THE DIFFERENT BREEDS OF DOLPHINS

By Jennifer mores

BOTTLENOSE DOLPHINS LIVE IN GROUPS TYPICALLY OF 10–30 MEMBERS, CALLED PODS, BUT GROUP SIZE VARIES FROM SINGLE INDIVIDUALS UP TO MORE THAN 1,000. THEIR DIETS CONSIST MAINLY OF FORAGE FISH. DOLPHINS OFTEN WORK AS A TEAM TO HARVEST FISH SCHOOLS, BUT THEY ALSO HUNT INDIVIDUALLY. DOLPHINS SEARCH FOR PREY PRIMARILY USING ECHOLOCATION, WHICH IS SIMILAR TO SONAR. THEY EMIT CLICKING SOUNDS AND LISTEN FOR THE RETURN ECHO'S TO DETERMINE THE LOCATION AND SHAPE OF NEARBY ITEMS, INCLUDING POTENTIAL PREY. BOTTLENOSE DOLPHINS ALSO USE SOUND FOR COMMUNICATION, INCLUDING SQUEAKS AND WHISTLES EMITTED FROM THE BLOWHOLE AND SOUNDS EMITTED THROUGH BODY LANGUAGE, SUCH AS LEAPING FROM THE WATER AND SLAPPING THEIR TAILS ON THE WATER SURFACE

The bottle nose Dolphin

THE SPINNER DOLPHIN

The spinner dolphin lives in nearly all tropical and subtropical waters between 40°N and 40°S.The species primarily inhabits coastal waters, islands, or banks. However, in the eastern tropical Pacific, dolphins live far from shore. Spinner dolphin may use different habitats depending on the season.

The spinner dolphin feeds mainly on small mesopelagic fish, squids, and sergestid shrimps, and will dive 200-300 m to feed on them. Spinner dolphins of Hawaii are nocturnal feeder and forage in deep scattering layers, which contain many species. The dwarf spinner dolphin may eat mostly on benthic fish in reefs and shallow water.[6] Off Oahu, Hawaii, spinner dolphins forage at night and cooperatively herd their prey into highly dense patches.[14] They swim around a circle of prey and a pair may swim through it to make a catch. Spinner dolphins are in turn preyed on by sharks. Other possible predators include the killer whale, the false killer whale, the pygmy killer whale and the short-finned pilot whale. They are also susceptible to parasites, both external ones like barnacles and remoras, and internal ones, like nematodes, trematodes, cestodes and acanthocephalans.