The pink river dolphin, or boto, was long thought to be safe — protected by local folklore that warned against harming it. That is no longer true. In 2018 the IUCN moved the species from Data Deficient to Endangered as the evidence of decline became impossible to ignore. So what is driving the loss, and what can actually be done about it? For the full picture, start with our pink river dolphin species guide.
Why is the pink river dolphin endangered?
The boto's decline is overwhelmingly human-driven, and it stacks up from several directions at once:
- Gillnet drowning. Dolphins become tangled in nylon gillnets set for fish and drown — the single most pervasive threat across their range.
- Bait-hunting. Some botos are deliberately harpooned to be cut up as bait for piracatinga, a scavenging catfish. Researchers have documented harpoon and machete scars on captured animals.
- Mercury pollution. Illegal gold mining releases mercury into rivers, where it accumulates up the food chain into these long-lived top predators.
- Dams. River dams fragment populations and block the movements the dolphins depend on through the year.
- Extreme heat and drought. In 2023, during a record Amazon drought, more than 150 dolphins died in a single overheating lake where water approached the temperature of a hot bath — most of them botos.
How fast are they declining?
Because the dolphins are spread thinly across vast, hard-to-survey river networks, there is no trustworthy global count — numbers are thought to run into the tens of thousands, but the trend is the worrying part. A 22-year monitoring study in Brazil's well-protected Mamiraua Reserve found boto numbers halving roughly every decade. Declines that steep are among the most severe recorded in dolphins.
What's being done — and what works
Saving the boto is mostly about protecting rivers and working with the people who share them. The most effective measures are practical and local:
- Removing or modifying the gillnets that drown dolphins.
- Supporting fishers to step away from the bait-hunting trade.
- Monitoring mercury levels in water and wildlife.
- Responding quickly to stranded or entangled animals.
- Safeguarding key stretches of flooded forest the dolphins rely on.
Because botos cross national borders, lasting progress depends on locally led teams who know the waterways and have the trust of riverside communities — not outside groups parachuting in. That is the model WARN backs in Brazil and Colombia, channelling supporter gifts to in-country partners working on river-dolphin safety. If this matters to you, you can support that frontline work; even a small gift helps keep these rivers safer for the pink dolphins that depend on them.
Read the full Amazon river dolphin wildlife guide for the facts, IUCN status and conservation context — or donate to WARN to help fund the local partners protecting this species.
