The rough-toothed dolphin (Steno bredanensis) is a medium-to-large member of the family Delphinidae. It is an open‑ocean species typically found in deep, warm and tropical seas around the globe and is classified among the oceanic dolphins.

Description

Adults usually measure about 2–3 metres in length. The species has a slim, elongated body and a long, narrow beak. Coloration is generally a brownish or slate gray on the back, shading to a lighter belly; some individuals show a darker "saddle" or cape behind the dorsal fin. The common name refers to the texture of the teeth, which can appear worn or coarse in older animals.

Range and habitat

Rough-toothed dolphins have a circumtropical distribution, recorded in the Atlantic, Pacific and Indian Oceans. They prefer offshore waters over continental slopes, seamounts and other deep-water features, although they may occur nearer shore around islands and in some continental shelf areas.

Behavior and diet

These dolphins are social, typically seen in groups that range from a few individuals to several dozen; larger aggregations are reported but less common. Their diet consists mainly of fish and cephalopods. Like many delphinids, they use echolocation to locate prey and are active swimmers that sometimes ride bow waves or approach vessels.

Reproduction and lifespan

Females give birth to a single calf after a gestation period typical for delphinids. Calving intervals and age at maturity vary by region and are influenced by environmental conditions. Lifespan in the wild is not precisely known but is comparable to other medium-sized dolphins.

Conservation and human interactions

On a global scale the rough-toothed dolphin is not currently regarded as highly threatened, although local populations can be affected by bycatch in fisheries, marine pollution, and habitat changes. They have been involved in occasional mass strandings. The species is difficult to maintain in captivity, and few individuals have been kept long-term.

Notes

  • Taxonomy: family Delphinidae, genus Steno.
  • Habitat preference: deep, warm offshore waters, often near productive features such as slopes and seamounts.
  • Diet: primarily fish and squid.