Taxonomical List

Marine mammals are a diverse group of roughly 120 species of mammal that are primarily ocean-dwelling or depend on the ocean for food. They include the cetaceans (whales, dolphins, and porpoises), the sirenians (manatees and dugong), the pinnipeds (true seals, eared seals and walrus), several otters (the sea otter and marine otter) and the polar bear.

Marine mammals evolved from land dwelling ancestors and share several adaptive features for life at sea such as generally large size, hydrodynamic body shapes, modified appendages and various thermoregulatory adaptations. Different species are, however, adapted to marine life to varying degrees. The most fully adapted are the cetaceans and the sirenians, whose entire life cycle takes place under water, whereas the other groups spend at least some time on land.

Despite the fact that marine mammals are highly recognizable charismatic megafauna, many populations are vulnerable or endangered due to a history of commercial exploitation for blubber, meat, ivory and fur. Most species are currently protected from commercial exploitation.

The order Cetacea includes whales, dolphins and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal," was more general. Cetology is the branch of marine science associated with the study of cetaceans.

Cetaceans are the mammals most fully adapted to aquatic life. Their body is fusiform (spindle-shaped). The forelimbs are modified into flippers. The tiny hindlimbs are vestigial; they do not attach to the backbone and are hidden within the body. The tail has horizontal flukes. Cetaceans are nearly hairless, and are insulated by a thick layer of blubber. As a group, Cetaceans are noted for their high intelligence.

The order Cetacea contains ninety species, all marine except for five species of freshwater dolphins. The order is divided into two suborders, Mysticeti (baleen whales) and Odontoceti (toothed whales, which includes dolphins and porpoises). In India we find 30 species of cetaceans and one species in the Order Sirenia.

Please note that the records in our database have species names as identified in the respective sources unless misidentifications have been reported. The current understanding is that there are no specimens to support the idea that there are Fin, Minke and Sei whales in the Northern Indian Ocean. It should also be noted that the taxonomy of the smaller delphinids in the region is still evolving.


Order CETACEA - Whales, Dolphins & Propoises
Suborder ODONTOCETI - Toothed Whales
Family DELPHINIDAE - Marine Dolphins
Family PHOCOENIDAE - Porpoises
Family PHYSETERIDAE - Sperm Whales
Family ZIPHIIDAE - Beaked Whales
Suborder MYSTICETI - Baleen Whales
Family DUGONGIDAE - Dugong


* According to the current understanding of distribution Fin, Sei and Minke whales are not present in the Northern Indian ocean.