Scientists suspected the whales were distinct, but since they are so rare it took years to prove. In 2019, one of the whales beached in the Florida Everglades. The stranding killed the whale and dealt a blow to the small population’s long-term stability, but it presented an opportunity for scientists.

Rosel was able to examine the skull of the whale in 2020, according to an article in NOAA Fisheries, adding to the evidence that helped formally identify it as a new species of baleen whale.

Pioneering biologist Dale Rice was the first to document the whales’ presence in the Gulf of Mexico, and the NOAA researchers who confirmed the species are naming it Balaenoptera ricei, or “Rice’s whales,” in his honor. Rice died in 2017 after a six-decade career.

The species is so few in number that it is protected under the Endangered Species and Marine Mammal Protection acts, where it was previously listed under its old name. Fewer than 100, and possibly as few as 33, remain, and they are threatened by ship collisions and oil spills. The 2010 Deepwater Horizon oil spill, the largest offshore spill in American history, is estimated to have killed 17 percent of the whales and affected the reproduction and health of much of the rest of the population.

Rice’s whales can weigh up to 30 tons, grow 42 feet long and live up to 60 years. They feed along the deep seafloor of De Soto Canyon, a heavily-trafficked area of the gulf about 60 miles south of Mobile, Ala.