Two killer whales that swam up Alaska’s Nushagak River are dead, presumably having succumbed to the stress of a prolonged period in fresh water. Two adult whales and a juvenile whale swam 30 miles up the river roughly three weeks ago. The juvenile was last seen on Saturday. Killer whales have a history of swimming inland in Alaska: biologists chased a pod of whales living in Alaska's Barnes Lake back to the sea by banging pipes underwater in 1994.
Read more at the Anchorage Daily News