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Rough-toothed dolphin
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Common Name:
Rough-toothed Dolphin
Class: Mammalia
Order: Cetacea
Family: Delphinidae
Genus: Steno
Species: Steno bredadensis
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Taxonomy/Description
Rough-toothed dolphins belong to the Mammalian Order Cetacea, in the
suborder Odontoceti. All toothed whales belong to the suborder
Odontoceti, which is Latin for "toothed whales". This dolphin
belongs to the oceanic dolphin family, Delphinidae. Other members of
this family include the killer whale, long-beaked common dolphin,
and pilot whale. The rough-toothed dolphin's scientific name is
Steno bredadensis. The generic name, Steno, is Greek for “narrow”,
referring to the narrow head of the rough-toothed dolphin, which
lacks a clearly defined melon and snout. The specific name,
bredadensis, is named for Monsieur Van Breda of Ghent. Van Breda
sent a sketch of the animal's skull to the French naturalist Georges
Cuvier (1769-1832). Cuvier, a comparative anatomist and natural
history professor, attributed the sketch to a previously identified
species. Fortunately for Van Breda, a French zoologist, Rene
Primevere Lesson (1794-1849) identified the new species, naming the
species in honor of Van Breda. The animal’s common name of
“rough-toothed” refers to ridges on the enamel of the teeth.
The rough-toothed dolphin differs from other species of dolphin by
the shape of its head. No distinct definition exists between the
melon and rostrum, giving the animal’s head a cone-shaped
appearance. The body is gray in color, with lighter shades on the
belly and sides. The lips are usually white. Adults grow 7-8.5 in
length, weighing 300-350lbs.
Habitat/Diet
Although the exact geographic distribution of the rough-toothed
dolphin is not well documented, it has been observed in tropical and
subtropical waters of the Mediterranean and Caribbean Seas, and the
Pacific, Atlantic, and Indian Oceans. Deep, open ocean, far offshore
is the common habitat of the rough-toothed dolphins, where they hunt
a variety of fish, squid, mollusks, and octopi.
Behavior/Reproduction
Rough-toothed dolphins usually form family groups of 10-50
individuals. Little is known about there breeding habits and social
structure. Bow riding is not common. These dolphins “skim”, which is
swimming just beneath the surface with only their dorsal fins
exposed. Associations with other dolphin species are not unusual,
including bottlenose, spotted, and spinner dolphins. Birth length is
about three feet. Females reach sexual maturity at 10 years of age,
while males mature sexually at 14 years.
Conservation
Rough-toothed dolphins are harpooned in Japan and West Africa.
Entanglement in fishing gear is also a threat. Necessary alterations
of these nets now allow dolphins to escape. Other human activities
endanger dolphins, such as pollution and habitat encroachment. The
worldwide population is unknown.
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