Also known as killer whales, orcas are considered the second-most widely ranging mammal species on the planet, after humans. The southern resident population, found off the Pacific coasts of North America, was listed as Endangered under the Canadian Species at Risk Act in 2003 and the U.S. Endangered Species Act in 2005. Among several other threats, these orcas face increasing ambient noise levels associated with shipping and other vessel traffic. New threats are emerging from seismic blasting associated with offshore oil exploration.