Even crocodiles need their five a day, it seems. At least half of all species of alligator and crocodile supplement their meaty diet with the flesh of fruit.
Reports that crocodiles have a taste for fruit go back decades, says Thomas Rainwater at the US Fish and Wildlife Service in Charleston, South Carolina. “But since these animals were long considered carnivores, no one paid much attention.”
In a routine analysis of American alligators (Alligator mississippiensis) living in the Everglades National Park in Florida, Rainwater and his colleagues found fruit including pond apples in the alligators’ stomachs. They then turned up reports that at least 13 of the 23 living crocodilian species are fruit eaters.
Whether or not crocodilians actively go after fruit is debatable – especially as the predators are secretive and tend to do most of their foraging at night. A crocodile might simply eat an animal that has itself recently dined on fruit, for example.
But there is some evidence that fruit is consumed deliberately, too. Last year a researcher working in south-east Asia reported seeing a wild Siamese crocodile tucking into a watermelon. Perhaps, like grinding stones in a bird’s crop, the heavy seeds of some fruits may help the animals digest their meatier meals.
Crocodilians roam and swim over large areas, so could they be important seed dispersal agents? “As far as we can tell, there are no plants that rely exclusively on crocodilians as dispersal agents,” says Rainwater. Indeed, saurochory – the act of seed dispersal by reptiles – has largely been ignored by researchers, he says. “But given the number of seeds we have found in some stomachs, we suspect they may be important for some wetland species.”
Carlos Herrera at the Doñana Biological Station in Seville, Spain, who has studied fruit-eating in carnivorous mammals, says the results make sense. “Whenever sufficient attention is paid, nearly all vertebrates are found to ingest seeds of fleshy-fruited plants at one time or another, either deliberately or accidentally,” he says.
Journal reference: Journal of Zoology, doi.org/m9x