and rays.”
The earliest evidence of such consumption recorded in the study is from 1997, when marine turtle researcher M Frick reported instances of alligators consuming a bonnethead shark and a lemon shark in Florida, but without photographs. In 2003, a US Fish and Wildlife Society staff member photographed an alligator capturing and consuming a nurse shark in an estuarine mangrove shark. And in 2006, naturalist Judy Cooke photographed an alligator consuming a bonnethead shark in a tidal salt marsh. Large American alligators potentially consume immature bull sharks, too, to some extent, the study suggests, citing an overlap of habitats in Florida.
Between 2008 and 2011, a series of alligator-stingray interactions were recorded in estuarine habitats in Florida. One alligator was captured holding an Atlantic stingray between her jaws, before the latter got away. Two other captured alligators had stingray barbs in their jaw and neck.
For sharks preying on American alligators, the study cites a series of published eyewitness accounts in Florida. In 1877, The Fishing Gazette published accounts of an epic skirmish in a tidal inlet, where hundreds of alligators and sharks had congregated to feed on schools of fish. In the days following the clash, many carcasses of both alligators and sharks were reportedly washed ashore.
Another published account, in 1884, described a shark biting an American alligator in the thoracic region, which severed it into two, after which the shark reportedly consumed one of the halves. A third account, in 1888, described a clash in which sharks reportedly removed the forelimbs and portions of the tail of some alligators.
To return to Lake Placid, crocodiles too have been reported to have fed on sharks. The study notes that besides American alligators, five more crocodilian species — American crocodile, Morelet’s crocodile, estuarine crocodile, mugger, and Nile crocodile — frequent marine and estuarine ecosystems, and are large enough to consume sharks. The study cites published accounts of estuarine crocodiles consuming bull sharks in Australia, as well as an examination, in 1961, of the stomach contents of a Nile crocodile, which included the remains of two shark species.