There are five known species of river dolphins
in the world. Unlike their relatives, the oceanic dolphins, river dolphins live in fresh water
. There are four families
that are all grouped together under the superfamily Platanistoidea
. The families are:
River dolphins are some of the most endangered
of all the world's cetaceans
. Due to habitat loss, hunting by humans, and naturally low numbers, they are extremely vulnerable to extinction
. Also many river dolphins also possess very poor eyesight (some are considered blind) which can lead to unfortunate encounters with humans or manmade objects (boats or fishing nets for example).
Some dolphin species can live in marine or riverine environments. The Tucuxi, for example, is equally at home in both ecotypes. However these are not classified in the Platanistoidea superfamily and are not regarded therefore as true river dolphins.
For more information, see the articles on the individual species