To a squirrel, this is the best time of the year. Not only are they eating with reckless abandon to fatten up for winter, they're finding food and hiding it. But how do squirrels know how many nuts to store? And when to get started?
"The honest answer is we don't absolutely know," said David Stephens, Ph.D., a professor of animal behavior at the University of Minnesota.
"We know that all animals have internal clocks," he explained. "They know that as the days begin to shorten, and I say 'know' kind of in quotes there, that fall is approaching."
Squirrels don't generally hibernate so they need to eat during the winter. But there's not a lot of food around. That's not the case during the fall, when seeds fall from the trees, providing ample food.
So do squirrels have a target number of seeds they need to store for the winter?
"We think it's primarily determined by availability," said Stephens. In effect: "they run into something, a little supply of food, and they say, 'Gosh I'm gonna put this away.'"
How do squirrels make sure other animals don't steal their stored food?
"Of course other animals do steal their stuff. But what's cool is that they actually are sensitive to this, these are called audience effects of caching," said Stephens.
Some research indicates that squirrels will act in a more sneaky manner when they believe another animal is watching, by hiding the seeds and nuts in a more scattered manner.
So how do squirrels know where to find the buried food? Do they remember?
"They seem to encode information about landmarks ... He may know that tree over there is a place where I cached one. They are able, pretty much, to recover things that they've hidden based on some kind of memory," explained Stephens.
Of course, they don't remember everything. Some researchers believe that squirrels find about 50 percent of what they bury. Typically those seeds are buried about 0.5 to 2 inches beneath the soil surface, so forgotten seeds often sprout into new trees.
Check it out Squirrel Behavior.