Spotted Dolphin (Stenella attenuata)
Suborder: Odonticeti Family: Delphinidae
Common in Hawaiian waters.
Other known names:
White-spotted dolphin, Bridled dolphin, Spotter, Spotted porpoise, Slender-beaked dolphin
General description and habits:
There are two different forms of pantropical spotted dolphins; coastal and offshore. The coastal dolphins are larger with thicker beaks and more spots. Spotted dolphins sometimes don't have many spots and some of the spotted dolphins in Hawaii and the Gulf of Mexico aren't spotted at all. When they are born they have no spots, so its easy to confuse them with other dolphins such as the bottlenose. Pantropical spotted dolphins are very similar to Atlantic spotted dolphins. They have a dark gray cape on the top of their body, a lighter gray area along the middle of the body and a pale gray underside. They have light spots on their dark skin and dark spots on their light skin. Their beaks are long and thin with a dark patch on top that goes back in a stripe around the eye. They also have a dark stripe going from under their mouth to their flippers. Pantropical spotted dolphins have small flippers with pointed tips, sickle-shaped dorsal fins and a notch in their flukes that have pointed tips. They have 70-96 teeth in their upper jaw and 68-94 in their lower jaw. Adult pantropical spotted dolphins are between 1.7 and 2.4 meters (5ft 9in - 8ft) long. They are about 80 - 90cm (32-35in) at birth. The birth weight of pantropical spotted dolphins is not known, but adults weigh between 90 and 115kg (200-255lb). Like Atlantic spotted dolphins, pantropical spotted dolphins are very fast swimmers and enjoy leaping out of the water. They will often bow-ride, breach and lob-tail. They are likely to be shy of boats in areas where tuna fishing takes place, as they can get caught in the fishing nets. They live in large groups of up to 1000 individuals, though the coastal populations are more likely to be seen in smaller groups.
Identity Keys to use in the field:
Long, slender beak; no teeth visible; white "lips"; flippers, flukes and fin are dark; dark cape area on the back around the dorsal fin; lighter under-side; sickle-shaped dorsal fin; tall dorsal fin; black patch around eye; fast active swimmer; often bow-rides; frequently seen in very large groups
Fish, squid and sometimes crustaceans
Pantropical spotted dolphins live mainly in tropical or warm waters, and are found in the Atlantic, Pacific and Indian Oceans. They are often seen around islands and there are populations in the eastern tropical Pacific, the western North Atlantic, the Gulf of Mexico and around Hawaii.
Hunting, entanglement in fishing nets, environmental changes
Some pantropical spotted dolphins develop so many spots that the background color cannot be seen. The top of their bodies becomes very pale with all the spots and they are nicknamed "Silverbacks".