Southern Right Whales
SOUTHERN RIGHT WHALE
LENGTH: Males up to 15m; females up to 17m.
WEIGHT: 50 – 65 tonnes.
LONGEVITY: Southern right whales are estimated to live at least 50 years.
DIET: A variety of fish and squid.
GESTATION: 11 – 12 months.
CALF SIZE: Length 5 – 6 m; weight 3 – 5 tonnes.
SIGHTINGS: June – November (breeding season).
The southern right whale spends the summer months in the far Southern Ocean feeding, and then migrates north in winter for breeding. During this time, they are mostly found in the sheltered bays of the Cape Coast, and can spend up to five months a year here.
They pass their time playing, courting and nursing their newborn calves, often just metres from the shore. They are occasionally spotted in Mozambican waters.
Southern rights are massive, rotund, black animals, rounder and heavier than either the humpback or Bryde’s whale. Distinguishing features are a lack of a dorsal fin, the stubby square-ended flippers and the unusual pattern of wart-like growths on the head (called callosities).
The body is mostly dark bluish-black, often with an irregular white patch on the belly between the flippers and extending back to the genital area, visible when the animal rolls over. The blow of the southern right is also distinctive – the spouts from each of the two blowholes diverge, forming a V-shaped fan.
These whales form small social groups of usually less than six related animals. Southern rights often breach several times in succession. They are also well known for resting head down in the water for several minutes with only the flukes held aloft – this is called “sailing”. Other behaviours include flipper slapping, lobtailing and spy hopping. Southern rights are extremely inquisitive and will approach boats to investigate – a trait which often had terrible consequences for them in the past when they were hunted.
DISTRIBUTION AND HABITAT
When Southern rights are not in their summer feeding grounds close to Antarctica, they can be seen around the coasts of Argentina, Australia, Brazil, Chile, Namibia, Mozambique, Peru, Uruguay, Madagascar, New Zealand and South Africa.
These whales feed mostly on krill and plankton, which they sift from the Antarctic waters by slowly swimming through the drifting shoals with their massive, highly arched mouths opened wide. As many as 250 baleen plates hang from each side of their upper jaw.
Each plate is more than two metres long and very fine, allowing the animal to sift enough tiny marine organisms from the water to maintain its massive bulk. These whales appear not to feed at all in the breeding season.
The breeding season is during Spring, from July to October. The females generally calve every three years. Successive breeding seasons are spent mating, calving, and resting in a 3 year cycle. The rest year is needed to allow the female two feeding seasons to recover from the tremendous drain on her body reserves caused by gestating a four ton calf in just 12 months and suckling it for a further six months.
Right whales form breeding groups consisting of one female and up to seven interested males. The males in the group may mate in succession and the father of the calf will be the animal providing the highest volume of sperm.
When mating season ends around September, the males begin their journey back to the Antarctic. Around November, when the calves are a few months old, the mothers and calves will also begin their journey back.
In the days of whaling, southern rights were the ‘right’ whales to hunt – their slow speed (rarely above 10km/h) made them easy to harpoon, and once dead they tended to float, which made collection easier. Their massive bulk meant a far higher yield per animal.
The right whale was finally protected in 1935 after an estimated 200 000 met their death at human hands. At present, the population is recovering, but new threats continue such as pollution, direct human interference, collisions with cargo ships and oil tankers, and depletion of their food sources.