One of around five species of river dolphin, the iconic pink Amazon River dolphin features in many myths and legends of indigenous Amazon communities.
Learn all about these captivating creatures in this fascinating expert guide from Whale and Dolphin Conversation.
What does the Amazon River dolphin look like?
Amazon River dolphins look very different to marine dolphins. Firstly, they’re pink! Born grey, adult Amazon River dolphins turn pink or pinkish-grey as they mature, with males being both bigger and pinker than females.
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That’s not the only difference, though. With low ridge-like dorsal fins, long, skinny snouts, plump bodies, chubby cheeks and round, bulbous foreheads, they have developed a unique look of their own. Babies are born a bluish-grey colour and they get pinker as they age.
Their flippers are large, paddle-like and have a wide range of motion. Their bodies are very flexible and capable of twisting laterally and they can swim backwards. Their cheeks are wide and protruding and the melon (head) is not compact and firm, like other dolphins, but protuberant and soft, capable of changing its shape by voluntary muscle contraction and during echolocation.
Mature males are pinker than females, which could be to do with their penchant for fighting. As wounds heal, they are covered with pink scar tissue, which eventually replaces their grey skin.
Their tail flukes are often ragged along the edges, as a result of interactions with each other.Males are both longer and heavier than females.
How big are Amazon River dolphins?
Male Amazon River dolphins are about 2.5m in length, while females are just a little shorter at around 2.25m. Males also weigh more at 207kg, while females weigh between 141 -153.5kg depending on whether they are pregnant or not
Calves are just 0.8m in length and weigh 12kg
How well can Amazon River dolphins see?
Despite their fairly small eyes, Amazon River dolphins don’t struggle to see and, in fact, their eyesight is very good, both below and above the water’s surface. Aided by their unfused neck vertebrae, they can get a good look at their underwater worlds by turning their heads in all directions and checking things out from every angle.
Where do Amazon River dolphins live?
Despite the understandable connection people often make with dolphins and the open ocean, Amazon River dolphins only live in fresh water – often thousands of kilometres from the sea.
Living in huge rivers, small tributaries, lakes, flooded forests and submerged grasslands, Amazon River dolphins can be found in seven countries: Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru and Venezuela. These include resident populations throughout the Amazon and Orinoco river systems, as well as in the Araguaia River in Brazil.
What do Amazon River dolphins eat?
Amazon River dolphins 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. They also consume other animals such as river turtles, aquatic frogs, and freshwater crabs.
How do they track their prey?
Amazon River dolphins have lithe, manoeuvrable bodies. They are dexterous swimmers andcan easily weave their way through submerged trees and shrubs to find food. Amazon River dolphins are natural underwater gymnasts, swimming backwards, upside down and pivoting, assisted by large, paddle-shaped flippers that they can circle independently of each other. This is helpful when prey is quick and prone to take refuge in hard-to-reach places.
Do they use teamwork when feeding?
It’s difficult to be sure about all their hunting activities. Underwater observations are extremely difficult in the Amazon, as the turbid river water makes it murky with no clear view below the surface.
How many teeth do Amazon River dolphins have?
They have around 25 to 28 pairs of long, slender teeth to each side of both jaws. They differ in shape and length for grabbing and crushing prey.
Amazon River dolphins are the only dolphins who have heterodont dentition – the equivalent of molar teeth – much as we do.
They use these teeth to crunch up their food before swallowing. This enables them to eat hard prey such as river crabs and small turtles. They can cut large catfish and big, armoured fish into smaller pieces before swallowing them. (This is significant as all other dolphins have only conical teeth.)
How fast can Amazon River dolphins swim?
The Amazon River dolphin is a relatively slow swimmer compared to its ocean-dwelling counterparts. Adult pink river dolphins typically swim at speeds between 8-13km per hour, with occasional bursts of up to 24 km per hour over short distances – perhaps in pursuit of a tasty snack!
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Do they come to the surface for long?
They are not deep divers and spend a lot of time near or at the surface.
Do Amazon River dolphins form pods, like their marine cousins?
Amazon River dolphins tend to live in small pods. During high water season, mothers and calves and immature Amazon River dolphins stay together in flooded areas, such as lakes and smaller rivers in the flooded forest. Males will travel further afield in the main rivers looking for opportunities to mate with other groups of females.
When do Amazon river dolphins mate?
As water levels fall the dolphins leave the flooded forest and grasslands. At low water, fish and dolphins are restricted to main rivers, deeper channels and lakes – and the fish are more concentrated. This is the time most dolphin mating takes place.
Did you know adult males carry sticks, branches and clumps of grass, and repeatedly toss them at the surface? Apparently this helps impress the girls...
How long will the calf stay with its mother?
The mother’s care lasts a long time and reproductively active females spend most of their lives accompanied by a dependant offspring (they can be pregnant and nursing at the same time). Lactation lasts from one and half to more than five and a half years
Do they interact with other species of whale or dolphin?
There is only one other dolphin species – the tucuxi or sotalia – whose habitat overlaps. Sotalia dolphins live in freshwater rivers and lakes but do not enter the flooded forest. Amazon River dolphins and sotalia hunt fish in the same river confluence hotspots, and they coexist in rivers and lakes. Occasionally they swim together and are seen interacting.
What sounds do Amazon River dolphins make?
Botos produce a wide variety of sounds: echolocation clicks, whistles and pulsed calls that include screams, barks, squeals, squarks, creaks, cracks and whimpers!
How long do Amazon River dolphins live?
The lifespan of an Amazon River dolphin is unknown but the oldest recorded female was estimated to be 32 years old. Females over 25 years of age continue to reproduce.
Do they have natural predators?
We humans are their biggest threat, whether it’s deliberate hunting for bait in the piracatingafishery, entanglement in fishing nets, dam construction, gold mining or climate change.
Are Amazon River dolphins endangered?
They are officially listed by the IUCN as Endangered. Populations are fragmented and continue to decline, as more botos are dying than being born.
Does the Amazon River dolphin have other names?
The Amazon River dolphin is also known as the Boto; bufeo; Araguaian dolphin; Bolivian river dolphin; pink river dolphin.
What is its scientific name?
Inia geoffrensis
What is the classification?
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Iniidae
Genus: Inia
When were Amazon River dolphins first discovered?
They were first described to science in 1817.
Top image: Getty images
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