I start each morning with a workout to energize myself for the day. Today was no different. With my blood pumping, I played Beyoncé’s “Formation” and thought to myself, women are just really the best.
So it seemed quite natural that today I also came across research from a team led by biologist Cory Williams of Northern Arizona University that examined the behavioral differences of male and female Arctic squirrels in Alaska. Published in Royal Society Open Science, their work found that female squirrels tend to spend less time above ground finding food, probably because they have to care for their offspring in nests underground. When they aren’t underground, though, they’re more active than their male counterparts.
Arctic squirrels spend much of their time hibernating from the end of the summer to late spring in order to survive the cold winter months. During the few months above ground, they have a hefty to-do list: They have to eat to replenish energy stores lost to hibernation, store energy for next season, and mate.
During the time when they are not hibernating, female squirrels not only have to consume enough to keep themselves going, they have to produce enough energy to gestate and produce milk for their babies during the first few summer months of the active season. When they’re not foraging for food, they’re in the nest caring for their young. This means that when they are active, they’re busy—much more so than their male counterparts.
“It is not clear what [the males] are doing while above ground,” the authors write. “The additional time spent above ground may be simply to loaf/bask in the sun.”
The authors note that this could be because at extremely high Arctic latitudes, the ground stays cool even in the summer months. The males may just be trying to keep warm–while becoming more vulnerable to prey. While underground and nursing, females were more protected from predators like foxes, wolves, and eagles.
For their work, Williams and his team trapped a total of 30 female and 18 male squirrels from two sites in 2014 and 2015. They gave the squirrels little collars that were photosensitive to detect time above or under ground (during the summer this far north, it stays light most of the time), and accelerometers to track their movement. “The accelerometers work just like one in an iPhone,” Williams told Science. “They take measurements once every second in three axes of direction, which lets us measure the index of movement.”
The study was initially done to examine how squirrels use their energy throughout the seasons. Williams and his team hope to follow up this work by taking even more measurements of squirrels’ body chemistry as they undergo the complicated hibernation process. As they do, perhaps they’ll find more evidence for how female squirrels manage to provide for themselves and their offspring, or an explanation for male squirrel’s nap habits.