FILE - In this April 18, 2004, file photo provided by the U.S. Fish and Wildlife Service, Pacific walrus cows and yearlings rest on ice in Alaska. The Trump administration will not add Pacific walrus to the threatened species list. The U.S. Fish and Wildlife Service announced Wednesday, Oct. 4, 2017, that it can't say with certainty that walrus are likely to become endangered despite an extensive loss of Arctic sea ice due to global warming. (Joel Garlich-Miller/U.S. Fish and Wildlife Service via AP, File)