BOB HIRSHON (host):
Shrinking mammals. I’m Bob Hirshon and this is Science Update.
Mammals have been shrinking ever since our ancient ancestors started dispersing across the globe during the Pleistocene era. Those we killed off after we became highly efficient hunters were up to three times larger than those that survived, according to a study in the journal Science. University of New Mexico biologist Felisa Smith and her team analyzed mammal size data over the past 125,000 years, making predictions 200 years into the future.
FELISA SMITH (University of New Mexico):
If we don’t pay any attention to what we do, we’re going to end up with a planet where the largest animal is a cow.
Smith says selective hunting removed larger plant eaters and predators, profoundly altering earth’s landscapes and food webs. But today, habitat destruction drives extinction more than hunting, by preventing large mammals from maintaining sufficient home ranges. I’m Bob Hirshon for AAAS, the science society.
Story by Susanne Bard