July 13, 2007 — Giving a squirrel a big, sweet cookie can be a kind gesture, and now scientists have found it also encourages the critter to watch for predators. The conclusion, in a newly published study, has implications for other species, including the survival of those facing human-caused changes to their habitats.
Most animals have two daily concerns: Getting food and not becoming food. Unfortunately, concentrating on one of those activities is almost always at the cost of the other.
"These two things make you survive," said animal behavior researcher Joanna Makowska at the University of British Columbia and lead author of a paper on an experiment that revealed how squirrels juggle those needs in the July issue of Animal Behaviour.
"Most animals can’t be very vigilant while eating," Makowska told Discovery News.
To get a clearer picture of just how and when squirrels choose to focus on food or predators, she and her undergraduate professor at McGill University, Donald Kramer, created an experiment that put the squirrels to the test. They placed sunflower seeds inside a two-and-a-half-foot high frame that blocked their peripheral views of the urban park in which they lived.
The idea was to force the squirrels to choose between eating and hopping out of the frame to watch for dogs, foxes and other predators.
"The squirrels never left," said Makowska. "They just ate them all. We thought this was strange."
So Makowska suggested they try giving the squirrels something that took more than a few seconds to eat, like soda crackers with peanut butter, which takes about three minutes for a squirrel to finish off.
"Lo and behold: When they ate the peanut butter crackers they moved out of the frame," said Makowska. "That confirmed to us that they valued being vigilant" even when they were eating, when the food makes it possible.
"By setting up this little test, we got them to tell us ‘Is the view important while you’re eating?’" said Kramer. "With a big food item it seems like it’s worth it to re-position."
The matter is important beyond squirrels because so many animals have to make the same choice in one way or another. And, as habitats change, their choices may or may not help them survive, explained animal behavior researcher Peter Bednekoff of Eastern Michigan University.
