After a month upstream, a female gray whale died early Tuesday morning when it became stuck on a sandbar in California's Klamath River. The 45-year old gray whale had been seen swimming in the river since June. It was accompanied by a calf until July 23, when the calf returned alone to the Pacific Ocean. Biologists don't know why the whale entered the river, nor why it stayed, although some have speculated that it was hiding from orcas. Repeated efforts to direct the whale back to sea were unsuccessful. Though rare, whales have been known to venture up inland water ways before. A Northern Bottlenose whale died in London's River Thames in 2006, and two humpback whales were seen 90 miles inland in California on Sacramento's American River in 2007 before swimming back to the ocean.
Read more at the Associated Press