Mesoplodon bidensSowerby's beaked whale

Ge­o­graphic Range

Sowerby's beaked whales are found in tem­per­ate to sub arc­tic wa­ters in the east­ern and west­ern North At­lantic. They are found around the British Isles and are known to occur from New­found­land to Mass­a­chu­setts. Sowerby's beaked whales occur as far north as Labrador in the west and in the Nor­we­gian Sea in the east, south­ern limit is thought to be some­where be­tween 33ºN and 41ºN. ("MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006a; ; Bar­rett and Mac­don­ald, 1993; Car­war­dine, 2002; Clapham, et al., 2002; Culik, 2003; Mot­tet, 2003; Ruff and Wil­son, 1999; "MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006a; Bar­rett and Mac­don­ald, 1993; Car­war­dine, 2002; Clapham, et al., 2002; Culik, 2003; Mot­tet, 2003; Ruff and Wil­son, 1999)

Habi­tat

Sowerby's beaked whales are found in cool to warm tem­per­ate off­shore wa­ters of the North At­lantic Ocean. They are usu­ally ob­served in open water and most often seen in areas were depths range from 198 to 1524 m. (Car­war­dine, 2002; Clapham, et al., 2002; Mot­tet, 2003)

  • Range depth
    198 to 1524 m
    649.61 to 5000.00 ft

Phys­i­cal De­scrip­tion

Meso­plodon bidens is bluish grey to slate grey in color, with a lighter un­der­side, grey and white spots may be pre­sent on the body with lim­ited scar­ing. Meso­plodon bidens have a long slen­der beak that con­tains a pair of teeth mid­way up the lower jaw. They have a long think body, long flip­pers for the Meso­plodon fam­ily, and no notch in the fluke. The dor­sal fin is quite small with a rounded tip and may ap­pear fal­cate. Young M. bidens have a light blusih grey to white un­der­side, more promi­nant than in adults. ("MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006b; ; Car­war­dine, 2002; Clapham, et al., 2002; Culik, 2003; Mot­tet, 2003)

  • Sexual Dimorphism
  • male larger
  • Range mass
    1000 to 1300 kg
    2202.64 to 2863.44 lb
  • Range length
    5 to 5.5 m
    16.40 to 18.04 ft

Re­pro­duc­tion

Noth­ing is known about the mat­ing sys­tems of M. bidens. (Bar­rett and Mac­don­ald, 1993; Car­war­dine, 2002; Clapham, et al., 2002)

Lit­tle in known about gen­eral re­pro­duc­tive be­hav­ior of M. bidens. Mat­ing is thought to occur in late win­ter, with births late in spring and ges­ta­tion last­ing about 12 months. Young are about 2.4 to 2.7 me­ters in length and weigh about 185 kg. ("MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006b; Bar­rett and Mac­don­ald, 1993)

  • Breeding interval
    Breeding interval is not known for Sowerby's beaked whales.
  • Breeding season
    Mating is thought to occur in late winter.
  • Average number of offspring
    1
  • Average gestation period
    12 months

Sowerby's beaked whale fe­males pro­vide milk for their young and pro­tect them. There is no other avail­able in­for­ma­tion on parental in­vest­ment. ("MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006b; Bar­rett and Mac­don­ald, 1993; Car­war­dine, 2002; Clapham, et al., 2002; Culik, 2003; Mot­tet, 2003; Ruff and Wil­son, 1999)

  • Parental Investment
  • precocial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifes­pan/Longevity

The is no data on the lifes­pan in M. bidens. ("MarineBio.​org", 2006; Bar­rett and Mac­don­ald, 1993; Car­war­dine, 2002; Clapham, et al., 2002)

Be­hav­ior

When sur­fac­ing, Sowerby's beaked whales have been ob­served com­ing up at a steep angle with the head break­ing the sur­face first. They then take a se­ries of quick breaths (about 4 to 6) over a pe­riod of a minute. After a minute at the sur­face they take a longer dive for about ten to fif­teen min­utes, and may resur­face up to 800 me­ters away. They have been recorded to dive up to 28 min­utes. The blows of M. bidens are usu­ally in­vis­i­ble or fairly in­con­spic­u­ous. ("MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006b; Car­war­dine, 2002; Clapham, et al., 2002; Culik, 2003; Mot­tet, 2003)

Sowerby's beaked whales are so­cial an­i­mals, most often ob­served in pairs. Oc­ca­sion­ally they are seen in pods rang­ing from 3 to 10 in­di­vid­u­als. Sowerby's beaked whales stay clear of boats, so sight­ings are rare and most ob­ser­va­tions of these whales are from strand­ings. Sowerby's beaked whales often strand in pairs; some­times as many as six in­di­vid­u­als will stand to­gether. They are the most com­monly stranded species in the genus Meso­plodon. There are records of M. bidens strand­ings year round, ex­cept for the month of Feb­ru­ary. The high­est den­sity of strand­ings ap­pears to occur be­tween the months of July and Sep­tem­ber. (Bar­rett and Mac­don­ald, 1993; Car­war­dine, 2002; Clapham, et al., 2002; Culik, 2003; Mot­tet, 2003)

Home Range

There is no in­for­ma­tion on the home range of M. bidens.

Com­mu­ni­ca­tion and Per­cep­tion

A young an­i­mal, that was kept in a dol­phi­nar­ium for a few hours, was recorded using high fre­quency sound pulses to echolo­cate. (Bar­rett and Mac­don­ald, 1993)

Food Habits

The diet of Sowerby's beaked whales con­sists mostly of squid, oc­to­pus, and fish. A necropsy of one in­di­vid­ual showed stom­ach con­tents that in­cluded bot­tom-dwelling and deep water fish. ("MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006b; Car­war­dine, 2002; Clapham, et al., 2002; Culik, 2003; Mot­tet, 2003)

  • Animal Foods
  • fish
  • mollusks

Pre­da­tion

There is no in­for­ma­tion about pre­da­tion on Sowerby's beaked whales. Once they reach their adult size it is likely that they are pro­tected from much pre­da­tion. Killer whales and large sharks may tar­get Sowerby's beaked whales. ("MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006a; Bar­rett and Mac­don­ald, 1993; Car­war­dine, 2002; Clapham, et al., 2002; Culik, 2003; Mot­tet, 2003; Ruff and Wil­son, 1999)

Ecosys­tem Roles

Lit­tle is known about the role of Sowerby's beaked whales in the north­ern At­lantic ecosys­tem. They are un­doubt­edly preda­tors of ma­rine or­gan­isms. ("MarineBio.​org", 2006; Car­war­dine, 2002; Clapham, et al., 2002)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Sowerby's beaked whales were once in­fre­quently har­vested by Nor­we­gian whalers. They are no longer hunted ac­tively. (Clapham, et al., 2002)

  • Positive Impacts
  • food

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Sowerby's beaked whales are oc­ca­sion­ally caught in fish­ing gear, dam­ag­ing nets in the process. Ar­guably this is more trau­matic for the whales than fish­ing crews. (Clapham, et al., 2002; Culik, 2003)

Con­ser­va­tion Sta­tus

There is very lit­tle data on Sowerby's beaked whales. As a re­sult there is lit­tle in­for­ma­tion on pop­u­la­tion sizes, cur­rent or his­toric, to de­ter­mine con­ser­va­tion sta­tus. This species is rarely seen in the open ocean, most records are from strand­ings. ("MarineBio.​org", 2006; Bar­rett and Mac­don­ald, 1993; Car­war­dine, 2002; Clapham, et al., 2002; Ruff and Wil­son, 1999)

Other Com­ments

As with all beaked whales (Ziphi­idae) there is very lit­tle data on M. bidens. This species was the first of the beaked whales to be de­scribed. It was de­scribed by John Sowerby in 1804. ("MarineBio.​org", 2006; "Whale and Dol­phin Con­ser­va­tion So­ci­ety", 2006b; Car­war­dine, 2002; Clapham, et al., 2002)

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Rachel Mortensen (au­thor), Uni­ver­sity of Wis­con­sin-Stevens Point, Chris Yahnke (ed­i­tor, in­struc­tor), Uni­ver­sity of Wis­con­sin-Stevens Point.

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

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

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

diurnal
  1. active during the day, 2. lasting for one day.
echolocation

The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.

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.

food

A substance that provides both nutrients and energy to a living thing.

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.

nomadic

generally wanders from place to place, usually within a well-defined range.

pelagic

An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).

piscivore

an animal that mainly eats fish

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

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

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

visual

uses sight to communicate

viviparous

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

young precocial

young are relatively well-developed when born

Ref­er­ences

2006. "MarineBio.​org" (On-line). Meso­plodon bidens. Ac­cessed Oc­to­ber 22, 2006 at http://​marinebio.​org/​species.​asp?​id=334.

2006. "Whale and Dol­phin Con­ser­va­tion So­ci­ety" (On-line). Ac­cessed Oc­to­ber 22, 2006 at http://​www.​wdcs.​org/​dan/​publishing.​nsf/​allweb/​BBA6AFE5C70302F7802569CF00406D58.

2006. "Whale and Dol­phin Con­ser­va­tion So­ci­ety" (On-line). Sowerby's Beaked Whale Dis­tri­b­u­tion and Threats. Ac­cessed Oc­to­ber 22, 2006 at http://​www.​wdcs.​org/​dan/​publishing.​nsf/​allweb/​342DF2CCB12D2FD0802569CF00404FB9.

Bar­rett, P., D. Mac­don­ald. 1993. Prince­ton Field Guides: Mam­mals of Eu­rope. Prince­ton New Jer­sey: Prince­ton Uni­ver­sity Press.

Car­war­dine, M. 2002. Whales Dol­phins and Por­posies. New York City, New York: Dor­ling Kinder­s­ley.

Clapham, P., J. Pow­ell, R. Reeves, B. Stew­art. 2002. Na­tional Audubon So­ci­ety Guide to Ma­rine Mam­mals. New York: Al­fred A. Knopf.

Culik, B. 2003. "Con­ven­tion on Mi­gra­tory Species" (On-line). Ac­cessed Oc­to­ber 22, 2006 at http://​www.​cms.​int/​reports/​small_​cetaceans/​data/​m_​bidens/​m_​bidens.​htm.

Mot­tet, C. 2003. "Texas Ma­rine Mam­mal Stand­ing Net­work" (On-line). Ac­cessed Oc­to­ber 22, 2006 at http://​www.​sci.​tamucc.​edu/​tmmsn/​29Species/​sowerbysbeakedwhale.​html.

Ruff, S., D. Wil­son. 1999. The Smith­son­ian Book of North Amer­i­can Mam­mals. Wash­ing­ton D.C.: Smith­son­ian In­sti­tu­tion Press.