Dog Days

By David Orenstein / September/October 2015
August 31st, 2015

Old dogs can teach humans new things about evolution.  After studying North American dog fossils from as far back as 40 million years ago, Brown scientists have concluded that changes in climate can directly impact predators as well as animals who feed only on plants.

Courtesy Mauricio Anton
“Although this seems logical,” says one of the study’s authors, Christine Janis, a Brown professor of ecology and evolutionary biology, “it hadn’t been demonstrated before.” The conclusion suggests another evolutionary change that could be triggered by climate change.

Fossils show that 40 million years ago dogs, which are native to North America, had adapted to their wooded habitat as small animals that looked more like mongooses than today’s canines.

Beginning a few million years later, the North American climate cooled, the Rocky Mountains expanded, and the continent’s interior became drier. As forests slowly gave way to open grasslands, dogs responded by evolving from ambushers to pursuit-pounce predators similar to modern coyotes or foxes and ultimately wolves.

The lead author of the study, whose results were published in Nature Communications, was Borja Figueirido, a former Brown Fulbright postdoctoral researcher. He and Janis argue that today’s climate change will likely further affect dogs’ evolution.
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September/October 2015