The southern right whale has a circumpolar distribution and inhabits sub antarctic water between about 30° and 55° south. The whales migrate south during the summer months when supplies of krill are more prolific, and north during winter and spring to mate, calve and rear their young. They appear around the South African coastline from May to December. They can be seen interacting in the sheltered bays and coves close inshore and near river mouths.
Southern right whales were one of the first species to be hunted. Between 1805 and 1844, an estimated 40000 to 45000 were killed.
Right whales were named because when whaling started they were considered the "right"whale to hunt. This is because they are very slow (and therefore easy to approach), they live close to shore and float when they die. They provided large quantities of oil, meat and whalebone.
Southern right whales came close to extinction but have been protected since 1937.
New-born calves are between 4.5 and 6 metres (14ft 9in - 19ft 9in) in length. Adults can be between 11 and 18 metres (36-59ft) long. At birth, the southern right whale weighs about 1 tonne. Adults weigh between 30 and 80 tonnes. The southern right whale feeds on a diet of krill and/or other crustaceans.Southern right whales are slow swimmers but are often seen partaking in acrobatic activities! They wave their flippers above the surface, breach (up to 10 times in a row), flipper-slap and lobtail. Southern right whales also tip themselves upside-down vertically and wave their flukes in the air. 'Sailing' is another popular activity, which involves using the flukes to sail in the wind! They sometimes swim near the surface with their mouths open, displaying their baleen. Southern right whales live in small groups of up to 12 individuals. They are more commonly found in groups of 2 or 3, though they may gather in larger groups at feeding grounds. When they are in a small group, they will often take it in turns to come to the surface. They are also known to bellow and moan when visiting breeding grounds.
These lively animals are very social, normally travelling in groups of 20 to several hundred, and at times the group could be as big as several thousand individual animals. These pods are generally the largest in September and October, averaging about 115 individuals, whereas in the winter months the herds are usually only 35 members large. They are also highly inquisitive and will often investigate strange objects such as boats and divers. Communicative behaviour includes slapping the head or tail flukes on the water. The spectacular leaps are natural behaviour in the wild. They are very playful, leaping high out of the water and surfing in the breakers near shore. Group size peaks in the fall because this time of year is breeding season for these animals. Once they reach maturity, Dolphins begin reproducing and have a gestation period (pregnancy) of 10-12 months. At birth, these marine mammals are about 1m (3 ft) in length. It is likely that calves are born in summer or early fall.
Two subspecies are found off the South African coast: Tursiops truncatus reaches over 3m in length and favours colder, offshore waters; Tursiops aduncus is a smaller subspecies which favours warmer inshore waters, grows up to 2.5m and is the type most commonly seen from or near the shore.
Dolphins eat a wide variety of fish, squid, and crustaceans. They are known to hunt cooperatively - after herding a school of fish into a tight ball, some individuals will feed while others guard the school's perimeter to prevent the prey escaping. They are also known to associate with fishing boats. In various places around the world they actively cooperate with humans to catch fish, such as by herding fish into the fishermen's nets.
A major cause of mortality is human fishing activities. Drift nets and gill nets capture and drown many animals, as do abandoned "ghost nets" and other human debris. Estimating the deaths from these causes is very difficult. Shark nets are also indiscriminate dolphin killers. In various parts of the world, bottlenose dolphins are killed deliberately, for food or sport, by shooting or gaffing. New threats include depletion of prey by overfishing, and increasing levels of chemical pollutants such as organochlorides in the oceans, and uncontrolled eco-tourism.