Mammals shrink when Earth heats up, study says

A new study suggests global warming often leads to global shrinking of mammals.

Using fossil teeth found in Wyoming, researchers say mammals including our earliest primate ancestor shriveled a bit in size at least twice in Earth's history when temperatures spiked.

University of New Hampshire scientist Abigail D'Ambrosia warns that mammals — but not people — could shrink in the future under even faster man-made warming that's going on now.

When Earth warmed suddenly and naturally about 54 million years ago, three different species shrank noticeably. An early small horse got 14 percent smaller, going from about 17 pounds (7.7 kilograms) to 14.6 pounds (6.6 kilograms).

The study is in Wednesday's journal Science Advances.