Hi everyone, and welcome back to Curious By Nature.
My name is Marjorie and I'll be your host on today's episode.
We've got a really fun topic today, an animal that I really love seeing around: squirrels!
Joining us today is Dr. Joel Brown, Distinguished Professor Emeritus at the University of
Illinois at Chicago and a Senior Member in the Department of Integrated Mathematical Oncology
at the Moffitt Cancer Center, and a great friend of the Nature Museum.
Today, Joel will be sharing his knowledge of squirrels, so let's go check in with him.
Squirrels are very talkative animals what are they communicating to each other?
Squirrels are pretty wonderful, like many of us they talk with their hands or body.
They like using their tail a lot, that swish swish you see in the tail,
and that's often then associated with vocalizations.
Probably the nicest vocalization's kind of a mew kind of call
you often hear from gray squirrels is actually more of a contact call.
It's more of a "Here I am." Sort of "Where are you?"
Other types of calls can be a bit more like,
"You're getting too close, I have my personal space."
And so the squirrel then will actually announce to other squirrels
more of an aggressive, kind of throaty kind of sound that is sort of saying,
"Look, don't get any closer, please don't."
And then finally when there's like dogs or threats
gray squirrels and fox squirrels have slightly different vocalizations
but you can hear that cha-cha-cha-cha
it's always associated with a swish, swish, swish of the tail and what they're saying then is,
"I have spotted the threat."
They're kind of harassing the threat hoping that the threat will go away.
So Joel, are there other roles that squirrels play in ecosystems?
Well one of I think the coolest kind of contributions
of squirrels to our current forests, say in North America or around here,
is remember that just 20,000 years ago, here in Chicago was under hundreds of yards of ice
and as those glaciers receded you had deciduous forests, the various oak trees,
the hickories many of the trees we love, they were 100-200 miles south of here.
But they're back and so how did they get back here so quickly?
And in fact these forests are thought at times to have moved 50 to 100 yards per year.
Picture an oak tree getting up and walking that far.
So in fact it was probably a team effort.
What's kind of cool is we don't know but it seems very likely that things like blue jays
would have set the pace.
They tend to bury their acorns farther away from where the squirrels can get them,
so they may have dropped accidentally or buried acorns far from the edge of the forest.
And then the fox squirrels kind of like the forest edge so you can imagine the fox
squirrels coming along and as soon as a small oak forms they will then move to that oak tree
and begin planting acorns all around it.
And then the final painting, the final brush strokes of the forest,
would be the gray squirrels,
who like the more denser forests, coming along and kind of filling in the gaps.
So, collectively, as we look at the oak trees here, look at the oak trees further north of us,
as you go all the way up into Canada, I think we have the squirrels to thank for that.
So one of the questions we get all the time here at the Nature Museum is,
"Why don't I ever see any baby squirrels?"
So why is that?
The reason why you don't see the baby squirrels
is because squirrel mothers are wonderfully attentive.
In the life cycle or the year of a squirrel,
the squirrels will mate, then the females then will raise
two to four young and they will raise one brood of young usually in the late winter/early spring.
In fact right now they will have babies.
The babies exist as we speak.
And then again in the late summer and the fall.
What the mother does is she keeps her kids in the nest.
Now in the winter time that means somebody's attic
or it means a tree hollow.
If it's in the summertime, it's those balls of leaves that go by the wonderful name of drey.
Those dreys, those balls of leaves, provide the home within which the mother will raise her young.
She keeps the young in the nest, they do not actually emerge from the nest
until they are fairly close to adult size, maybe two-thirds to three-fourths of adult size.
So you have to have a discerning eye.
If a baby squirrel falls out of a nest, the mother will often pick up the baby,
climb right back up the tree, go back into the tree hollow.
She will collect her baby, she's very, very attentive.
She will even fight off dogs or other predators from her young.
And so the squirrels we actually see naturally are already almost adult size,
and so what you want to look for is they will begin to emerge,
you'll start to see them oh probably near the end of May/
middle of May, and you begin, if you have a careful eye you'll be able to notice
there's some slightly smaller ones.
And the way you can tell them they're just a little bit smaller,
their tails are not quite as bushy, their fur is perfect, but not really very long.
Squirrels are intelligent and social animals, can they recognize the people that they see often?
In terms of intelligence, I would say they have a very special kind of intelligence.
One is they have phenomenal memories for where they cache their food .
I's thought that they can remember where they have buried hundreds of nuts,
at least to within sort of a locality,
and so they find it much easier to find
the seeds that they have buried relative to the seeds of others.
Also they have an amazing tenacity for "if first you don't succeed, try, try again."
I think many people have experienced that with their bird feeders
and the squirrels trying to get on the bird feeder or the squirrels trying to access an opportunity.
Squirrels are persistent, when they see an opportunity
they will try and try again to leap, to get on it.
They will try different approaches.
Now in terms of their social intelligence so to speak, the fox squirrels and the gray squirrels
that live in our city they're not particularly social, they're not like prairie dogs
or some of the other squirrel species that form colonies and work together.
However, that doesn't mean that they hate each other.
They become very aware of each other.
So the squirrels probably get to know each other within a neighborhood within an area.
They're not territorial so they can have broadly overlapping home ranges,
so it's not unusual then to see in a park six, seven squirrels all in an immediate area.
The gray squirrels are a bit more social.
They will actually den together in the winter and they actually seem to learn from each other.
If one of them is having a lot of luck finding food,
guess what, the others will watch and see. Now in terms of you and predators,
they actually get to know the individual predators and people that live in that backyard.
So if you think the squirrels are watching you,
when you're around your house, they are!
They not only will get to know you individually and kind of what you do,
they will get to know the individual cats, dogs, and coyotes.
And they're very quick to learn, for instance,
that the cat when it does go out in my backyard is harmless.
Others have dogs that have captured squirrels or will go at squirrels with
a certain amount of enthusiasm you might even say ferocious towards squirrels.
The squirrels will eventually learn that that dog, not just all dogs, but that dog
is either particularly annoying or capable.
I'm such a nut for squirrels and I hope you are now, too.
Thanks again to Dr. Joel Brown for sharing his knowledge with us today,
and thank you all for watching.
Be sure to leave any questions you have about squirrels in the comments below.
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We'll see you back here next time on Curious By Nature.