Amazon River Dolphin
Inia geoffrensis
The pink dolphin that swims through the treetops of a flooded rainforest.
This dolphin doesn't live in the sea at all. It lives in fresh water, in the rivers and lakes of the Amazon and Orinoco in South America, where it is known as the boto. Grown-ups turn pink, it has a long beak with bristles on it, and its neck bends in ways no sea dolphin's can. When the rivers flood, it swims right into the forest.
On the conservation status
Endangered on the IUCN Red List since 2018. In one protected reserve in Brazil, scientists counted botos every month for 22 years and found that their numbers fell by about 70%. Nobody knows how many there are in total, but the main causes of the decline, fishing nets and killing botos for bait, happen all along the rivers where they live.
- Length
- Up to 2.5 m (8 ft); males are bigger
- Weight
- Up to 207 kg (456 lb) for a male
- Diet
- More than 43 kinds of fish
- Home
- Rivers and lakes of the Amazon and Orinoco
- Pregnancy
- About 11 months
- Colour
- Grey as a calf, pink as a grown-up
The good stuff.
A dolphin that never sees the sea
Botos live in fresh water their whole lives, in the Amazon and Orinoco rivers and the lakes beside them. That takes in six countries: Brazil, Bolivia, Colombia, Ecuador, Peru and Venezuela.
Why they turn pink
Calves are dark grey, and grown-ups turn pink, males most of all. Males also carry far more scars from the teeth of other males, and the pink is thought to come from all that rough fighting. Scientists are still working out exactly how it happens.
A neck that really bends
None of a boto's neck bones are fused together, so it can turn its head in every direction. That helps it wriggle between roots and branches where a stiff-necked sea dolphin would get stuck.
Swimming through the forest
Every year the rivers rise and flood the forest around them. Botos swim in among the tree trunks and roots to hunt for fish. Mothers with calves spend the most time there, where the water is calm and there are plenty of small fish.
Two kinds of teeth
Most dolphins have rows of teeth that all look the same. A boto has pointed ones at the front and broader ones at the back. It eats more than 43 kinds of fish, and it finds them in muddy water by clicking and listening for the echoes.
Killed for bait
Since about the year 2000, some fishermen have killed botos and used the meat as bait to catch a catfish called the piracatinga. Brazil banned fishing for piracatinga in 2015, but the ban is hard to enforce and the fishing goes on.
Wait, really?
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Males are about 16% longer than females and weigh about 55% more, which makes botos one of the whale and dolphin kinds where males and females differ most in size.
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Scientists still argue about whether there is one kind of boto or three: the Amazon, Bolivian and Araguaian river dolphins. For now the main scientific list counts them as one.
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In Amazon folklore, botos are magical creatures that can turn into people.
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Botos are known by other names too: bufeo, tonina, and in Spanish, delfín rosado, the pink dolphin.
What it sounds like
Clicks to find fish in water too muddy to see through, plus barks, squeaks, whimpers and cracks. Scientists have described about ten different calls.
We haven't found a recording we're allowed to share yet, so for now this one is a description.
Where you might see one
In the wild, on a river trip: the Amazon in Brazil, Peru, Colombia or Ecuador, or the Orinoco in Venezuela and Colombia. It's a long way from anywhere, so botos are a very special sighting.
The trouble
- Being killed for bait in the piracatinga catfish fishery
- Drowning in fishing nets
- Dams that cut up the rivers where they live
- Pollution, including mercury from gold mining
- Heat waves and droughts that warm the water
One real thing
Never buy anything sold as a boto charm or a boto eye. Most are fake, and selling them is against the law in Brazil. And if your family buys catfish from South America, ask what kind it is: the catfish caught with dolphin bait is sometimes sold under other names.
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