Rough-toothed dolphin
 

Common Name: Rough-toothed Dolphin
Class: Mammalia
Order: Cetacea
Family: Delphinidae
Genus: Steno
Species: Steno bredadensis
 



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.


 

Content provided by Canisius College students under the direction of Michael Noonan, PhD.