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Family: Delphinidae
Genus: Steno
Species: S. bredanensis (Lesson, 1828)
Named for the rough surface that forms near the crowns of their teeth, these animals are further distinguished by the smooth slope of their faces from beak to forehead; in the typical bottlenose dolphin the demarcation is far more prominent. The rough-toothed dolphin’s compact spindle-shaped body is clearly built for speed; some rough-tooth dolphins can attain speeds in excess of 15 mph (24kph). Infrequently, rough-toothed dolphins have been kept in captivity in both Japan and Hawaii, where their behavior suggests they possess greater intelligence than do other marine mammals kept in captivity. One Hawaiian specimen, named “Poko”, rewarded for developing new behavior patterns on his own, displayed an array of dolphin creativity including swimming at the surface upside-down with its tail raised out of the water.
Physical Description: Unique among the beaked dolphins in its lack of a discernible demarcation line between the beak and forehead.
Color: Unusual mixture of gray, white, and pink multicolored blotches. Dark gray dorsally including the flippers and flukes. Beak and belly are white to the rear of the anus.
Fins and Flukes: A large, falcate dorsal fin is located on the mid-back region. Flippers are well developed and rounded at their tips. Flukes are small, rounded at the tips, with a well-defined median notch.
Length and Weight: This dolphin reaches 7.5 to 9 ft (2.3 to 2.7 m) and 350 lb (160 kg).
Teeth: 20 to 27 fairly large, conical teeth with vertically wrinkled crowns are found in each side of the upper and lower jaws.
Feeding: Known to feed on small fish, pelagic octopus, and squid.
Breathing and Diving: No reliable information.
Mating and Breeding: Very little is known. However, maturity occurs at 11 years of age and maximum longevity is 32 years.
Herding: Normally 10 to 20 or more are normal, but herds of several hundred have been reported. They often associate with pilot whales, spinner dolphins, bottlenose dolphins and pantropical spotted dolphins.
Distribution: Distributed throughout temperate seas of the Atlantic, Pacific and Indian oceans.
Migration: No information available
Natural History Notes: A rough-toothed dolphin at Sea Life Park in Hawaii mated with a bottlenose dolphin which gave birth to a healthy calf with characteristics of both species. Rough-toothed dolphins are avid bow-wave riders.
ROUGH-TOOTHED DOLPHIN DISTRIBUTION
