There are three recognised species of rights. By studying the genetics of parasitic whale "lice", scientists estimate the split ocurred 5-6 million years ago. They are so called because they were the "right" whales to hunt - slow, swimming close to shore and would float when killed.

The right whale has been protected since the 1930s, although illegal Soviet whaling took large numbers in the North Pacific and Southern Hemisphere up to the 1970s. Two of the three species are on the brink of extinction. There are only about 200 surviving in the North Pacific, and perhaps fewer than 400 in the North Atlantic.

The Southern Hemisphere species numbers about 8,000 to 10,000.

Status: Endangered (North Pacific and North Atlantic species) and Least concern (Southern species)