Types of Dolphins

It’s ironic that oceanic dolphins are more popular than river dolphins, especially because it’s the latter who are in dire need of attention. In this particular article, we will shed light on different types of dolphins in a bid to make readers aware of the fact that the world of these cetaceans goes well beyond the bottlenose species.
Lost in translation!

Killer whales are actually dolphins and not whales. Long story short, the Spanish sailors used to call them ‘Matador de Ballenas‘, which can be loosely translated to killer of whales. The ‘of’ in that phrase, has since been lost in translation.

When we hear the word ‘dolphin’, what comes to mind is the endearing and highly intelligent bottlenose dolphin shown in movies and television shows. The fact though, is that there are 42 different species of dolphins, ranging from the Hector’s dolphin, which happens to be the smallest dolphin in the world, to the Orca or killer whale, which happens to be the largest of all dolphin species.

Different Types of Dolphins

The 42 extant dolphin species are grouped into 4 types, based on various factors, including which part of the world they are found in and what type of water they inhabit. So, we have dolphins that inhabit oceans, like the famous bottlenose dolphins and killer whales, as well as ones that inhabit freshwater sources, like the Amazon river dolphin and South Asian river dolphin. While the Amazon river dolphin is a New World species, the South Asian river dolphin is an Old World species.

In short, there is a great deal of diversity when it comes to the world of these marine mammals.

Of the four river dolphin species, the first three reside in freshwater rivers, while the La plata dolphin dwells in the salt-water estuary. Extant river dolphins do not bear much semblance to their oceanic cousins. Their beaks are extremely large, even forming one-fifth of the total body length in some species. They have extremely well-developed brains and short, broad flippers. Moreover, they are almost blind, which makes sense, considering that they live in muddy water and hence, do not need vision.

Porpoises (Family Phocoenidae)

Despite all the similarities, porpoises are different from dolphins. They are smaller and have short, blunt snouts. They are often referred to as small dolphins by sailors and fishermen. The six extant species of porpoises are …

» Burmeister’s porpoise (Phocoena spinipinnis)
» Dall’s porpoise (Phocoenoides dalli)
» Finless porpoise (Neophocaena phocaenoides)
» Harbor porpoise (Phocoena phocoena)
» Spectacled porpoise (Phocoena dioptrica)
» Vaquita porpoise (Phocoena sinus)

If they have not been able to emerge independently, it might have something to do with the fact that they have been overshadowed by dolphins, their popular cousins.

The Indo-Pacific humpback dolphin, Amazon river pink dolphin, and the Indus river dolphin are on the brink of extinction, while the Yangtze river dolphin (A.K.A. Baiji) has been declared functionally extinct. River dolphins in particular are at a greater risk because of river pollution, increasing river traffic, constructions of dams, destruction of tropical rainforests, etc. Oceanic dolphins too, have a whole lot of woes of their own; noise pollution resulting from marine transportation being one of them. Various volunteer programs and organizations have dedicated themselves to the noble cause of saving these dolphins, but then, the fact that we have neglected the species for so long means it won’t be an easy task.