This is some information about right whales from National Geographic.
Right whales are the rarest of all large whales. There are several species, but all are identified by enormous heads, which can measure up to one-third of their total body length. These whales' massive heads and jaws accommodate hundreds of baleen "teeth." Rights and other baleen-feeding whales use a comblike strainer of baleen plates and bristles to ensnare tiny morsels of food as they swim. Right whales feed on zooplankton and other tiny organisms using baleens up to 8 feet (2.4 meters) long.Southern and the two species of northern right whales live in temperate Atlantic or Pacific waters, often near the coast.Right whales were named by whalers who identified them as the "right" whale to kill on a hunt. These leviathans had enormous value for their plentiful oil and baleen, which were used for corsets, buggy whips, and other contrivances. Because of their thick blubber, right whales also float accommodatingly after they have been killed. Populations of these whales were decimated during the whaling heydays of the 17th, 18th, and 19th centuries. During this period they came close to extinction.Because females do not become sexually mature until ten years of age and give birth to a single calf after a yearlong pregnancy, populations grow slowly.All species of right whales are endangered and have enjoyed complete international protection since 1949. Several thousand southern right whales are believed to survive, and they have shown some encouraging population growth since their protection. South Africa's population is believed to have grown from 100 to 1,000 animals since 1940.Northern right whales are the most endangered of all large whales. They number only several hundred, and populations do not appear to have grown in the decades since their protection began.