Delphinapterus

Delphinapterus is a genus of toothed whales containing a single living species, the beluga whale, one of two living members of the family Monodontidae. Belugas are known for their all white coloration, the absence of a dorsal fin, replaced by a dorsal ridge, and a large deformable melon used in echolocation; unlike most cetaceans their seven neck vertebrae are not fused, allowing lateral head movement. The genus has a discontinuous circumpolar distribution across Arctic and sub-Arctic waters near Alaska, Canada, Greenland and Russia, with a global population estimated around 200,000.