Berardius bairdii

Geographic Range

Berardius bairdii have a limited range within the northern Pacific ocean. They can be found in waters near Japan and southern California and as far north as the Bering Sea. They prefer deeper water, beyond the 1000 meter line (Minasian, S.,K Balcomb, III and L Foster, 1984. Watson, L. 1981).

• Biogeographic Regions
• pacific ocean pacific ocean
  • native native

Habitat

From June to August, B. bairdii can be found in warm waters near Japan and California and near British Columbia in September. In the fall, the whales migrate north towards the Bering Sea and spend their winters in cold water near the Aleutian islands. This may be due to seasonal distribution of squid. They prefer deep water, beyond the 1000 meter line (Minasian,S.,K Balcomb, III and L Foster, 1984. Watson, L. 1981).

• Aquatic Biomes
• coastal coastal

Physical Description

The average length of B. bairdii is 10.3 meters for males and 11.2 meters for females. Calves are about 4.5 meters at birth. They are medium to large sized whales and often grouped with the great whales. They are the largest of the Ziphiidae family. Their bodies are long and cylindrical with a characteristic beak where the lower jaw extends about 10 centimeters beyond the tip of the the upper jaw. Their blow hole is low and wide. Their heads are angled backwards when they breathe so that their front teeth and beaks are visible (Minasian et al. 1984; Watson 1981).

B. bairdii have two pairs of teeth, the first pair protruding 9 centimeters from the extended lower jaw. The second pair is roughly 20 centimeters behind the first and grow to about 5 centimeters. The teeth of the female are slightly smaller than those of the male. B. bairdii are a blueish grey color, often with a brown tinge. Their undersides are usually lighter with three patches of white on the throat, between the flippers, and near the navel and anus. These spots range in size from barely visible to an almost continuous stripe across the belly. Two grooves run along the underside of the jaw in a wishbone shape. Females tend to be lighter in color than males, who often have tooth scars on their beaks. B. bairdii have trangular fins about 30 centimeters tall and set far back on the body (Minasian et al. 1984, Watson 1981).

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

Most B. bairdii reach sexual maturity when they are about 9.4 meters long for males and 10 meters long for females. They mate in mid-summer in warm waters near Japan and California. The gestation period is thought to be approximately ten months, though pregnancies of up to 17 months have been reported. Calves are born between late November and early May. A mother will usually produce one calf every three years. The average lifespan is about 70 years (Minasian,S.,K Balcomb, III and L Foster, 1984. Watson, L. 1981).

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Lifespan/Longevity

Behavior

B. bairdii travel in small groups ranging from 6-30 members. These breeding groups are led by one large male. The scars on the beaks and backs of males suggest aggression and rivalry for this leadership position (Watson, L. 1981).

They usually rise 3-4 times at 10-20 second intervals before diving for 20 minutes or longer. They have been known to stay underwater for over an hour. These whales are fairly elusive and shy of ships, though they sometimes bask at the surface until startled (Watson, L. 1981).

B. bairdii have natural parasites such as ship barnacles, acorn barnacles, and whale lice. Oval sucker scars caused by parasite crustaceans ( Livoneca ravnaudi ) can be seen on many individuals. They are sometimes found stranded (Watson, L. 1981).

• Key Behaviors
• natatorial natatorial
• motile motile
• social social
• dominance hierarchies dominance hierarchies

Communication and Perception

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

These whales are deep divers and feed most often on squid, particularly Gonatus fabricii . They also eat octopus, lobster, crab, rockfish, and herring. Occasionally they eat starfish and sea cucumbers (Watson, L. 1981).

• Primary Diet
• carnivore carnivore
  • molluscivore molluscivore

• Animal Foods
• fish
• mollusks
• aquatic crustaceans
• echinoderms

Economic Importance for Humans: Positive

These whales have been a long time resource for Japanese coastal whaling industries. In the 1950's, due to new fishing technologies, up to 382 whales were taken each year. With declining numbers and emphasis on other species, the number of B. bairdii caught has diminished (Watson, L. 1981).

Conservation Status

Other Comments

B. bairdii is very similar to a southern relative, B. arnuxxi . They may be geographically isolated populations of the same species, but the difference in size suggests that they each deserve species rank (Watson, L. 1981).

Additional Links

Encyclopedia of Life

Contributors

Barbara Lundrigan (author), Michigan State University, Allison Myers (author), Michigan State University.

References

Minasian, S., K. Balcomb, III, L. Foster. 1984. The World's Whales . U.S.: The Smithsonian Institute.

Watson, L. 1981. Sea Guide to Whales of the World . London: Hutchinson and Co..