The squirrel’s provisions: how does he know where his nuts are hidden?


Of all the mammals which constitute food stocks for the winter, the squirrel is the king of the hiding place: at the end of the summer, it begins to bury its provisions in various places located on its home range. Months later, the squirrel is able to find almost all of the thousands seeds and nuts that he has hidden. But how does he do it?

Why does the squirrel stock up?

While some animal species migrate to warmer areas where food is abundant, others hibernate after having stored enough fat to spend the winter. A third category of animals does not come into lethargy during the cold season and must imperatively feed for to survive. It is undoubtedly in mammals that we find the most food-saving species. So ermines, mouse, weasels, muskrats, beavers and foxes also make winter provisions, the squirrel is by far the most amazing in the amount of food collected and in the art of finding them.

What kind of food is the squirrel hiding?

As seen previously, unlike some animals such as marmots or the hedgehogs, the squirrel do not hibernate and must therefore build up reserves to sustain themselves in winter when food becomes scarce. In coniferous forests, for example, this vital storage begins at the end of thesummer : the rodent then sets aside seeds conifers, Scots pines, spruces or aroles. He also buries others fruits trees (acorns, beechnuts, nuts, cones …) as well as mushrooms dried beforehand. As to Hazelnut, the animal favors large over small ones and eliminates, by probing the weight, empty shells. Scientists have determined that in a coniferous environment, squirrels can accumulate up to 3000 seeds and nuts in one season to cover their needs energetic. Still according to the researchers, the mammal quite quickly consumes the first third of its provisions – between September and January – then uses the rest from February to June, to complete its menu.

Does the squirrel have a method of hiding its provisions?

In periods of full activity, the small rodent devotes more than three quarters of his time to prospect, eat and hide his food. In animals, winter storage is broken down into two strategies : on the one hand, there are those who place all their reserves in a only hiding place, at the risk of being looted totality of their treasure by a competitor. And there are those, like the squirrel, who distribute their food all over their territory. By not putting all of their eggs in one basket, the rodent minimizes the possibility of a flight which would threaten its survival in winter. Rather wary, he often conceals the most large hazelnuts far from the tree where he found them in order to avoid their pilfering by a congener.

How does the squirrel know where its nuts are hidden?

It was long believed that the squirrel used a smell particularly developed to find the multitude of food stocks, several months after having constituted them. If the animal does use its sharp olfactory capacities to flush out its nest egg, it also has a very effective weapon: a part of its brain, called seahorse, indeed provides him with an incredible spatial memory. For scientists, the small mammal builds a kind of mental map of his pantry by first stacking his food in one place and then, from there, he divides his food into different hiding places depending on the type of hazelnuts. Other researchers have concluded that the memorization of the animal was operated through visual cuesincluding distance from trees or between hiding places. Particularly good at locating its reserves, the rodent would even borrow paths different ways to achieve this.

Can the squirrel have the wrong hazelnuts?

Through different experiments aiming to test the squirrel’s ability to find its provisions, the researchers observed that when several individuals hid their fruit close to each other, each returned to unearth its own reserves and not those of the neighbor. Studies have also shown that a squirrel, feeling spied on, was able to lure a fellow creature by rummaging in the foliage to make believe the development of a hiding place. Despite its techniques sophisticated, the animal never finds theentirety of its provisions. The success rate is estimated at 95% but the remaining percentage is not lost: by leaving a little stock buried in the soil, the rodent promotes the dissemination of seeds and the rejuvenation forests.