Toothed whale
From Wikipedia, the free encyclopedia
Toothed
whales
Fossil range: Latest Eocene - Recent
Bottlenose Dolphin
Scientific classification
Kingdom:
|
Animalia
|
Phylum:
|
Chordata
|
Class:
|
Mammalia
|
Order:
|
Cetacea
|
Suborder:
|
Odontoceti
Flower,
1869
|
The toothed
whales (systematic name Odontoceti) form a suborder of the
cetaceans. As the name suggests, the suborder is characterized by having teeth
(rather than baleen as do animals in the other suborder of cetaceans,
Mysticeti). Toothed whales are active hunters, feeding on fish, squid, and in
some cases marine mammals.
Anatomy
Toothed whales have a
single blowhole on the top of the head (while the baleen whales possess two of them).
The nostrils are not fused; one of them has become dominant over the other.
As an adaptation for their
echolocation, toothed whale skulls have become asymmetric. Their brains are
relatively big, although real growth didn't occur before their echolocation
started to evolve. Toothed whales' brains have a poor connection between the
two hemispheres. Toothed whales have an organ called the melon on their head,
which is used as a lens to focus their sound waves. Vocal chords are not
present; their sounds are produced in the blowhole system instead. Toothed
whales have lost their sense of smell, as well as their saliva glands.
Except for the Sperm Whale,
most toothed whales are smaller than the baleen whales. The teeth differ
considerably between the species. They may be numerous, with some dolphins
bearing over 100 teeth in their jaws. At the other extreme are the Narwhal with
its single long tusk and the almost toothless beaked whales with bizarre teeth
only in males. Not all species are believed to use their teeth for feeding. For
instance, the Sperm Whale likely uses its teeth for aggression and showmanship.
Behaviour
Vocals
Vocalizations are of great
importance for toothed whales. They maintain a broad variety of calls to
communicate, but also are capable of using ultrasound for echolocation.
Movement
Most toothed whales swim
rapidly. The smaller species occasionally ride waves, such as the bow waves of
ships. Dolphins can be frequently encountered this way. They are also famous
for their acrobatic breaching from the water, e.g. the Spinner Dolphin.
Social
behaviour
Generally, toothed whales
live in groups of up to a dozen animals. These groups, called pods or schools,
occasionally merge to form "superpods", aggregations of up to
thousands of whales. Toothed whales are capable of complex interactions, such
as cooperative hunting. In captivity, some species display a high potential for
learning; for this reason they are considered being among the most intelligent
animals.
Human
impact
The Sperm Whale has been
hunted commercially for a long time (see whaling). While small whales
like the Pilot Whale today are still being pursued, the main threat for most
species is accidental capture in fishing nets.
Keeping small whales
(mostly Bottlenose Dolphins, Orcas, or Belugas) in captivity is a great
attraction for ocean parks and zoos. However, it is controversial because of
thee marine mammals' need for large spaces.
Taxonomy
- Suborder Odontoceti: toothed whales
- Family Delphinidae: oceanic dolphins
- Genus Cephalorhynchus
- Commerson's Dolphin, Cephalorhynchus
commersonii'
- Chilean Dolphin, Cephalorhynchus
eutropia
- Heaviside's Dolphin, Cephalorhynchus
heavisidii'
- Hector's Dolphin, Cephalorhynchus
hectori
- Genus Steno
- Rough-toothed Dolphin, Steno bredanensis
- Genus Sousa
- Atlantic Humpback Dolphin, Sousa
teuszi
- Indian Humpback Dolphin, Sousa plumbea
- Chinese White Dolphin, Sousa chinensis
- Genus Sotalia
- Tucuxi, Sotalia
fluviatilis
- Genus Tursiops
- Bottlenose Dolphin, Tursiops truncatus
- Indian Ocean Bottlenose Dolphin, Tursiops
aduncus
- Genus Stenella
- Pantropical Spotted Dolphin, Stenella
attenuata
- Atlantic Spotted Dolphin, Stenella
frontalis
- Spinner Dolphin, Stenella longirostris
- Clymene Dolphin, Stenella clymene
- Striped Dolphin, Stenella coeruleoalba
- Genus Delphinus
- Short-beaked Common Dolphin, Delphinus
delphis
- Long-beaked Common Dolphin, Delphinus
capensis
- (Arabian Common Dolphin, Delphinus
tropicalis)
- Genus Lagenodelphis
- Fraser's Dolphin, Lagenodelphis hosei
- Genus Lagenorhynchus
- White-beaked Dolphin, Lagenorhynchus
albirostris
- Atlantic White-sided Dolphin, Lagenorhynchus
acutus
- Pacific White-sided Dolphin, Lagenorhynchus
obliquidens
- Dusky Dolphin, Lagenorhynchus obscurus
- Black-chinned Dolphin, Lagenorhynchus
australis
- Hourglass Dolphin, Lagenorhynchus
cruciger
- Genus Lissodelphis
- Northern Right Whale Dolphin, Lissodelphis
borealis
- Southern Right Whale Dolphin, Lissodelphis
peronii
- Genus Grampus
- Risso's Dolphin, Grampus
griseus
- Genus Peponocephala
- Melon-headed Whale, Peponocephala
electra
- Genus Feresa
- Pygmy Killer Whale, Feresa attenuata
- Genus Pseudorca
- False Killer Whale, Pseudorca
crassidens
- Genus Orcinus
- Orca (Killer Whale), Orcinus orca
- Genus Globicephala
- Long-finned Pilot Whale, Globicephala
melas
- Short-finned Pilot Whale, Globicephala
macrorhyncus
- Genus Orcaella
- Irrawaddy Dolphin, Orcaella
brevirostris
- Australian Snubfin Dolphin, Orcaella
heinsohni
- Genus Monodon
- Narwhal, Monodon monoceros
- Genus Delphinapterus
- Beluga, Delphinapterus leucas
- Family Phocoenidae: Porpoises
- Genus Neophocaena
- Finless Porpoise, Neophocaena
phocaenoides
- Genus Phocoena
- Harbour Porpoise, Phocoena
phocaena
- Vaquita, Phocoena
sinus
- Spectacled
Porpoise, Phocoena dioptrica
- Burmeister's Porpoise, Phocoena
spinipinnis
- Genus Phocoenoides
- Dall's Porpoise, Phocoenoides
dalli
- Genus Physeter
- Sperm Whale, Physeter macrocephalus
- Genus Kogia
- Dwarf Sperm Whale, Kogia sima
- Pygmy Sperm Whale, Kogia breviceps
- Family Ziphidae: beaked whales
- Genus Ziphius
- Cuvier's Beaked Whale, Ziphius
cavirostris
- Genus Berardius, giant beaked
whales
- Arnoux's Beaked Whale, Berardius
arnuxii
- Baird's Beaked Whale (North Pacific
Bottlenose Whale), Berardius bairdii
- Genus Tasmacetus
- Tasman Beaked Whale (Shepherd's Beaked
Whale), Tasmacetus shepherdi
- Sub-family Hyperoodontidae
- Genus Indopacetus
- Indo-Pacific Beaked Whale (Longman's
Beaked Whale), Indopacetus pacificus
- Genus Hyperoodon
- Northern Bottlenose Whale, Hyperoodon
ampullatus
- Southern Bottlenose Whale, Hyperoodon
planifrons
- Genus Mesoplodon,
mesoplodont whales
- Hector's Beaked Whale, Mesoplodon
hectori
- True's Beaked Whale, Mesoplodon mirus
- Gervais' Beaked Whale, Mesoplodon
europaeus
- Sowerby's Beaked Whale, Mesoplodon
bidens
- Gray's Beaked Whale, Mesoplodon grayi
- Pygmy Beaked Whale, Mesoplodon peruvianus
- Andrew's Beaked Whale, Mesoplodon
bowdoini
- Bahamonde's Beaked Whale, Mesoplodon
bahamondi
- Hubbs' Beaked Whale, Mesoplodon
carlhubbsi
- Ginko-toothed Beaked Whale, Mesoplodon
ginkgodens
- Stejneger's Beaked Whale, Mesoplodon
stejnegeri
- Layard's Beaked Whale, Mesoplodon
layardii
- Blainville's Beaked Whale, Mesoplodon
densirostris
- Perrin's Beaked Whale, Mesoplodon
perrini
- Super-family Platanistoidea: river dolphins
- Genus Inia
- Amazon River Dolphin, Inia geoffrensis
- Genus Lipotes
- Chinese River Dolphin, Lipotes
vexillifer
- Genus Platanista
- Ganges and Indus River Dolphin, Platanista
gangetica
- Genus Pontoporia
- La Plata Dolphin, Pontoporia
blainvillei
Wikipedia
http://en.wikipedia.org/w/index.php?title=Toothed_whale&action=history
http://www.gnu.org/copyleft/fdl.html