Beluga whales and narwhals live solely in the cold waters of the Arctic and sub-arctic. Smithsonian scientists, however, found that this may not have always been the case. They recently described a new species of toothed whale and close relative to today’s belugas and narwhals that lived some 3-4 million years ago during the Pliocene in warm water regions.

Beluga whale, narwhal and Pliocene relative Bohaskaia monodontoides shown in artist impression by Carl Buell

Why and when its modern-day relatives evolved to live only in northern latitudes remains a mystery. The team’s research was recently described in the Journal of Vertebrate Paleontology.

This new species, Bohaskaia monodontoides, is known only from a nearly complete skull found in 1969 in a mine near Hampton, Va.

Since its discovery, the skull has been housed in the paleontology collections of the Smithsonian’s National Museum of Natural History. It was loosely identified as belonging to a beluga whale but it had never been closely studied.