Have you seen any chipmunks or groundhogs lately? Silly question, you might say. It’s February and they’re hibernating. Maybe so, but it’s also mating season for these burrowing rodents and they’re out-and-about during the day looking for love — rain, snow, or shine. As a matter of fact, it would have made more sense if Punxsutawney Phil emerged from his burrow on Valentine’s Day rather than February 2 because he might have seen his sweetheart instead of his shadow.
Chipmunks and groundhogs are part of a family collectively known as ground squirrels in some parts of the country — a family that includes gophers and prairie dogs as well. During the winter months, all of these animals retreat into their burrows to snooze the winter away. Until February, that is. That’s when the rodent version of cupid comes calling.
Chipmunks hibernate during the winter, but they don’t sleep all the way through the season. They retreat into their burrows and awaken every few days, raise their body temperatures to normal, feed on previously-stored food, and then urinate and defecate. Their burrows are divided into different chambers for each of these purposes. But when chipmunks are in the sleep phase of hibernation, they may be difficult to arouse. Their heart rate slows from about 350 beats per minute to less than 10 and their body temperature drops from 94 degrees to whatever the temperature is inside the burrow — sometimes even as cold as 40 degrees F.
Things are a bit different for groundhogs, also known as woodchucks. They undergo a radical change as they enter into a state of hibernation after the first hard frost in the fall and their heart rate slows from about 80 beats per minute to 4 or 5 beats per minute. They don’t wake up to eat like chipmunks do but survive on a layer of stored fat acquired during the previous summer and fall instead. A groundhog’s body stays barely above the ambient temperature inside its burrow, dropping from 98 degrees to as low as 38 degrees. Both sexes of groundhogs are loners and hibernate accordingly. But in February, males awaken to make house calls on the burrows of any nearby females to make sure someone is home. They may check on the burrows of several females before returning to their own to resume the hibernation process until March when it’s time for them to actually mate. Then they’ll make the rounds again.
So if you happen to see a chippie or chuckie out and about this month, now you know why.