BrainStuff Classics: How Do Squirrels Organize Their Nuts?

Research suggests that squirrels use memory strategies to remember where they put the good nuts. Learn more in this classic episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff,
Lauren foc Obam here with another classic episode from our
former host, Christian Saga. If you've ever watched squirrels going
about their squirrel business, you may have wondered whether there's
any method to their for lack of a better term,

(00:22):
nut madness. It turns out they're very well. Maybe a
brain stuff is Christian Saga here. Despite how common North
American tree squirrels are in many cities, neighborhoods and outdoor spaces,
a big misconception exists about these little critters. Tree squirrels
store their food tree fruit like acorns in their nests

(00:46):
or dens to snack on all winter. Here's the thing
they actually don't do that. First, it's important to know
that both the Eastern gray and Eastern fox squirrels dine
on a varying menu of seeds, nuts, ache horns, tree buds, berries, leaves,
parts of pine cones, and other food some of us
well we don't like to think about, like bird eggs

(01:08):
and nestlings, and as well, you know they'll have the
occasional slice of found pizza. Some of that stuff they
eat right away. The rest they take to the nest
or den for later. But when winter approaches, squirrels are
faced with a challenge. They know instinctively that food sources
will soon be scarce, so they gather all the food
they'll need while also keeping themselves fed day today. That's

(01:32):
why they're so busy in the fall, when mother nature
has made sure that all the acorns have fallen from
the trees. Second Eastern gray and Eastern fox squirrels are
scatter hoarders, which means pretty much what it sounds like.
They hoard their food and then scatter it in locations
where they can easily access it. That's usually close to

(01:54):
the tree holding their nest or den, but they often
expand into areas of set been acres or two point
eight hectic ers, and rather than leaving their goods above
ground where other squirrels can steal them, they bury them
and this is called cashing about an inch maybe two
point five centimeters under the soil, and squirrels are known

(02:17):
to crack open a nut before burying it so they
can keep it from germinating. When it comes time to eat,
they forage for the nuts they buried. While squirrels possess
a strong sense of smell, which allows them to sniff
out nuts from under a blanket of dirt. Researchers have
long noticed evidence of strategic intelligence in the placement of

(02:38):
their food. For instance, one study in two thousand eight
reported that Eastern gray squirrels engage in what's called deceptive cashing.
They dig a hole, pretend to throw the acorn in
while they hold it in their mouth. Then they cover
up the empty hole and run off to another secret
stash place. And they do this it was suggest it

(03:00):
to fool other squirrels who might be watching them. But
a new study from professors in the Department of Psychology
at the University of California at Berkeley and published in
the September issue of the journal Royal Society of Open Science,
claims that tree squirrels use a pneumonic technique called spatial

(03:20):
chunking to sort out and bury their nuts scores by size, type,
and perhaps nutritional value and taste. Now when they're hungry later,
it's theorized they can remember where to find what they want.
In other words, the squirrels put specific nuts in similar
places to help them remember what nuts were where. I e.

(03:43):
Almonds were placed in one general area, hazel nuts in another,
and I guess pizza would go in a third area.
Thisnemonic strategy has also been seen in rats. The finding
researchers right in the studies show that a scatter hoarder
could employ spatial chunking during cash distribution as a cognitive
strategy to decrease memory load and hence increase accuracy of retrieval.

(04:09):
Squirrels have got a lot to think about. In other words,
they need all the memory tricks they can get. So
the next time you see a squirrel digging up a nut,
know that she might have just found the exact one
she was looking for. Today's episode was written by Jamie

(04:29):
Allen and produced by Tristan Neil and Tyler Clang. For
more on this than lots of other topics, visit how
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