The Amazon River dolphins are the largest freshwater dolphins in the world!
The Amazon River dolphin is also known as the pink dolphin or Boto in Portuguese.
There is taxonomic uncertainty about how many species should be recognised in the genus, two subspecies are currently recognised: I. g. boliviensis, the Bolivian Bufeo, and I. g. geoffrensis, the common Boto. The fact that these dolphins inhabit several river basins in addition to the Amazon also adds to the taxonomic uncertainty with further research needed to clarify the taxonomy of Inia.
There is limited information on this species population structure and population size and trends throughout their range, with estimates varying from a few dozen to a few thousand.
The threats to this species include: accidental bycatch, deliberate killing for fish bait or predator control, damming of rivers, and environmental pollution. The use of the Amazon River dolphin as bait in Piracatinga (catfish) fisheries in Brazil is probably the most serious human-caused conflict. Studies have shown that dams fragment and isolate dolphin populations and are likely to degrade the downstream habitat.
Whilst markets around Amazonian cities and Brazil display products from “Boto” molecular studies have revealed that these products are mainly from domestic animals, or other species of dolphin caught in nets and sold.
Brazil has established a National Action Plan for the Conservation of Small Cetaceans which lists I. geoffrensis as an endangered species. This plan is intended to reduce human impacts and increase knowledge on small cetaceans in Brazil. Additionally, a South American River Dolphins Action Plan and national action plans has been produced for Bolivia, Ecuador, and Colombia. Action plans for Peru and Venezuela are in preparation.
- Order: Cetartiodactyla
- Family: Iniidae
- Population: Unknown
- Trend: decreasing
- Size: Up to 2.5m (?)
The Amazon River dolphin occurs throughout the Amazon and Orinoco river basins in Brazil, Bolivia, Colombia, Ecuador, Peru, and Venezuela.
Habitat and Ecology
The biology and ecology of this species is strongly related to the seasonal variation in water levels. The Amazon River dolphin swims into flooded forests in the high-water season in search of prey.
Sexual segregation is common in females with dependent calves spending more time inside the flooded forest, in lakes and small tributaries during the high-water season – which have slower currents, and an abundance of fish, while most adult males occur in the main rivers.
During low water seasons in the main river the Amazon River dolphin in seen within 150m of the river bank with lower densities in the centre of large rivers.