Mundo Azul

The Amazon River dolphin or boto is the largest river dolphin, weighing up to 180 kg (400 lb) with a length up to 2.6 m (8.5'). Most adult botos are pink, although some have a darker back or are partially gray. Although the boto's eyes appear small and inconspicuous, they are actually, in the skull, as large as those of marine dolphins. Thus the boto can see well. On the other hand, it can also rely on its sonar as it swims through a murky flooded forest. Utilizing its flexible neck, as it swims, a boto turns its head from side to side, sounding its way through the maze of drowned branches with a series of pulsed clicks at frequencies up to 170 kilohertz. Its bulbous forehead ends in a long, tube-shaped beak bearing sensory bristles that allow it to feel for food in a river’s depths. The pectoral fins are broad and paddle-like; the flukes are broad and triangular; and it lacks a prominent dorsal fin, possessing instead a low ridge along the back. It is believed that the boto's pink color comes from capillaries close to the surface of the skin that give it a rosy flush. Learn more about the boto’s natural history

Distribution:
The boto occurs throughout much of the Amazon and Orinoco watersheds, being found almost everywhere it can physically reach without venturing into marine waters. The principal limits to its distribution seem to be impassable rapids, waterfalls, and very small or shallow rivers. Its current distribution may be little different from that in pre-colonial settlement times: in the Orinoco River system, including the Apure and Meta Rivers, upstream as far as the rapids at Puerto Ayacucho; and throughout most of the Amazon basin (below an elevation of about 100 m (330')) plus the upper Rio Madeira drainage (above the Teotonio rapids) in Bolivia, where it is confined to the Rio Mamoré and its main branch the Rio Iténez (= Rio Guaporé), including lower reaches of their larger tributaries (at an elevation of 100 - 300 m (330 - 990')). It is found at water temperatures from 23 - 30 deg C (73 - 86 deg F).

Countries where the boto is currently found: Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela. (Amazon and Orinoco River basins)

Conservation Status:
The boto has benefited in many parts of the Amazon from legends that associate it with supernatural powers. It is believed that the spirits of drowned persons enter the bodies of botos, and that these animals change into handsome young men. Consequently there has been no direct hunting of this dolphin.

IUCN Status:

1994: Vulnerable
1996 - 2004: Vulnerable (Criteria: A1cd) (IUCN 2004)

The boto is vulnerable to human-induced habitat changes and suffers some incidental mortality in fisheries, but it has not yet been depleted to anything like the extent of its Asian counterparts, such as the baiji, the Ganges River dolphin, and the Indus River dolphin. Threats include bycatch in fisheries; hydroelectric development; deforestation; and pollution from agriculture, industry and mining. In Peru there are several reports of botos being poisoned by fishermen in and near the Pacaya Samiria Reserve who see them as competitors for fish. Another probably important problem for the botos survival is the increasing overfishing of rainforest rivers. Consecuently the river dolphin population is most dense where little fishing occurs (inside the Pacaya Samiria Reserve) and much lower in rivers which are heavily fished (outside the reserve). Read more

What Mundo Azul does in order to protect the Amazon River Dolphins.
There are no current population estimates for the Amazon River dolphins in Peru. The latest counts in some rivers within the protected area are from the mid-nineties and might not be valid anymore. Therefore Mundo Azul is in process of launching a long term population study of Amazon River dolphins and Tucuxis (the second dolphin species in the Amazon basin). We will be using photo-identification and transect counts. Only if we know the actual population and their trends in different rivers we can design specific conservation strategies and initiate programs with the local people. The study will be volunteer-based.

Read more about the botos natural history