Brown Bear Genetics Study

brown bear in grass
The first brown bears arrived in Glacier Bay from the east.

Population and landscape genetics of brown bears in Glacier Bay, Alaska
A study conducted in 2009-2010 examined the genetics of bears across Glacier Bay. Bear Hair DNA from 105 brown bears was collected from sites spanning across Glacier Bay National Park. Genetic and landscape analysis can be used to show how the landscape and population structure of brown bears are intertwined in Glacier Bay, and to help determine likely sources for brown bear re-colonization in the recently de-glaciated region.

Brown Bear Genetics Study Map
Brown Bear Genetics Study Map


Results show that there are three genetically distinct groups of brown bears in Glacier Bay and that the rugged Fairweather mountain range and the wide fjords of Glacier Bay are both barriers to dispersal. Two genetic groups range far beyond the park boundary to the west and east, and one group was isolated long enough to undergo genetic drift and develop a genetic signature unique to northern Glacier Bay. This endemic subpopulation likely stems from an original group of colonizers from the east, while bears from the other two groups are more recent immigrants.

One recently immigrated group likely moved into the bay from the northwest, the other arrived from the northeast, and represent a second wave of colonization along the shoreline of Glacier Bay. These recent immigrants are beginning to mix with the original colonizers after years of separation, and soon the unique genetic signal of the original colonizers will vanish.

Lewis TM, Pyare S, Hundertmark KJ (2015) Contemporary genetic structure of brown bears (Ursus arctos) in a recently deglaciated landscape. Journal of Biogeography 42:1701-1713. doi: 10.1111/jbi.12524


Last updated: February 3, 2019

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Glacier Bay National Park & Preserve
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Gustavus, AK 99826


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