Researchers from Kansas State University have found that American alligators are hunting sharks that venture out into freshwater, according to a new study published in Southeastern Naturalist. The team made this discovery by analyzing the stomach contents of 500 living alligators. They found that the reptiles had feasted on four different shark species, including both nurse sharks and stingrays.
This discovery is interesting because alligators swim in freshwater, while sharks and their relatives live in saltwater. However, as the stomach contents reveal, there are times where the two predators overlap.
Though alligators do not have the glands needed to properly filter saltwater, they have been known to travel into oceanic regions to hunt when salt levels become diluted after events like heavy rainfall. In addition, scientists have noted many instances where sharks have moved into rivers and deltas.
“Alligators seek out freshwater in high-salinity environments,” explained lead author James Nifong, a researcher at Kansas State University, according to Newsweek. “When it rains really hard, they can actually sip fresh water off the surface of the saltwater. That can prolong the time they can stay in a saltwater environment.”
Despite the results of the study, the team states that alligators do not always win battles with sharks. Rather, the team believes the two species engage in what is known as “reciprocal predation,” where they hunt each other at different times. Then, body size typically determines if the alligator or shark comes out with a meal.
The study shows the shift in certain ecosystems and could help researchers better understand the dynamics that come about as alligators and sharks move closer to each other.