Dolphins are cetaceans that live in marine and continental waters. They are very intelligent animals with an enormous capacity for communication with each other. Freshwater dolphins inhabit rivers in Asia and South America.
These types of dolphins are highly threatened, since humans invade their habitat, which negatively affects their reproduction. River pollution, dams, and boat traffic is an adverse factor for the existence of freshwater dolphins.
If you continue reading this article you will learn about the different types of freshwater dolphins, their habitat and customs.
Pink dolphin
Probably the best known of the freshwater dolphins is the pink dolphin, or boto. Its scientific name is: Inia geoffrensis, and it is very widespread in the basins of the Amazon and Orinoco rivers. This dolphin is the largest of the freshwater dolphins, reaching almost three meters in length and weighing up to 185 kg. It has 25-29 teeth in its jaws.
The pink dolphin, unlike marine dolphins, does not have fused cervical vertebrae. Which allows you to turn your neck in all directions. The boto is a very playful animal that is not afraid of humans, approaching them to pry.
What gives it its name is the pinkish color of its skin when it reaches adulthood. These dolphins feed on fish, including piranhas. They also eat turtles and crabs. On the other hand, the predators of the pink dolphin are the bull shark when it makes river incursions up the rivers. Caimans, anacondas and jaguars also attack these beautiful cetaceans.
Pollution by heavy metals, pulp mills and other human industries are a great danger to the species. It is a protected animal.
Bolivian dolphin and Araguaria river dolphin
The Bolivian Dolphin
Its scientific name is Inia boliviensis and it is smaller than the pink one but has a greater number of teeth in the hemimandible, 31-35 in total. It is threatened.
The Araguaria river dolphin
This dolphin, scientifically known as Inia araguaiaensis, is a species of freshwater dolphin discovered in 2014It is the smallest in the South American continent, and has the fewest number of teeth in its hemi-jaw, totaling 24-28. It is also an endangered species.
The River Plate Dolphin
This dolphin commonly called tonina or franciscana in Argentina and Uruguay, inhabits the magnificent estuary of the Plata River. Its scientific name is Pontoporia blainvillei. This cetacean of up to 1.80 meters can live in fresh or s alt water indistinctly. Its average weight is about 50 Kg.
The color of this dolphin is a greyish-brown, lighter on the belly. The bottlenose dolphin is a protected cetacean, because it is considered a vulnerable species.
Ganges Dolphin
In the Ganges, Brahmaputra, Meghna, Karnaphuli, Sangu and other rivers of India, Nepal, Bangladesh and Bhutan, there is a dolphin that can reach up to 2, 60 meters. Females are even larger.
The Gangetic dolphin, Platanista gangetica, also known as the gangetic dolphin or shushuk, has small populations and is threatened in the same way as its South American congeners. This cetacean is blind because it lacks a lens It moves through echolocation (waves emitted by the dolphin, bouncing off objects and configuring a mental map of their shape and movement in the brain of the cetacean).
Indus Dolphin
The Indus dolphin, Platanista minor, is quite similar to the Ganges dolphin. It is also known as bhulan, or blind Indus dolphin. Its size does not exceed 2.5 meters. This cetacean is also blind and uses the same echolocation system as its conspecific from the Ganges.
The organ housed in the heads of both species that emits these ultrasounds is called phonic lips. It is an endangered species.
If you are passionate about the world of marine animals in general, we encourage you to also discover the marine animals of Baja California as well as the largest sea fish in the world.
