Amazon River Dolphin

Amazon River Dolphin

Boto, Boutu, Pink river dolphin, Bufeo

Inia geoffrensis
Population size
Life Span
30 years
Top speed
km/h mph 
kg lbs 
m ft 

The Amazon river dolphin (Inia geoffrensis) is a species of toothed whale. It is the largest species of river dolphin, and it has one of the widest-ranging diets among toothed whales. The Amazon river dolphin has been treated with suspicion by local people. Moreover, it is the subject of numerous myths and tales. According to one of the stories, Amazon river dolphins become handsome men in order to seduce young women, coming to the water.


The Amazon river dolphin has very evident sexual dimorphism, with males measuring and weighing between 16% and 55% more than females, making it unique among river dolphins, where females are generally larger than males. The texture of the body is robust and strong but flexible. Unlike in oceanic dolphins, the cervical vertebrae are not fused, allowing the head to turn 90 degrees. 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. The pectoral fins are large and paddle-shaped. The length of its fins allows the animal to perform a circular movement, allowing for exceptional maneuverability to swim through the flooded forest but decreasing its speed. The body color varies with age. Newborns and the young have a dark grey tint, which in adolescence transforms into light grey, and in adults turns pink as a result of repeated abrasion of the skin surface. Males tend to be pinker than females due to more frequent trauma from intra-species aggression. The color of adults varies between solid and mottled pink and in some adults the dorsal surface is darker. It is believed that the difference in color depends on temperature, water transparency, and geographical location. Despite small eyes, the Amazon river dolphin seems to have good eyesight in and out of the water. Like other toothed whales, it has a melon, an organ that is used for biosonar. Breathing takes place every 30 to 110 seconds.




The Amazon River dolphin is a South American mammal, distributed across the drainage basins of the Orinoco and Amazon Rivers and primarily occurring in rivers and streams with slow currents. As the wet season comes, the water level increases, flooding surrounding forests. During this period, the dolphins usually leave the deeper streams to swim through the trees.

Amazon River Dolphin habitat map

Climate zones

Amazon River Dolphin habitat map
Amazon River Dolphin
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Habits and Lifestyle

The Amazon River dolphins are typically found solitarily as well as in pairs. However, there have been recorded dolphin groups, consisting of up to 15 individuals. The Botos are most active in the early morning and late evening. These animals are neither fast swimmers nor deep divers, often preferring to swim on the water surface. Spotting a boat in the water, these curious dolphins swim up in order to explore it. The Amazon River dolphins are highly communicative animals, sometimes interacting with other dolphin species. Rolling, lob tailing, and flipper waving are common behavior among these playful animals. Moreover, they frequently play with their logs as well as pull at underwater grass. Also, these dolphins can often be seen playing with turtles, fish, and other aquatic life forms.

Group name
Seasonal behavior

Diet and Nutrition

Amazon River dolphins are carnivores (piscivores). Their diet usually consists of crustaceans, fish, and crabs.

Mating Habits

11 months
1 calf
2-3 years

Currently, very little is known about the mating system of these animals. Thus, the dolphins were thought to be monogamous, but recent studies have discovered facts, indicating other types of mating behavior in this species. Males of these dolphins are noticeably larger than females. They display extremely aggressive behavior: because of biting and abrasion, male dolphins often damage their fins, flukes, and blowholes. On the other hand, tooth-raking leads to scarring. The reason for this behavior can be tough competition for mating rights, which brings us to the polygynous mating system. In the meantime, they are likely to practice polyandry and polygynandry - a mating system, where both males and females have a number of mates. The breeding period occurs from October to November, while the gestation period lasts approximately 11 months. The female dolphin normally yields a single baby with an interval of up to 5 years. As soon as the baby is born, the mother immediately helps the youngster to come to the water surface for air. The calf is nursed by its mother for about a year after birth, becoming independent within 2-3 years. Male dolphins are ready to mate at 7-12 years of age, whereas females start to breed when they are 6-10 years old.


Population threats

: Presently, one of the major threats to these animals' population is the continued development of the river systems, which are the natural habitat of these dolphins: they suffer from separation of their range into smaller sections due to hydroelectric or irrigation schemes, damming rivers. Feeding on aquatic animals, the dolphins compete with local fishermen. Moreover, the animals are threatened by the fishing process, during which they can accidentally be caught in fishing nets or injured because of collisions with boats and motors.

Population number

According to the IUCN Red List, the total population size of the Amazon river dolphin is unknown today, but there are estimated populations in certain areas. Thus, in the Amazon basin, there are 107 individuals in the Solimões River (Brazil), 346 individuals in the Amazon River bordering Peru and Colombia, around 260 individuals in the Mamirauá Lake system of Brazil, and 13.000 individuals in the Mamirauá Sustainable Development Reserve. The Orinoco basin holds 122 individuals in the Apuré River (Venezuela), 14-15 individuals in the Orinoco River (Venezuela), and 8 individuals in the Casiquiare River (Venezuela). Currently, this species is classified as Data Deficient (DD) on the IUCN Red List.

Ecological niche

Amazon River dolphins have an important role as predators of the river, and prey on a range of fish species, thus controlling their populations.

Fun Facts for Kids

  • The Amazon River dolphin has a very long beak, which can contain up to 140 teeth.
  • The body of the animal is extremely flexible, helping the dolphin swim even through some very tight areas. The animal is also able to swim upside down: according to some experts, this position promotes better vision, given that the chubby cheeks of the dolphin are an obstacle to seeing downward while the animal is upright.
  • Due to living in highly murky waters with low visibility, these dolphins have small eyes and low vision.
  • As the rainy season comes, the Amazon River dolphins move to ponds and lakes, since the rivers are flooded.
  • They use a wide variety of whistles and clicks as a form of communication.
  • Not only these highly intelligent animals are capable of identifying potential dangers, related to humans, but they also learn to avoid these threats.
  • When hunting, these dolphins use the echolocation technique: they send out sounds that pass through the water, bouncing from objects, located in front of them and returning to the animal, providing information about the type, size, and speed of the potential prey.

Coloring Pages


1. Amazon River Dolphin Wikipedia article -
2. Amazon River Dolphin on The IUCN Red List site -

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