General facts about southern right whales
Globally there are 3 different species of right whale; the North Pacific right whale (Eubalaena japonica), North Atlantic right whale (Eubalaena glacialis) and the southern right whale (Eubalaena australis). These three species look similar, but are divided into 3 separate species because they are geographically and genetically isolated from each other. The first part of their scientific name (the genus) Eubaleana means ”true whale” and the second part (species) refers to where they occur ( japonica means Japan, glacialis means ice and australis means southern).
The most distinguishing characteristics of southern right whales are their large, robust bodies, v-shaped blow, lack of dorsal fin and large off white callosities on their heads. Callosities are patches of rough skin that calves are born with and over time these patches become colonised by barnacles and whale lice (giving them the whitish colour) which are transferred from the mother during suckling. Each pattern of callosities is unique to an individual and is used by researchers for identification purposes. Southern right whales have extremely large heads are approximately 30% of their body length. Females average 14m in length (max 15.5m) and weigh approximately 40 -50 tons and are slightly larger than males. The pectoral fins (flippers) of right whales are large (20% of body length) and rectangle in shape with a pointed tip. The bones in their pectoral fins are the same as those in our own fingers, a remnant of their evolution from land mammals. Southern right whales have a smooth, broad back, dark grey or black skin and a white belly patch (in variable size). About 3-6% of all southern Right Whales have white or light grey blazes on their backs (find out more about skin coloration in Cetaceans in a later post). Southern Right Whales differ from in that they don’t have throat grooves and therefore can’t extend the throat while feeding. Instead they skim feed at the surface, using their 400-540 baleen plates as a sieve. Their baleen can reach a length of 2.3 meters in length and are dark grey to black in colour.
Southern Right Whales are slow moving whales (0.4-3.6 km/h with a max of 15km/h), but can frequently be seen tail and flipper slapping. They regularly lift their tail when diving and can be seen “sailing” whereby they raise their flukes into the air, almost as if they are doing a handstand. Southern Right Whales normally dives for 10-20 minutes while feeding, but can hold their breath for up to 1h. When southern Right Whales feed, they use subsurface skim-feeding where they swim through patches of food (mainly krill) with their mouth open. The krill gets trapped on the baleen plates and the whale then flushes the prey items out of the baleen before swallowing it. They have also been seen feeding along the ocean floor in the same manner. Southern Right Whales need to feed on 600-1600kg of food per day to sustain themselves throughout the year. Southern Right Whales are not as vocal as humpback whales and seem to communicate less when a high number of individuals are in one area. Their vocalisations consist of a variety of low frequency sounds, most are inaudible above the surface, although a loud bellow has often been heard at night.
Why do southern Right Whale cows and calves swim so close to the beach? This is mostly due to the benefits of calm, warm waters where they both can conserve energy. It is thought that right whales also use the surf zone to avoid predators, such as Orca’s by masking their vocalisations in the noise created by the waves. They are mostly found over sandy bottoms since this prevents the calf from injury. Cow-calf pairs might also stay closer to shore to avoid other whales, in particular males attempting to mate with them, because they could potentially injure the calf or interrupt nursing. Females with calves generally spend their time in depths of 6.7-8.2m making it impossible for a male to swim in under her.
Please see next week’s post on southern right whales distribution and reproduction.
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– Hofmeyr-Juritz L.H. Best P.B. 2011 Acoustic behaviour of southern right whales in relation to numbers of whales present in Walker Bay, South Africa African Journal of Marine Science v.33 p.415-427
– Best P.B. Elwen S.H. 2004 Female southern right whales Eubalaena australis: Are there reproductive benefits associated with their coastal distribution off South Africa? Mar Ecol Prog Ser Vol. 269: 289–295,
– Elwen S.H. Best P.B. 2004 ENVIRONMENTAL FACTORS INFLUENCING THE DISTRIBUTION OF SOUTHERN RIGHT WHALES (EUBALAENA AUSTRALIS) ON THE SOUTH COAST OF SOUTH AFRICA I: BROAD SCALE PATTERNS MARINE MAMMAL SCIENCE, 20(3):567-582
– Whales dolphins and other marine mammals of the world (2006) by Hadoram Shirihai and Brett Jarrett. Prinston field guides 2006
– Smithers’ Mammals of Southern Africa a field Guide by Peter Apps Struik Nature edition 2012
– Jefferson T. Webber M. Pitman R. 2007 Marine mammals of the world: A comprehensive guide to their identification 1st edition
– Best PB 2007. Whales and Dolphins of the Southern African Subregion. Cambridge University Press.