AUDIE CORNISH, HOST:
Some birds and insects have an innate drive to migrate - not so for big-hoofed mammals like sheep or moose. NPR's Nell Greenfieldboyce reports on a surprising new study that shows these animals have to learn to migrate, and they are not exactly quick studies.
NELL GREENFIELDBOYCE, BYLINE: Brett Jesmer is an ecologist at the University of Wyoming. He says there have long been hints that large mammals aren't born knowing how to migrate but learn from their parents.
BRETT JESMER: So biologists might be in the field observing moose, and they see that the moose calf followed its mother on its spring and fall migration.
GREENFIELDBOYCE: Moving from place to place to follow new, green grass. To see if knowledge about migration really was passed down from generation to generation, he and his colleagues studied moose and bighorn sheep in the western U.S. Some populations had lived on the same land for a long time.
JESMER: We know they were there at the time of the Lewis and Clark expedition and probably for hundreds or even thousands of years prior.
GREENFIELDBOYCE: Others had moved in over the last 60 years as conservationists brought animals to areas where the original populations had disappeared due to hunting or disease. What the researchers found using GPS tracking and satellite imagery is that animals put into vacant, unfamiliar land didn't migrate. Matt Kauffman is a wildlife researcher at the U.S. Geological Survey.
MATT KAUFFMAN: That was sort of a - little bit of an aha moment for me of, like, wow, they really have to learn where things green up and where they need to move next.
GREENFIELDBOYCE: In the journal Science, the researchers say it took bighorn sheep nearly 40 years to develop a robust migration. It took moose nearly 90 years. The study impressed Jacqui Frair. She's a wildlife ecologist at the State University of New York in Syracuse.
JACQUI FRAIR: The dimension that they're bringing to migration ecology is memory and cultural transmission of information.
GREENFIELDBOYCE: She says this shows we need to protect animals' existing migration routes now because there's no easy fix if a migration culture is lost. Nell Greenfieldboyce, NPR News.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.