|
Common Name: Beaked Whales
Class: Mammalia
Order: Cetacea
Family:
Ziphiidae
Genus: Six
genera
Species: 19
species
|
Blainville's
beaked whale, Mesoplodon densirostris |
Beaked Whales: Family Ziphiidae
The
whales of the family Ziphiidae belong to the Mammalian Order Cetacea,
in the suborder Odontoceti. All toothed whales belong to the
suborder Odontoceti, which is Latin for "toothed whales". Ziphiidae
is Latin, derived from the Greek xiphos, meaning "sword".
This refers to the prominent beaks of these animals.
Blainville's beaked
whale, Mesoplodon densirostris
Ziphiidae is the second largest cetacean family, after Delphinidae.
Members of this family are characterized by a prominent beak,
sometimes with a bulging forehead. Two visible teeth protruding
from the lower jaw are evident in most species. Other
non-functional teeth are present in some species, with the exception
of Shepherd's beaked whale, which has small functional teeth. All
species lack upper teeth, with the exception of Gray's beaked whale
and Shepherd's beaked whale. Heavy scarring suggests the large
teeth of the lower jaw are used aggressively. Very little data has
been collected on these animals, with some species actually never
having been observed alive. Beaked whales feed on deep ocean fish
and cephalopods, diving to extremely deep depths to hunt for their
prey. Adaptations for deep diving include small dorsal fins, sound
receiving channels and tunnels present in the upper beak to receive
sound, and recesses in the body walls acting as "flipper pockets"
which reduce the drag of pectoral fins. The flukes of beaked whales
also differ from other cetaceans, lacking a central notch. The
tendency of beaked whales to dive deeply frequently prevents
researchers from adequately studying their behavior.
Blainville's beaked
whale, Mesoplodon densirostris
The
general difficulty of studying these animals has prevented any
reliable population estimates. Due to the overall lack of
sightings, it is assumed that most species are quite rare.
Strandings of unknown causes have been the main sources of
descriptive data for most species. The northern bottlenose whale
was once hunted for the spermaceti oil found in its melon, but has
been protected since 1973. A possible threat to beaked whales is
the use of low frequency sonar used by the United States Navy.
Further studies are needed to confirm its affect on ziphiids, as
well as other cetacean species.
There
are six genera within the family Ziphiidae, containing a total of 19
species. The genera and species are:
Genus: Ziphius
The generic name
Ziphius, is Latin, derived from the Greek xiphos, meaning
"sword". This refers to the beak of this animal.
Cuvier's beaked
whale Ziphius cavirostris
The specific name,
cavirostris, is derived from the Latin words cavus,
meaning "hollow", and rostrum, meaning "snout". This refers
to the hollow formation at the base of this species' snout. The
common name is named for Baron Georges Cuvier (1769-1832), a French
naturalist and comparative anatomist. This species inhabits
temperate and tropical ocean waters worldwide. The whales seem to
move north to temperate waters during the summer. Sightings have
occurred as far north as Alaska. Two large teeth are present in
males. These teeth are not visible in females. Adults are grayish
in color, occasionally with darker dorsal coloration and white
splotches on the head and back. Length at maturity is about 20ft.
Some data suggests adults weigh between 2.5-3 tons. Females are
generally larger than males. A distinct calving season has not been
concluded. Gestation lasts about 12 months. Calves are 6-9ft in
length. Lifespan estimates range from 36-62 years.
Genus: Hyperoodon
The generic name
Hyperoodon, is derived from the Greek words hyperoe,
meaning "the upper mouth or palate", and odontos, meaning
"tooth". However, this name is misleading, considering whales of
this genus have only two teeth on their lower jaw. In 1788, a
French zoologist, Count de Lacepede (1756-1825), misidentified small
bumps on the palate of stranded beaked whale as teeth, giving rise
to this name. The two species belonging to this genus are similar
in physical size and coloration. Adult males reach lengths of about
30 feet, while females grow to about 25 feet in length. Young males
and females do not have the very prominent bulging forehead, which
contains a large oil filled organ similar to the spermaceti organ
found in sperm whales. Males have a pair of protruding teeth on the
lower jaw, while both sexes have vestigial teeth in the upper and
lower jaws. Calving seasons for both species appear to peak in the
spring. Gestation lasts about 12 months. Newborn calves are 9-10ft
in length. Males achieve sexual maturity at 7-11 years, while
females sexually mature at 8-12 years. The estimated lifespan is at
least 37 years.
Northern
bottlenose whale Hyperoodon ampullatus
The specific name,
ampullatus, is Latin for "flask or bottle". This describes the
animal's head, which is characterized by narrow snout protruding
from a well-defined, large, fleshy melon. The range of species
includes the North Atlantic and occasionally the Mediterranean Sea.
Southern
bottlenose whale Hyperoodon planifrons
The specific name,
planifrons, is derived from the Latin words planitia,
meaning "flat", and frons, meaning "forehead". This refers
to the large, flat forehead of this species. The range of this
species includes the southern portions of the Atlantic Ocean,
Pacific Ocean, and Indian Ocean, inhabiting the coastal areas of
Australia, New Zealand, South Africa, and Antarctica.
Genus: Tasmacetus
The generic name
Tasmacetus, probably means "Tasman whale", referring to the
geographic range of this species, which includes the southern
Pacific Ocean surrounding Australia, New Zealand, and Tasmania.
Shepherd's beaked
whale or Tasman whale Tasmacetus shepherdi
The specific name,
shepherdi, is named for G. Shepherd, a curator at the Wanganui
Alexander Museum in New Zealand. Shepherd collected a nearly
complete skeleton of the animal while at the museum. Descriptive
data of this species is based on four specimens, three males and one
female. It appears the two large teeth of the anterior lower jaw
are present only in males, for they had not erupted in the single
female specimen. Shepherd's beaked whale has small functional teeth
in addition to the large protruding pair. Unlike all other beaked
whales, with the exception of Gray's beaked whale, Shepherd's beaked
whale has teeth on the upper jaw. The diet of this species includes
species of small deep ocean fish and crustaceans. Adults grow to
lengths of 18-21ft.
Genus: Berardius
The generic name
Berardius, is named for Auguste Berard, the commander of a
French naval station at Banks Peninsula in New Zealand during the.
He was also the captain of the ship responsible for the delivery of
the first Arnoux's beaked whale skull of to Georges Louis Duvernoy
(1777-1855), a French zoologist and assistant of Georges Cuvier.
Duvernoy examined and named the specimen. The two species of this
genus are not specifically distinct. They are separated
geographically. Arnoux's beaked whale and Baird's beaked whale are
the largest beaked whales species. Members of this genus have the
most symmetrical skulls of all odontocetes. Two large teeth
protrude from the lower jaw of both species. Deep sea fish,
octopus, squid and crustaceans compose their diet.
Arnoux's beaked
whale Berardius arnuxii
The specific name,
arnuxii, is named for M. Arnoux, a French surgeon responsible
for presenting a skull of the species to the Paris Museum of Natural
History in 1846. Georges Louis Duvernoy was responsible for naming
the skull. Unfortunately, he misspelled "Arnoux", omitting the "o"
from the name. Arnoux's beaked whale inhabits the ocean waters of
the Antarctic pack ice, the South Pacific, southern Indian Ocean,
and South Atlantic. This species is smaller than Baird's beaked
whale, generally growing no longer than 30ft in length.
Baird's beaked
whale Berardius bairdii
The specific name,
bairdii, is named for Spencer Fullerton Baird (1823-1887), an
American naturalist and secretary at the Smithsonian Institution.
Baird's beaked whale is found in the throughout the northern
Pacific, as far north as the Bering Sea and as far south as Baja
California. Adults grow to lengths of 36-40ft, and weigh about 12
tons. Females are slightly larger than males. Migrations during
the summer and autumn to the continental slope from the open ocean
have been recorded. Mating occurs in late fall, with calving
peaking in mid-spring. The gestation period is the longest of all
cetaceans, at about 17 months. Lifespan estimates range from 54-84
years.
Genus: Indopacetus
The generic name,
Indopacetus, probably means "Indopacific whale", referring to
the geographic range of this species.
Indo-Pacific
beaked whale Indopacetus pacificus
The specific name,
pacificus, means "belonging to the Pacific", referring to the
Pacific Ocean. Descriptive data of this species is based on six
specimens, none of which were alive when obtained. Based on the
locations of the specimens, researchers believe this whale's range
includes the subtropical waters of the southern Pacific Ocean and
Indian Ocean. No reliable data regarding its physical description,
diet, and behavior exists.
Genus: Mesoplodon
The generic name
Mesoplodon, is derived from the Greek words mesos,
meaning "middle", oplon, meaning "tool or weapon", and
odon, meaning tooth. Collectively, this means "armed with a
tooth in the middle of the jaw", referring to the placement of the
teeth in this genera.
Sowerby's beaked whale
Mesoplodon bidens
The specific name,
bidens, is Latin for "two teeth". This refers to the only two
teeth this species has, which are in the middle of the lower jaw.
The common name is named for James Sowerby (1757-1822), an English
naturalist and artist, who first to described the whale in 1804.
The primary range of this species includes the temperate waters of
the North Atlantic, possibly the Mediterranean Sea and Gulf of
Mexico. Body coloration is bluish gray dorsally, fading to a
lighter color ventrally. Adults grow to a length of about 15 feet.
Andrews' beaked whale
Mesoplodon bowdoini
The specific name,
bowdoini, is named for George Bowdoin, a trustee of the American
Museum of Natural History during the early 20th century. The common
name, Andrews', is probably named for Roy Chapman Andrews
(1884-1960), a world famous explorer and director of the American
Museum of Natural History. Andrews' was a marine mammalogist, as
well as a paleontologist, also discovering the first dinosaur eggs
during an expedition to Mongolia. The range of this species
includes the subtropical waters surrounding Australia, New Zealand,
and Tasmania. Body coloration is dark gray, while the head and beak
are white. Males are larger than females, reaching lengths of about
15 feet. Females generally grow to 12-13ft in length.
Hubb's beaked whale
Mesoplodon carlhubbsi
The specific name,
carlhubbsi, is named after Carl Hubbs (1894-1979), an American
ichthyologist and the first to describe the whale. The range of
this species includes the temperate waters of the North Pacific.
Males have small functional teeth in addition to the two prominent
large teeth. Body coloration is dark gray, with white patches on
the head. Adults range in size from 15-20ft in length.
Blainville's beaked
whale Mesoplodon densirostris
The specific name,
densirostris, is derived from the Latin words densus,
meaning "dense", and rostrum, meaning "snout". The upper
mouth of this species is composed of the densest bone of all known
animals. The bone has a mass of 2.7 grams per cubic centimeter.
This means it is four times denser than the tympanic bulla of the
fin whale, which was previously thought to contain the densest bone,
and 50% denser than any other mammalian bone. Tiny channels
throughout the bone make it extremely brittle, which suggests whales
of this species do not ram one another. Some researchers have
proposed these tunnels are necessary for receiving acoustical
signals used while echolocating. The common name, Blainville, is
named for Henri Marie Ducrotay de Blainville (1777-1850), a French
zoologist and anatomist. Blainville became the chair of anatomy and
zoology in the Faculty of Sciences at Paris with the help of Georges
Cuvier. The range of this species includes the tropical and
subtropical waters of all oceans. Color ranges from gray to brown
dorsally, with a lighter underside. Adults range in size from
10-20ft in length.
Blainville's beaked
whale, Mesoplodon densirostris
Gervais' beaked whale
Mesoplodon europaeus
The specific name,
europaeus, means "belonging to Europe", probably referring to
the range of this species. The common name is named for the Paul
Gervais (1816-1879), a French paleontologist and colleague of George
Cuvier and Henri Marie Ducrotay de Blainville. This species' range
includes the temperate and tropical waters of the North Atlantic
Ocean. Body coloration is dark gray dorsally, fading to a lighter
shade ventrally. Adults range in size from 13-17ft in length.
Ginkgo-toothed beaked
whale Mesoplodon ginkgodens
The specific name,
ginkgodens, is derived from the Latin word dens, meaning
"tooth", and the word ginkgo, a type of tree. This refers to
the similarity in shape of the ginkgo-toothed beaked whale's tooth
and that of a ginkgo tree's leaf. The range of this species
includes the subtropical and tropical waters of the Pacific Ocean
and Indian Ocean. The two protruding teeth of the ginkgo-toothed
whale are shaped like leaves of the ginkgo tree. Body coloration is
characterized by a dark gray background with a spattering of white
spots. Adults reach lengths of 14-15ft.
Gray's beaked whale
Mesoplodon grayi
The specific name,
grayi, is named for a former director of the British Museum,
John E. Gray (1800-1875). Gray described at least three species of
beaked whale during his career. He died one year before the naming
of this specimen, which occurred in 1876. The range of this species
includes the temperate and subtropical waters of the southern
hemisphere. Interestingly, one confirmed sighting of this whale in
the northern hemisphere, off the coast of the Netherlands, exists.
This species has teeth on the upper jaw, unlike all other beaked
whale species, with the exception of Shepherd's beaked whale. Body
coloration is dark gray dorsally, fading to a lighter shade
ventrally. The beak is white in color. Adults grow to lengths of
18-20ft.
Hector's beaked whale
Mesoplodon hectori
The specific name,
hectori, is named for James Hector (1834-1907), a curator of the
Wellington Museum in New Zealand. Information regarding this
species stems from 20 specimens, which were found from southern
California, Argentina, the Falkland Islands, South Africa, New
Zealand, and Tasmania. These locations suggest this species' range
includes the tropical and subtropical waters of the Pacific Ocean,
Indian Ocean, and Atlantic Ocean. Body coloration is dark gray
dorsally, fading to a lighter shade ventrally. Adults grow to about
13 feet in length.
Strap-toothed whale or
Layard's beaked whale Mesoplodon layardii
The specific name,
layardii, is named for Edgar Leopold Layard (1824-1900), a
curator of the South American Museum. Layard was the first to
describe this whale species. Strap-toothed refers to the shape of
the two teeth of the lower jaw, which protrude only from male
whales, even while the mouth is closed. In fact, these teeth prevent
males from opening their mouths greater than 5-6 inches. This
whale's range includes the subtropical waters of the southern
Pacific Ocean and southern Atlantic Ocean. Body coloration is dark
gray dorsally, fading to a lighter shade ventrally. Light splotches
are present on the head and beak. Adults reach lengths of 15-20ft.
True's beaked whale
Mesoplodon mirus
The specific name,
mirus, is Latin for "wonderful or extraordinary". This refers
to the placement of two teeth at the very tip of the whale's lower
jaw. The common name is named for the F.W. True, an American
zoologist and whale researcher of the late 19th century. This
species' range includes the temperate waters of the Atlantic Ocean
and Indian Ocean. Body coloration is gray dorsally, fading to a
lighter shade ventrally. Adults grow to about 15 feet in length.
Pygmy beaked whale
Mesoplodon
peruvianus
The specific name,
peruvianus, means "belonging to Peru". The first specimen was
discovered off the coast of Peru in 1991. Information regarding
this species stems from 12 specimens, which were found in Baja
California and Peru. These locations suggest this species' range
includes the tropical waters of the western Pacific Ocean. Body
coloration is gray dorsally, fading to a lighter shade ventrally.
Adults grow to lengths of 10-12ft. This is the smallest species of
beaked whale.
Stejneger's beaked whale
Mesoplodon stejnegeri
The specific name,
stejnegeri, is named for Leonhard Hess Stejneger (1851-1943), a
Norwegian zoologist working under Spencer Baird at the Smithsonian
Institution. He eventually became Head Curator of Biology at the
Museum. Interestingly, Stejneger wrote a biography of George
Wilhelm Steller (1709-1746), a German zoologist responsible for
studying and exploring life of the northern Pacific Ocean. Steller
discovered species of marine mammals unknown to science, including
Steller's sea cow and Steller's sea lion. This biography brought
recognition to Steller's work, which had not been published. The
primary range of this species includes the temperate waters of the
North Pacific. Body coloration is dark gray dorsally, fading to a
lighter shade ventrally. Adults reach lengths of 9-16ft.
