Why Did the Squirrel Cross the Road?

Driving to lab one day as a grad student, I saw some ducks crossing the road. They crossed at a comfortable pace—not too slowly so as to suggest feelings of entitlement to the traffic they were holding up, but certainly not too quickly to suggest that they were afraid. They were aware, but confident. This routine wasn’t new to them.

While I watched, I had a somber thought: You know, I haven’t seen much, if any, duck roadkill. On my usual route to lab, squirrels were the regulars when it came to roadkill. But why not ducks? the scientist in me wondered. Did it have anything to do with the manner in which they crossed the road?

The squirrels crossed the road by darting swiftly, while the ducks walked to safety at a comfortable pace. The ducks generally crossed in groups, while the squirrels usually did so alone. Was the debonair gait of the ducks a result of an inner courage, or just a naive lack of awareness of the danger around them? Was the erratic behavior of the squirrels motivated by fear, or was there something fierce and admirable about their decision to cross a busy road alone?

The science of courage

While it is difficult to know the true motivations behind the way animals act, scientists are beginning to shed light on this mystery and make sense of some of the most elusive behaviors of animals, including those of the domestic cat. A recent article in Science magazine reported a study had resolved the mystery behind why cats eat grass; the theory is that it’s actually an instinctual and beneficial behavior for cats and other animals, helping them “expel intestinal parasites by increasing muscle activity in the digestive tract.” Another study attached cameras to cats and documented the differences in their behaviors when inside the homes of their owners, vs. outside. But does something happen at a molecular or cellular level to explain the mechanism behind these types of behaviors?

Recently, scientists studying mice identified a part of the brain called the vMT (ventral midline thalamus) that is more active in mice that are exposed to a simulated predator, than in mice that are not. When scientists mapped out the nerve tracts of input and output signals in this part of the brain of these mice, they found that the inputs were broad (parts of the brain sent that sent signals to the vMT processed broad brain functions like arousal), but the outputs were selective (signals that arrived at the vMT were only sent to specific parts of the brain that process emotions like fear and anxiety).

Normally in nature when mice encounter predators like hawks and owls, their instinctual behavior is to do one of three things: freeze in place (hopefully a well-camouflaged place to avoid further detection), hide in a nearby shelter, or run for its life. In this study, when the scientists exclusively stimulated a specific tract of neurons, the mice frequently exhibited “courageous behavior”—instead of running away or hiding, they stood their ground, thumped their tails and ran around in open unprotected areas of their chamber.

Human brains have a similar part that functions like the vMT in mice. Perhaps ducks and squirrels do as well. The key to whether a creature (including humans) will react with fear or courage may need further study of the brain and nerve tracts. But shouldn’t we first have a working definition of courage?

What is courage?

When I first started teaching, I would get nervous when standing in front of a class full of students. It took me a while to realize that while I may not have felt courageous at the time, I was.

Courage doesn’t always look like a big heroic act of bravery. It could be the simple act of showing up and choosing to do something, despite how one feels. Courage does not mean that you are not afraid; probably the opposite. You are completely afraid, but you act despite being afraid. Courage without fear is probably not courage at all.

Now, I can’t tell whether the squirrels or the ducks that cross the road have more courage, but  the squirrels have a little more courage than I was initially inclined to give them credit for.

In life, I want to be a little more like the squirrels that cross the road. Maybe they don’t always get to the other side, but I admire what appears to be an inner courage that compels them to act, if not fearfully.

Now, I’m not saying that acting impulsively through fear is a good practice—although perhaps it is better to act in fear than not to act at all. I’ve had my share of making terrible decisions because fear blinded my better judgment, so I do not want to be like the squirrel in that manner.

But this much I know: I want to live more courageously despite my fears, and I’m okay if that means learning something from the critters that cross the road—or at least the ones that try.

Ciara Reyes-Ton has a Ph.D. from the University of Michigan in Cellular and Molecular Biology, and teaches at a college in Nashville.