Tens of thousands of walruses have squeezed onto small patches of Alaska's shore because of melting ice floes. Scientists say the loss of sea ice has forced the lumbering creatures into a mass migration to land. The huge number of walruses foraging in a small area makes cubs extremely vulnerable to being trampled, the Guardian reports.
Similar migrations happened in 2007 and 2009, when sea ice was also at or near record low levels. "When they no longer have a place to rest, they need to go some place and it's a long commute," a US Geological Survey biologist tells AP. "This is directly related to the lack of sea ice." Officials are trying to reroute flights to avoid spooking the animals.
(Read more walruses stories.)