During the last week of September, Inuit residents in the community of Arviat on the northwest coast of Hudson Bay were surprised to see a mysterious whale following a small boat heading back to the village. The whale was at least twice the size of the 15- to 20-foot-long beluga whales that are traditionally seen in this part of the world.

Based on the photos taken, scientists concluded that the whale was a humpback, the first ever seen in that part of Hudson Bay, and one of a handful that have recently been spotted in the North American Arctic.

Humpbacks are not the only marine mammals that have been expanding their range northward. Most notably, as sea ice melts, ice-avoiding killer whales have been moving deeper into the Arctic Ocean, hunting and killing both narwhal and beluga whales. Other whale species — including minke, bottlenose, fin, and sperm whales — are also making their way north as the Arctic heats up. At the same time, on land, grizzly bears, white-tailed deer, coyotes, and other animals and birds have been expanding their range into the warming boreal forest and Arctic tundra.

For the indigenous people who subsist on Arctic animals such as muskoxen, caribou, seals, polar bears, and eider ducks — species that are in decline in some places — the newcomers are potentially a welcome addition to their diet. But emerging evidence suggests that some of these newly arriving species may be bringing rare or novel pathogens to the Arctic. In recent years, a plethora of deadly and debilitating diseases have struck reindeer in Scandinavia and Russia, muskoxen on Banks and Victoria islands in Arctic Canada, polar bears and seals off the coast of Alaska, and eider ducks in northern Hudson Bay and the Bering Sea.

Read more at Yale Environment 360

Image: A male polar bear suffering from alopecia, which caused the patches of black on his neck and side. (Credit: MICHELLE VALBERG)