Southern right whales apparently have the highest degree of kidney lobulation noted in mammals. It was determined by Kamiya (1958) that a kidney weighing 32.4 kg from a 11.7-meter long female had 5,377 reniculi, many of which were fused. When compared to other cetaceans, southern right whales have at least five times the amount of kidney reniculi (Cummings 1985).
Perception Channels: tactile ; chemical
Southern right whale populations are showing a slow increase since international protection in 1935, when over-exploitation nearly eradicated the species. There are estimated to be approximately 3,000 to 4,000 currently surviving in the southern hemisphere. Aside from international protection, individual countries are also protecting these whales and improving their ability to survive and reproduce. In Brazil the Right Whale project has been in effect since 1981. The program's goal is to protect the whales in their breeding grounds off the coast of South Brazil. Program participants monitor and research the current situation, and inform the public about the importance of environmental protection. Since its establishment, the program has, among other beneficial actions, gotten the government for the State of Santa Catarina to declare the southern right whales a state natural monument, thereby assuring its full protection. Other countries have also vowed to minimize human impacts on whale populations. This idea has been followed through by reducing direct disturbance and coastal industrial activity, as well as increasing awareness of the hazards of oceanic dumping that may lead to bioaccumulation and possible extinction.
US Federal List: no special status
CITES: appendix i
IUCN Red List of Threatened Species: critically endangered
Although very rarely found stranded along beaches, southern right whales occasionally do cause harm to themselves and, indirectly, humans. They have collided with large vessels and entangled in fishing gear. This causes a loss or reduction of possible shipping routes (in order to avoid collisions) and an increased cost to the fishing industry.
For the past ten or fifteen years, humans have capitalized on southern right whales, as well as other whales and aquatic mammals. Currently, the increasing popularity of whale watching and coastal tourism has led to the whales having a positive economic impact on humans. The development of whale watching has promoted economic benefits to coastal communities while increasing the protection and awareness of the species - stressing the importance of environmental quality and conservation. This benefit to the whales and their habitat contrasts sharply with previous economic exploitation of southern right whales. They were extensively hunted for oil and meat before becoming protected.
Using their long and numerous baleen plates, southern right whales feed on small plankton, including pelagic larval crustaceans and copepods. They are most often observed using one of two feeding techniques. The first, surface feeding, occurs when the whales selectively swim through densely-populated plankton slicks with their mouths wide open and baleen exposed. The other method occurs while submerged, presumably in highly dense populations of plankton.
Animal Foods: zooplankton
Foraging Behavior: filter-feeding
Primary Diet: planktivore
Found only in the southern hemisphere, southern right whales have a circumpolar distribution between 30 and 50 degrees south, inhabiting sub-Antartic waters (Ridgeway 1985).
Biogeographic Regions: atlantic ocean (Native ); pacific ocean (Native )
While avoiding warm equatorial regions, southern right whales remain near continents and island masses.
Aquatic Biomes: coastal
Average lifespan
Status: captivity: 70 years.
Southern right whales are characterized by their uniformly dark color and white callosities found on and around the head. Callosities, which are outgrowths of tough skin, are often used in identifying individual whales, as they are unique to each animal, similar to fingerprints in humans. The largest of these excrescences (callosities) is located on the anterior-most portion of the head and is referred to as the "bonnet." Other excrescences are on the upper edge of the lower jaw, behind the blowhole, and above the eye.
Eubalaena australis is on average between 16 and 18 meters long at maturity, males being slightly shorter than females. It has a rotund appearance, a very large girth relative to the length, with an enormous head (approximately 1/3 the body length). Southern right whales do not have any dorsal fins, nor do they have the grooved throat that is typical of the balaenopterids. The flippers are also broad and relatively short.
Another distinguishing physical feature of southern right whales is the blowhole. The exterior of the blow hole is well-partitioned, resulting in a V-shaped exhaust of condensation and water vapor. Furthermore, uncharacteristic of balaenopterids, southern right whales have a well-developed dermis without fat, whereas most balaenopterids lack a dermis (Cummings 1985).
Range mass: 36000 to 73000 kg.
Average mass: 49000 kg.
Range length: 16 to 18 m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Southern right whales are polygamous, having up to seven males per one female. Courtship and copulation is described as being tender and graceful (Cummings 1985). The duration of courting bouts varies, but usually lasts for an hour or two, after which the males and females separate from one another. There seems to be no animosity between males mating with the same female, which is quite unusual for mammals. It is believed that this passive behavior implies intra-uterine sperm competition.
Mating System: polygynous
Southern right whales, so named because they were historically considered the "right" whale to catch, reach reproductive maturity at approximately ten years of age. The gestation period ordinarily lasts for one year, and lactation continues for four to six months. Calves, which are born weighing 1000-1500 kg and are five to six meters long, grow at a rate of 3 cm per day.
Southern right whales mate and calve between 20 and 30° S and mostly in protected bays during the months of June to November.
Breeding season: Southern right whales mate and calve during the months of June to November.
Average number of offspring: 1.
Average gestation period: 12 months.
Range weaning age: 4 to 6 months.
Average age at sexual or reproductive maturity (female): 10 years.
Average age at sexual or reproductive maturity (male): 10 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average birth mass: 910000 g.
Average gestation period: 365 days.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (female)
Sex: female: 3285 days.
