I am rather surprised at all the attention the find mentioned in this article is getting. Some would think that these mammals caused the downfall of the dinosaurs, but the fossil record suggests a very different scenario. There is no evidence of possum-to-coyote–size mammals for the 70-odd million years that the dinosaurs ruled the planet. The only mammals able to remain uneaten were no larger than a rat, almost too small to be noticed.

Dan Peterson
Fort Campbell, Ky.

This article mentions that “researchers analyzed the . . . skeleton of a chipmunk-size creature that lived 150 million years ago. . . . The . . . limb bones suggest that the creature spent a lot of time digging.” Finally, paleontologists have discovered their own direct ancestor.

Bob Kanefsky
Mountain View, Calif.

From the Nature Index

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