That's One Tough Chipmunk

Science News_ v. 166, 7/24/04, p. 6

"Chipmunks in Wisconsin toughed out ice age"

This article claims that "At the beginning of the last ice age about 40,000 years ago...some chipmunk populations stayed in northern refuges" according to a report in the July 13 Proceedings of the National Academy of Sciences.

Obviously, nobody actually observed such a thing. It's based on comparisons of mitochondrial DNA, using the "molecular clock" assumptions as well as the standard cladistic comparisons.

They used chipmunks from "Wisconsin, Illinois, Indiana and Michigan." Other results are that "the most recent common ancestor of all those chipmunks lived about 200,000 years ago" but "The most recent ancestor of the western-zone chipmunks probably lived less than 50,000 years ago."

So some chipmunks supposedly "rode out the last ice age in a hospitable zone." It might be interesting to look up some sources on the ice age and determine just how inhospitable the area at the time has been regarded. Wasn't Wisconsin supposed to be covered by a massive ice cap at the time?

Until Next Time,
David Bump