It’s too early for us (humans) to start thinking about winter with its short days, cold temperatures, and blah landscapes. But not too early for the 13-lined ground squirrels that live out on the short grass meadows and prairies near Fort Ridgley state park. For them, it’s a race to eat enough to fatten up so they can hibernate in their deep burrows before cold weather arrives and the grasses dry up and their seeds disperse.
These ground squirrels are aptly named for the 13 dark brown and white stripes that line their backs. They can be found anywhere there are grassy meadows in the central part of the North America from Texas to southern Canada. But you’ll only find them above ground for about six months of the year. The rest of the time they are hibernating (deep sleep) in a deep burrow beneath the prairie plants.
The coloration is apparently good camouflage for them as they run through blotchy patterns of grasses heavy with dark stripes of seed heads, and the striped pattern may help reduce their visibility to their number one predator – the Northern Harrier.
Sometime in October all the ground squirrels will disappear underground to sleep away the winter cold in a state of torpor in which respiration is profoundly depressed from 100-200 breaths per minute during activity to one breath every 5 minutes in deep torpor. In addition, they usually do not eat or drink for almost all of the hibernation period, but survive in a very low metabolic state by oxidizing their fat stores.