Natures wonders: mule deer migration understood (Introduction)

by David Turell , Saturday, August 24, 2019, 18:41 (1916 days ago) @ David Turell

Mule deer migrate in Western USA each year and they appear to know the geographic routes:

https://phys.org/news/2019-08-migrating-mule-deer-dont.html

"Recent research from the University of Wyoming has found that memory explains much of deer behavior during migration: Mule deer navigate in spring and fall mostly by using their knowledge of past migration routes and seasonal ranges.

"The study found that the location of past years' migratory route and summer range had 2-28 times more influence on a deer's choice of a migration path than environmental factors such as tracking spring green-up, autumn snow depth or topography.

"'These animals appear to have a cognitive map of their migration routes and seasonal ranges, which helps them navigate tens to hundreds of miles between seasonal ranges," says the lead author of the paper, Jerod Merkle, assistant professor and Knobloch Professor in Migration Ecology and Conservation in the Department of Zoology and Physiology at UW.

***

"The UW team found it is not that simple. Without the intrinsic factor of landscape memory to guide deer between seasonal ranges, the long-distance corridors of western Wyoming's Green River Basin, for example—exceeding 300 miles round-trip in some cases—would not exist in their present form.

"'It appears that green-wave surfing helps them determine when to move within a kind of 'map' in their brain," Merkle says. "The timing of spring green-up determines when an animal should migrate, but spatial memory determines where to migrate."

***

"'This is yet another study that makes clear that animals must learn and remember how to make these incredible journeys," say Kauffman, who leads the Wyoming Cooperative Fish and Wildlife Research Unit, where the research was conducted. "This is critical for conservation, because it tells us that, to conserve a migration corridor, we need to conserve the specific animals who have the knowledge necessary to make the journey."

"The study bolsters the findings of a 2018 paper in the journal Science by a UW-led team that found translocated bighorn sheep and moose with no knowledge of the landscape can take anywhere from several decades to a century to learn how to migrate to vacant habitats.

***

"This suggests that the migratory routes we see today are optimized across generations for green-wave surfing in large landscapes. These learned migration corridors are not readily discoverable by animals if they cannot access the memories established by past generations."

Comment: It is only 300 miles but still amazing that they have maps in their heads. Birds and insects that travel thousands of miles use the magnetic fields, as do salmon.