do squirrels hibernate or migrate in winter
Do Squirrels Hibernate or Migrate in Winter?
The prevailing confusion about hibernation in squirrels might have something to do with the fact that there are 280-odd squirrel species in the world, and not all of them hibernate. So, what do the non-hibernating squirrels do in winter? Do they migrate to warmer parts, or do they simply remain in their drey? We shall find out soon enough.
Smart or selfish?
Marmots are defenseless against predators during hibernation. So they hibernate in groups, keeping the weakest members towards the outer edge of their hibernaculum.● Squirrels prepare for winter well in advance either by reviving their fat reserves―the hibernating species, or by collecting food and storing it in different places―the species that do not hibernate. Interestingly, those species that go with the second option, prepare three to four food stores, but don't mark them. Instead, they rely on their sharp nose, which helps them detect food stores in the ground even when it is covered with snow, to find it.
● As for hibernation, that will depend on which species you are taking into consideration. Most ground squirrels hibernate.
- The Arctic ground squirrel (Spermophilus parryii), for instance, hibernates for 7 to 8 months.
- Similarly, the Richardson's ground squirrel (Urocitellus richardsonii) and Alpine marmot (Marmota marmota) are known to hibernate for up to 9 months.
- Even the thirteen-lined ground squirrel (Spermophilus tridecemlineatus) and Franklin's ground squirrel (Spermophilus franklinii) resort to hibernation.
● During hibernation, these squirrels lower their body temperature to a few degrees below the ambient temperature in their burrow. As they rely on fat stores in their body for energy, they lose a lot of weight by the time they resurface. The case of chipmunks though, is a little different. They do resort to hibernation, but don't store fat like other hibernating species. Instead, they wake up every few days and feed on stored food. And when they wake up for feeding, they also bring their temperature back to normal.
Hibernation or Torpor?
Experts seem to be divided over the question of hibernation in squirrels, with some of them saying that they do not hibernate, but instead enter a form of dormancy known as torpor. Both hibernation and torpor are characterized by low body temperature, low metabolic rate, slow heart rate, and slow breathing. If at all, it's the time frame that sets them apart. While hibernation can go on for months or as long as winter lasts, torpor lasts for a short period; a few weeks at the max. (Also, there is a concept called daily torpor, where the animal undergoes dormancy for a part of the day.) In essence, torpor is as good as a shortened version of hibernation.