52-hertz whale

The 52-hertz whale, an unidentified whale species in the north Pacific Ocean, calls at an unusually high frequency of 52 hertz—much higher than the 10-39 Hz range of blue whales or 20 Hz of fin whales—and has been detected annually since its discovery in 1989. Originally believed to be solitary and earning the nickname "the world's loneliest whale," evidence since 2010 suggests there may be at least one other whale calling at the same frequency. Scientists at Woods Hole Oceanographic Institution remain unable to identify the species and speculate it could be malformed or a hybrid, though the whale appears healthy and follows a migration pattern between the Aleutian Islands and California coast.