Eubalaena australissouthern right whale

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Geographic Range

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).

Habitat

While avoiding warm equatorial regions, southern right whales remain near continents and island masses.

Physical Description

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
    79295.15 to 160792.95 lb
  • Average mass
    49000 kg
    107929.52 lb
  • Range length
    16 to 18 m
    52.49 to 59.06 ft

Reproduction

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.

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 number of offspring
    1
    AnAge
  • Average gestation period
    12 months
  • Average gestation period
    365 days
    AnAge
  • Range weaning age
    4 to 6 months
  • Average age at sexual or reproductive maturity (female)
    10 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    3285 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    10 years

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    70 years
    AnAge

Behavior

Southern right whales migrate to the southern latitudes of their range during the summer months where plankton populations are more abundant, and migrate north during winter and spring.

They do so at a rate of 2.7 to 4.2 kilometers/hour over a 24-hour period for cow and calf pairs. In addition, Eubalaena australis have been observed at near-shore swimming speeds of up to 15+ km/hr (for only short distances), but are generally slow swimmers.

Eubalaena australis produce short, low frequency moans and pulses. Also heard, often below and above the water's surface, are the blows of the southern right whales. However, the most common sound produced is a belch-like utterance that averages 1.4 seconds long at a frequency of less than 500 Hz. These whales also produce simple moans in a narrow range of frequencies and complex moans that shift frequencies and overtones (Cummings 1985). Other sounds created by southern right whales are those caused by the slapping of theirs fins and tails, while rolling over at the surface of the water -- usually occuring during mating courtships.

In a common behavior among these whales, called "headstanding", they assume a vertical position and extend the flukes into the air, often rocking back and forth, for as long as two minutes at a time. Research initially indicated that this position was used for feeding on benthic organisms, however is more recently believed to be either a resting position or a courtship stimulus. Southern right whales are also commonly seen breeching -- turning in midair and falling into the water with the side or back of the body. This behavior may dislodge parasites from the whale's surface, but is also a display mechanism during mating (Cummings 1985).

Communication and Perception

Food Habits

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.

Economic Importance for Humans: Positive

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.

Economic Importance for Humans: Negative

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.

Conservation Status

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.

Other Comments

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).

Contributors

Julia Smith (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

filter-feeding

a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

planktivore

an animal that mainly eats plankton

polygynous

having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

zooplankton

animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)

References

Accessed November 16, 1999 at http://www.via-rs.com.br/iwcbr/frafrai.html.

Accessed November 16, 1999 at http://www.hermanus.co.za/whales/.

Accessed November 16, 1999 at http://www.biodiversity.environment.gov.au/plants/threaten/information/species/animals/mammals/Southern_Right_Whale/.

Ridgeway, S., R. Harrison. 1985. Handbook of Marine Mammals, Volume 3. San Diego, CA: Academic Press Limited.