They have one of the widest-ranging diets among toothed whales, and feed on up to 53 different species of fish, such as croakers, catfish, tetras and piranhas.

In addition, a 2014 study identifies a third species in the Araguaia-Tocantins basin,[18] but this designation is not recognized by any international organization and the Committee on Taxonomy of the Society for Marine Mammalogy suggests this analysis is not persuasive.

Inia geoffrensis boliviensis[7] has populations in the upper reaches of the Madeira River, upstream of the rapids of Teotonio, in Bolivia.

[21] The flukes are broad and triangular, and the dorsal fin, which is keel-shaped, is short in height but very long, extending from the middle of the body to the caudal region.

[22] Life expectancy of the Amazon river dolphin in the wild is unknown, but in captivity, the longevity of healthy individuals has been recorded at between 10 and 30 years.

There is significant segregation during the rainy season, with males occupying the river channels, while females and their offspring are located in flooded areas.

However, dolphins in captivity may not show the same behavior that they do in their natural environment, where they have been reported to hold the oars of fishermen, rub against boats, pluck underwater plants, and play with sticks, logs, clay, turtles, snakes, and fish.

When they surface, the tips of the snout, melon and dorsal fins appear simultaneously, the tail rarely showing before diving.

[7] Adult males have been observed carrying objects in their mouths such as branches or other floating vegetation, or balls of hardened clay.

Males often have a significant degree of damage in the dorsal, caudal, and pectoral fins, as well as the blowhole, due to bites and abrasions.

As the water level begins to decrease, the density of food sources in flooded areas increases due to loss of space, providing enough energy for infants to meet the high demands required for growth.

The most frequently consumed fish belong to the families Sciaenidae (croakers), Cichlidae (cichlids), Characidae (characins and tetras), and Serrasalmidae (pacus, piranhas and silver dollars).

[31] The dolphin's dentition allows it to access shells of river turtles (such as Podocnemis sextuberculata) and freshwater crabs (such as Poppiana argentiniana).

Sometimes, they associate with the distantly related tucuxi (Sotalia fluviatilis), and giant otters (Pteronura brasiliensis) to hunt in a coordinated manner, by gathering and attacking fish stocks at the same time.

For each click produced a multitude of echoes are likely to return to the echolocating animal almost on top of each other which makes object discrimination difficult.

A series of rapids and waterfalls in the Madeira River have isolated one population, recognized as the subspecies I. g. boliviensis, in the southern part of the Amazon basin in Bolivia.

In a study conducted in the stretch of the Amazon called Solimões River, with a length of 1,200 kilometres (750 mi) between the cities of Manaus and Tabatinga, a total of 332 individuals was sighted ± 55 per inspection.

In another study, on a stretch of 120 kilometres (75 mi) at the confluence of Colombia, Brazil and Peru, 345 individuals with a density of 4.8 per square km in the tributaries around the islands.

[9] In the Pacaya-Samiria National Reserve, Peru, photo-identification is used to recognize individuals based on pigmentation patterns, scars and abnormalities in the beak.

[19] Research in 2011 concluded that photo-identification by skilled operatives using high-quality digital equipment could be a useful tool in monitoring population size, movements and social patterns.

[38][39] One of these ecosystems is a floodplain, or a várzea forest, and is home to a large number of fish species which are an essential resource for human consumption.

[29] The abundance of distinct fish species lures the Amazon River dolphin into the várzea areas of high water occurrences during the seasonal flooding.

[43] In addition to attracting predators such as the Amazon river dolphin, these high-water occurrences are an ideal location to draw in the local fisheries.

[51] Increasing demand for the piracatinga has created a market for distribution of the Amazon river dolphin carcasses to be used as bait throughout these regions.

[40] The data do not fully represent the actual overall number of deaths of the Amazon river dolphins, whether accidental or intentional, because a variety of factors make it extremely complicated to record and medically examine all the carcasses.

[40][45][48] Scavenger species feed upon the carcasses, and the complexity of the river currents make it nearly impossible to locate all of the dead animals.

[40] More importantly, the local fishermen do not report these deaths out of fear that a legal course of action will be taken against them,[40] as the Amazon river dolphin and other cetaceans are protected under a Brazilian federal law prohibiting any takes, harassments, and kills of the species.

[54][55] In 2008, the International Whaling Commission (IWC) expressed concern for captured botos for use as bait in the Central Amazon, which is an emerging problem that has spread on a large scale.

[57] In September 2012, Bolivian President Evo Morales enacted a law to protect the dolphin and declared it a national treasure.

According to the pink Amazon river dolphin myth, it is said that this creature takes form of a human and seduces men and women to the Underworld of Encante.