Different Types of Dolphins

The aquatic mammals commonly known as dolphins consist of almost 40 different species, which are spread between two different genus in the suborder Odontoceti, or toothed whales. The Oceanic dolphins are members of the family Delphinidae, with the rarer freshwater varieties belonging to the Platanistidae family. Several dolphin species also are misnamed and commonly are called whales.

  1. Lagenorhynchus Dolphins (White-Sided Dolphins)

    • With six different members, the Lagenorhynchus genus is the largest group of dolphins. Most of the species in this group are known for having a less prominent forehead and a shorter beak, or rostrum, giving them a more rounded facial appearance. These dolphins also tend to be dark gray in color with some form of white patterning. This genus includes the Atlantic and Pacific white-sided dolphins, as well as the white-beaked, hourglass, Dusky and Peales varieties.

    Stenella Dolphins (Spotted, Spinner or Striped Dolphins)

    • The second most common genus is Stenella, which groups together five dolphin species. With the longer beak and more prominent forehead, these species are more similar to most people's image of dolphins. The name Stenella actually means narrow in Latin and refers to the pointed beaks of this group. The members of this group include the Pantropical and Atlantic spotted dolphins, as well as the Atlantic spinner, Pantropical spinner and the striped varieties.

    Fake Whales

    • Several species commonly known as whales actually are dolphins, such as the long finned pilot whale, which is in fact the second largest dolphin species, and its close cousin, the short-finned pilot whale. The massive, predatory orca is the largest dolphin species. Its close cousin, the false killer whale, as well as the pygmy killer whale and the melon-headed whale also are species of dolphin.

    River Dolphins

    • Worldwide, four species of river dolphin exist, including the Yangtze, Ganges, Amazon and La Plata dolphins, and are found in areas of South America, China and India. River dolphins tend to be more broad-bodied than the streamlined oceanic species and have a longer beak. All of the river dwelling species are endangered mainly due to the damming and redirecting of river ecosystems.

    Other Dolphins

    • Many of the world's dolphin species have their own genus of which they are the only member. Coming in a wide range of sizes, all oceanic dolphins as a rule have long, streamlined bodies suited to fast swimming. The most commonly recognized species probably is the bottle-nosed dolphin, which often is used in marine displays at aquariums. Two of the planet's other dolphin species live in salt and fresh water, the tucuxi and the irrawaddy.