Hyperoodon planifronssouthern bottlenose whale

Geographic Range

Hyperoodon planifrons is found in the waters off of Australia, New Zealand, Brazil, Argentina, Tierra del Fuego, the Falkland Islands, South Georgia, the South Orkney Islands, South Africa, and the Pacific and Indian ocean sectors of Antarctica. Southern bottlenose whales have also been sighted near Sri Lanka.

(Nowak 1997, Tinker 1988)

Habitat

Hyperoodon planifrons mainly stays in cooler waters and approaches the ice packs of Antarctica during the summer. For the winter months, southern bottlenose whales migrate towards tropic waters (Minasian et al. 1984).

Physical Description

Hyperoodon planifrons individuals grow to about 8 meters in length. Sexual dimorphism is seen in this species, with the males averaging a length of 7.5 meters and the females averaging only 6.5 meters. Body mass has been estimated at 6 to 8 tons. The body of H. planifrons is cylindrical in shape and tapers toward the tail in the last 1/3 of its length. The tail flukes are wide and lack the notched center that is often seen in other cetaceans. Southern bottlenose whales have short, distinct beaks protruding from an inflated forehead or melon. In females and young males, the forehead slopes smoothly into the beak. In older males, the forehead rises abruptly from the beak. The dorsal fin of H.planifrons is located 2/3 of the body length from the head, measures between 30 to 40 cm, and is sickle-shaped with a blunt tip. This whale's flippers are small, short, and also blunt-tipped.

Male H. planifrons have one pair of short, conical teeth which are situated at the tip of the lower jaw. Teeth are not found in the upper jaw. The teeth of females are either smaller or do not emerge at all. Rows of vestigial teeth are often present in the lower and upper jaw.

Southern bottlenose whales are a brownish-grey color on the head, back, dorsal fin, flippers, and tail . This color is paler on the belly, throat, and sides. However, coloration becomes lighter with age. Calves are a grayish-brown to black color, while older whales are completely yellowish-white in color.

(Tinker 1988, Nowak 1997, Baker 1983, Minasian et al. 1984)

Reproduction

Calving in Hyperoodon planifrons occurs in the spring or summer. The young measure about 3 meters at birth. Very little information is known about the reproductive cycle of H. planifrons, but it probably resembles the cycle of its close relative, Hyperoodon ampullatus, northern bottlenose whales. In that species, females probably give birth every 2 years, with a gestation period of 12 months. Weaning of young takes place after one year. Sexual maturity of female bottlenose whales is reached between the ages of 8-12, and in males, between 7-11 years of age. The life span of H. planifrons is at least 37 years.

(Tinker 1988, Nowak 1997)

Behavior

Southern bottlenose whales generally stay well out to sea and are found in waters over 1,000 meters deep. Herds of H. planifrons are small, ranging from 2 to 12. Hyperoodon planifrons travel and dive together as a very compact group, and dives may last up to 45 minutes. A frequent behavior of H. planifrons is diving under ice and raising the beak clear of the water on the last surfacing before sounding. Interactions or contact with other species is uncommon for H. planifrons. Little information is available about their mode of communication, but it is probably quite similar to H. ampullatus. A variety of sounds have been recorded for that species, which include a series of clicks and whistles used for echolocation and communication, respectively.

(Nowak 1997, Minasian et al. 1984, Ponganis and Kooyman 1995)

Communication and Perception

Food Habits

Hyperoodon planifrons is known to feed primarily on squid, and most likely, on fishes (Tinker 1988).

  • Animal Foods
  • fish
  • mollusks

Economic Importance for Humans: Positive

There is very little economic importance attached to this species. Hyperoodon planifrons has never been subjected to systematic whaling, unlike its close relative, Hyperoodon ampullatus.

(Tinker 1988, Minasian et al. 1984)

Economic Importance for Humans: Negative

There are no adverse effects of H. planifrons.

Conservation Status

IUCN lists Hyperoodon planifrons as conservation dependent. This designation means that this species would fall into a higher category of threat or be driven to the point of extinction, if it were not for conservation efforts (Baillie and Groombridge 1996).

Other Comments

Hyperoodon planifrons may also be called the Antarctic bottlenose whale.

Ziphiids have a pair of grooves on their throat that converge anteriorly to form a V pattern at the chin.

A large bottlenose whale can yield up to 200 kg of spermati oil, which is used in making ointments and fine, smokeless candles. Furthermore, it can yield up to 2,000 kg of blubber oil, which is a base of many skin creams and cosmetics.

Based on geological evidence, Hyperoodon ampullatus and Hyperoodon planifrons probably diverged as recently as 15,000 years ago. There are fossil records of ziphiid whales from the lower Miocene Epoch to the Holocene Epoch.

(Mead 1989, Tinker 1988, Nowak, 1997)

Contributors

Colette Hendricks (author), University of Michigan-Ann Arbor.

Glossary

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.

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.

carnivore

an animal that mainly eats meat

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.

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).

molluscivore

eats mollusks, members of Phylum Mollusca

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.

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.

References

Baillie, J. and B. Groombridge, ed. 1996. IUCN Red List of Threatened Animals. The IUCN Species Survival Comission.

Baker, A. 1983. Whales and Dolphins of New Zealand and Australia. Vistoria University Press, Victoria.

Minasian, S., K. Balcomb, III, and L. Foster. 1984. The World's Whales: The Complete Illustrated Guide. W.W. Norton & Company, New York.

Nowak, R. 1997. Walker's Mammals of the World. http://www.press.jhu.edu/books/walkers_mammals_of_the_world/prep.html

Ponganis, P. and G. Kooyman. 1995. Multiple Sightings of Arnoux's Beaked Whales Along the Victoria Land Coast. Marine Mammal Science 11(2):247-250.

Tinker, S. 1988. Whales of the World. E.J. Brill, New York.