Squirrels are everywhere on North Dakota State’s campus, and students have shown their fascination with the small rodents on social media sites and apps.
Two squirrel species are native to North Dakota: the eastern gray squirrel, Sciurus carolinensis, and the American red squirrel, Tamiasciurus hudsonicus.
Squirrels have been in the state at least since the last glacier receded from the region about 11,400 years ago.
During the winter, the squirrels do not hibernate or enter torpor, short periods of time when the body temperature is decreased. They survive by staying very active.
Squirrels also communicate with each other. The social call of the red squirrel sounds “chatter-like.” People hear this often because red squirrels like to defend their territory and are aggressive.
Red squirrels are much smaller than gray squirrels. However, the red squirrels are more aggressive. Their aggressive behavior is why people walking through campus may see red squirrels chasing gray squirrels.
Even though the squirrels seem very aggressive toward one another, they are quite comfortable occupying the same space as humans.
“Urban populations of squirrels are habituated to humans. This means that due to repeated exposure, they have lost any natural fear they have of humans (or it is significantly reduced),”said Erin Gillam, an assistant professor of biological sciences at NDSU. “I am sure they have also come to associate humans with food, likely further reducing any fear.”
Not only do squirrels adjust to being around humans and living in urban areas, they also can adjust to cars and bikes.
“The squirrels thrive on campus, because they are adapted to live in this environment,” Gillam said. “As an extra benefit to them, these urban populations have learned to exploit human garbage as a food resource; this is the primary reason they are often particularly dense in urban areas.”
The process is known as synurbanization, Gilliam said.
“There are many examples of animals in urban populations exhibiting significant physical and behavioral differences from their rural/natural ecosystem counterparts,” Gillam said.
Due to synurbanization, urban animals typically live in higher population densities, producing more offspring, are more likely to be larger in size and are less fearful of things they encounter regularly in an urban environment.
Squirrels have the ability to thrive in urban environments because they are generalist foragers and can eat a wide variety of food types.
“They are also rather opportunistic, in that they will exploit whatever food sources are most readily available and will try out novel foods that they find,” Gillam said.
Like any other wild animal, humans should not be feeding squirrels.
Squirrels have big, robust jaws and being bit by one hurts and could potentially cause serious injuries.
“Feeding the squirrels is bad because it teaches them to lose their fear of humans,” Gillam said. “You don’t want to increase the interaction between humans and squirrels, because that increases the chance of something bad happening and being bit.”
Like humans, squirrels require a balanced diet and feeding them human food could be dangerous to them.
Campus can expect to see them for many years to come because the squirrels are not going anywhere.