Watch this mama bear carry her cubs across a river on her back

David Roseman, an employee at Alaska's Wood Tikchick State Park, spotted this big bear carrying her cubs across the river on her back. Sweet video below. From National Geographic:

Wayne Kasworm, a grizzly bear biologist with the U.S. Fish and Wildlife Service, explained that bears' high fat content and oily coat helps them easily stay afloat. The bears, which he estimates to be about six months old, will likely start to swim on their own once they reach 30 pounds.