Oct 23 2015
Every autumn I miss the moment when the chipmunks disappear.
For weeks they’re vocal and active while they gather food to store in their underground burrows for the winter. Then one day they stay underground and go to sleep. Days or weeks later it dawns on me, “I haven’t seen a chipmunk in a while.”
Chipmunks (Tamias (Tamias) striatus) are not true hibernators. Instead they go into periodic bouts of torpor in which they lower their body temperature and sleep deeply, then wake up to eat and defecate. On warm winter days we see them out foraging.
Ironically an unusually warm winter is fatal to chipmunks. A study by Craig Frank at Fordham University found that chipmunks are less likely to enter torpor when the weather’s warm. Those who do enter torpor have an 90% winter survival rate. If they stay awake in warm weather, they die. (90% mortality. Yow! Climate change is bad for chipmunks. Click here to read more.)
Some day soon the chipmunks will go underground, enter torpor, and not resurface until a warm winter day. Will we notice their absence?
Here today, asleep tomorrow.
(photo by Chuck Tague)