Usually pushups are meant for a workout, but for Little Scrub Island ground lizards, it's more like ringing the dinner bell. Scientists behind a new study found that when ground lizards perform pushups near extra food, they are essentially inviting their neighbors over to dig it.
What's unusual about these reptiles is that they seem to be more willing to share compared to other lizards - most lizard species are territorial or, like the fig-eating cape flat lizards, attempt to steal food from one another.
But researchers from Erell Institute in Lawrence in Kansas found that Little Scrub Island ground lizards (Ameiva corax) are highly social eaters.
The findings were published in the journal Behavioral Ecology.
They spent eight days on Little Scrub Island, a tiny isle in the Caribbean, observing these animals. The research team presented the reptiles with three objects, to see when lizards choose to invite friends over: a whole prickly pear, split down the middle; a quarter of a pear; and a red Swiss Army knife, which the scientists say was roughly the same size and color of a pear.
When the lizards encountered the whole pear, scientists were surprised by what they saw. They would perform a quick pump of their legs as a way of communicating nonverbally in noisy environments.
What's more, ground lizards performed the act at a more rapid rate when surrounded by plenty of food. But as more hungry diners showed up and the meal lessened in size, the legs pumps gradually subsided.
However, ground lizards aren't always so giving. If the reptiles discovered a quarter of a fruit, he or she was much more likely to hunker down in a display of aggression than perform an invitational pushup.
The authors believe that these unusual displays are due to the lizards' diet. Their favorite foods are considerably large, making it difficult to eat for just one person. By calling over more mouths, it's a bit easier to eat large fruit like a prickly pear.
"The diet of the lizard Ameiva corax includes bird eggs and fruit," the authors wrote, "which are items that represent more food than a single individual typically consumes."
[Credit: Thu-Ha Trinh]