for National Geographic News
Mother moose use roads as a kind of human-made shield to protect their newborn calves from predatory bears, a new study has found.
In Wyoming's Grand Teton National Park, pregnant moose move closer than normal to paved roads before giving birth.
By cozying up to highway corridors, the moose can birth and raise their calves in relative safety.
"Bears tend to be more averse to roads than moose," said lead study author Joel Berger, a biologist with the Wildlife Conservation Society in Teton Valley, Idaho, and a professor at the University of Montana in Missoula.
Previous studies have shown that grizzly bears—the main threat to newborn moose—seldom venture within 1,640 feet (500 meters) of roads.
(Related photo: grizzly vs. moose [warning: graphic content].)
The bears' fear of whizzing traffic gives a huge advantage to moose moms willing to tolerate a little noise.
"The closest we've had an animal give birth to a road is less than 50 yards [45 meters]," Berger noted, although distances of a few hundred yards were more common.
"[Mothers and calves] hang out in these areas for several weeks until the calves are old enough to run from a bear," Berger said.
His study appears online this week in the journal Biology Letters.
Roads as Refuges
Berger's team tracked the locations of individually marked moose living in the Grand Teton region over a ten-year period.
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