Denny's Soapbox

Can squirrels remember where they have buried their acorns? Or do they simply rely on a hit-or-miss scent detection method of locating caches of nuts? Biologists and animal behaviorists have long puzzled over this question. For the most part it had been considered unsolvable; after all, it is very difficult to determine whether a squirrel has located an acorn by scent or by memory. And that was that. At least until biologist Lucia Jacobs of the University of Pittsburgh recently decided to investigate the nut-burying habits of squirrels for her doctoral dissertation.

Jacobs released several tame squirrels into an outdoor arena along with ten hazelnuts. All the squirrels participated in burying the nuts. That done, each squirrel was removed for a two- to ten-day period before being turned loose once again into the arena to have a go at nut detection. But unbeknownst to the squirrels, Jacobs had removed their buried nuts and substituted an identical number of different ones in the same holes, thus eliminating the smell of “their” nuts. She’d also added nuts in locations not originally chosen by the squirrels. “In this way,” she explained, “I hoped to simulate the situation faced under natural conditions where a squirrel has a choice of two types of nuts – its own and its neighbors”.

As a result, despite the fact that the squirrels had buried the nuts as long as a week and a half earlier, and despite the confusing array of similar-smelling nuts Jacobs had scattered about, “each squirrel retrieved significantly more nuts from the hiding places it had chosen in the first place ...” thus indicating quite conclusively that, instead of relying on smell, squirrels rely on remembering where their nuts are buried.

Finally, after all this time and speculation, we know. Thanks, Dr Jacobs.