The southern right whale (Eubalaena australis) is a baleen whale, one of three species classified as right whales belonging to the genus Eubalaena. Like other right whales, the southern right whale is readily distinguished from others by the callosities on its head, a broad back without a dorsal fin, and a long arching mouth that begins above the eye. Its skin is very dark grey or black, occasionally with some white patches on the belly. The right whale's callosities appear white due to large colonies of cyamids (whale lice). It is almost indistinguishable from the closely related North Atlantic and the North Pacific right whales, displaying only minor skull differences. It may have fewer callosities on its head and more on its lower lips than the two northern species. Approximately 12,000 southern right whales are spread throughout the southern part of the Southern Hemisphere.
The maximum size of an adult female is 18.5 m (61 ft) and can weigh up to 80 tonnes (79 long tons; 88 short tons). The testicles of right whales are likely to be the largest of any animal, each weighing around 500 kg (1,100 lb). This suggests that sperm competition is important in the mating process. Right whales cannot cross the warm equatorial waters to connect with the other (sub)species and (inter)breed: their thick layers of insulating blubber make it impossible for them to dissipate their internal body heat in tropical waters.
In recent years, genetic studies have provided clear evidence that the northern and southern populations have not interbred for between 3 million and 12 million years, confirming that the southern right whale is a distinct species. More surprising is the finding that the northern Pacific and Atlantic populations are also distinct, and that the Pacific species (now known as the North Pacific right whale) is more closely related to the southern right whale than to the North Atlantic right whale.
The Southern right whale is listed on Appendix I of the Convention on the Conservation of Migratory Species of Wild Animals (CMS) as this species has been categorized as being in danger of extinction throughout all or a significant proportion of their range.From Wikipedia
Mother and calf