Tucuxi Sotalia fluviatilis

Tucuxi Sotalia fluviatilis

IUCN Red List Status: Endangered

Location: #Brazil, #Peru, #Colombia, #Ecuador

Found throughout the #Amazon and Solimões River systems, including major tributaries and large lakes. Their range spans lowland rainforest areas of Brazil, southeastern Colombia, eastern Ecuador, and southern Peru.

The #Tucuxi, a small freshwater #dolphin of #Peru, #Ecuador, #Colombia and #Brazil now faces a dire future. Once common throughout the Amazon River system, they are now listed as #Endangered due to accelerating population declines. Threats include drowning in fishing nets, deforestation, mercury poisoning from gold mining, #palmoil run-off, oil drilling, and dam construction. A shocking 97% decline was recorded over 23 years in a single Amazon reserve. Without urgent action, this elegant and playful river dolphin could vanish from South America’s waterways. Use your wallet as a weapon against extinction. Choose palm oil-free, and #BoycottGold #BoycottPalmOil #Boycott4Wildlife

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Playful and intelligent #Tucuxi are small #dolphins 🐬 of #Amazonian rivers in #Peru 🇵🇪 #Brazil 🇧🇷 #Ecuador 🇪🇨 and #Colombia 🇨🇴. #PalmOil and #GoldMining are major threats 😿 Fight for them! #BoycottGold #BoycottPalmOil #Boycott4Wildlife @palmoildetect palmoildetectives.com/2025/11/…

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Clever and joyful #Tucuxi are #dolphins 🐬💙 endangered by #hunting #gold #mining and contamination of the Amazon river 🇧🇷 for #PalmOil #agriculture ☠️ Use your wallet as a weapon and #BoycottGold 🥇🚫 #BoycottPalmOil 🌴🚫 #Boycott4Wildlife @palmoildetect palmoildetectives.com/2025/11/…

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Appearance & Behaviour

Tucuxis are often mistaken for their oceanic dolphin cousins due to their streamlined bodies, short beaks, and smooth, pale-to-dark grey skin. But these freshwater dolphins are wholly unique—adapted to life in winding river systems where water levels rise and fall dramatically with the seasons.

What sets them apart is their remarkable intelligence and tightly knit social groups. Tucuxis are playful and curious by nature. They leap from the water in graceful arcs, sometimes spinning mid-air.

The Tucuxi, sometimes called the ‘grey dolphin’ due to their uniform colouring, resembles a smaller oceanic dolphin, with a streamlined body and slender beak. Their colour varies from pale grey on the belly to darker grey or bluish-grey along the back.

They travel in small groups of two to six, displaying coordinated swimming patterns. In rare cases, they may form groups up to 26 individuals, particularly at river confluences. Known for their agility, they leap and spin in the water with a grace that belies their size. Tucuxis are particularly drawn to dynamic habitats like river junctions, where waters mix and fish gather.

Threats

• Widespread deforestation from palm oil plantations Palm oil plantations are rapidly expanding across the Amazon, clearing vast tracts of forest that stabilise riverbanks and filter water. This deforestation leads to increased sedimentation in rivers, altering flow patterns and reducing water clarity—conditions that directly disrupt the Tucuxi’s feeding and movement. Run-off from fertilisers and pesticides used in palm oil monocultures also poisons aquatic ecosystems, harming Tucuxis other Amazonian dolphin species and the fish they rely on.
• Toxic mercury pollution from gold mining Artisanal and illegal gold mining in the Amazon releases massive quantities of mercury into the water, contaminating fish and other aquatic organisms. Tucuxis, as top predators, ingest this mercury through their prey, which accumulates in their tissues and causes neurological damage, weakened immunity, and reproductive failure. Mercury exposure is one of the most insidious threats, as it persists in ecosystems long after mining has ceased.
• Incidental drowning in fishing nets Tucuxis are frequently caught and killed in gillnets and other fishing gear as bycatch. Tucuxis and other Amazonian dolphins often inhabit the same confluence zones and productive fishing grounds targeted by local communities, making entanglement almost inevitable. Many carcasses are never recovered, having either been discarded by fishers or lost to river currents, meaning actual mortality rates are likely far higher than reported.
• Deliberate hunting for use as fish bait Though illegal, Tucuxis continue to be targeted and killed in parts of Brazil, especially near the Mamirauá and Amana Reserves, where they are used as bait in the piracatinga (catfish) fishery. This brutal practice involves harpooning or netting dolphins and using their flesh to lure fish, often alongside the killing of Botos. Despite a national ban, weak enforcement and ongoing demand mean this threat persists in remote and lawless regions.
• Illegal fishing with explosives and toxins In certain areas, particularly in Brazil and Peru, fishers use home-made explosives and poisoned bait to stun or kill fish en masse. These destructive methods harm or kill Tucuxis who are attracted by the sudden appearance of dead or stunned prey. The concussive force of explosions and the ingestion of poisoned prey result in slow, agonising deaths for affected dolphins.
• Construction of hydroelectric dams Dams fragment Tucuxi populations by blocking their movement along river corridors, reducing access to feeding and breeding grounds. These projects alter seasonal water flow, raise water temperatures, and flood critical habitats—conditions that significantly disrupt dolphin ecology. Brazil alone has 74 operational dams in the Amazon basin, with over 400 more planned, posing a long-term existential threat to freshwater cetaceans.
• Run-off and contamination from palm oil, soy and meat agriculture In addition to habitat loss, palm oil and soy plantations along with cattle ranching generates enormous volumes of chemical-laden waste, which enters waterways and poisons aquatic life. This pollution affects Tucuxis both directly and indirectly—exposing them to harmful substances and killing off sensitive fish species. As plantations replace biodiverse forests, the ecosystem becomes less resilient, accelerating the decline of species like the Tucuxi.
• Bioaccumulation of heavy metals and industrial pollutants Tucuxis, like many river dolphins, suffer from exposure to persistent organic pollutants such as PCBs, DDT, and flame retardants, as well as heavy metals like lead and cadmium. These toxins accumulate in dolphin tissues over time, weakening their immune systems, interfering with reproduction, and making them more vulnerable to disease. Contaminants originate from industrial waste, agriculture, and mining, and are now widespread across the Amazon basin.
• Habitat fragmentation from infrastructure and oil development Roads, oil pipelines, and shipping corridors criss-cross many parts of the Tucuxi’s range, slicing through their habitat and increasing the risk of collisions with boats. These developments also bring noise pollution, which can interfere with echolocation and communication. Fragmentation leads to isolated subpopulations, reducing genetic diversity and making recovery more difficult.

Geographic Range

The Tucuxi inhabits the Amazon River basin, spanning: Brazil, Peru, Colombia, Ecuador These river dolphins occur as far west as southern Peru and eastern Ecuador, and as far north as southeastern Colombia. They are notably absent from Bolivia’s Beni/Mamoré system, the Orinoco basin, and upper reaches above major waterfalls or rapids.

Their range includes wide, deep rivers and lakes, avoiding turbulent rapids and shallow areas. Despite overlapping with the Amazon River Dolphin (Inia geoffrensis), Tucuxis do not enter flooded forest habitats and stay closer to main river channels.

Diet

Tucuxis feed on more than 28 species of small, schooling freshwater fish, including members of the characid, sciaenid, and siluriform families. During the dry season, fish are concentrated in shrinking waterways, making them easier to catch. In contrast, flooding season disperses prey into forested areas, beyond the Tucuxi’s reach. They prefer to feed at river junctions and along confluences, where nutrient-rich waters concentrate fish populations.

Mating and Reproduction

Little is known about their mating behaviours. However, individuals appear to remain within familiar ranges for many years, and females likely give birth to a single calf after a long gestation. Calves are dependent for an extended period, learning complex navigation and foraging skills in rapidly changing river systems. The estimated generation length is 15.6 years.

FAQs

How many Tucuxis are left in the wild?

There is no comprehensive global population estimate. However, surveys from 1994–2017 in Brazil’s Mamirauá Reserve show a 7.4% annual decline—amounting to a 97% drop over three generations (da Silva et al., 2020). If this trend reflects the wider Amazon basin, the species could be on the brink of collapse.

How long do Tucuxis live?

Exact lifespans are unknown, but based on reproductive data and life history modelling, their generation length is around 15.6 years (Taylor et al., 2007), suggesting natural lifespans of 30–40 years.

How are palm oil and gold mining affecting Tucuxis?

Out-of-control palm oil expansion results in massive deforestation and run-off, clogging rivers with sediment and toxic agrochemicals. Gold mining adds mercury into aquatic ecosystems, where it bioaccumulates in fish—Tucuxis’ main food source. These pollutants cause reproductive harm, neurological damage, and immune system failure in dolphins.

Do Tucuxis make good pets and should they be kept in zoos?

Absolutely not. Tucuxis are intelligent, wild animals. Keeping them in captivity is deeply cruel and has no conservation benefit. Wild capture destroys families and can devastate local populations. If you care about these dolphins, say no to the exotic pet trade and the cruel zoo trade.

What habitats do they prefer?

Research in Peru’s Pacaya-Samiria Reserve shows that Tucuxis prefer river confluences and wide channels, particularly during the dry season when fish density is higher (Belanger et al., 2022). Feeding activity is especially concentrated in areas where whitewater rivers meet blackwater tributaries, creating nutrient-rich hotspots.

Take Action!

The Tucuxi is vanishing before our eyes. To protect them:

• Boycott palm oil and gold products linked to Amazon destruction.

• Choose fish-free and vegan products to reduce pressure on river ecosystems.

• Support indigenous-led conservation across the Amazon.

• Campaign for a ban on destructive dams, and the end of illegal fishing.

#BoycottPalmOil #Boycott4Wildlife #Vegan #BoycottMeat

Support the Tucuxi by going vegan and boycotting palm oil in the supermarket, it’s the #Boycott4Wildlife

Support the conservation of this species

This animal has no protections in place. Read about other forgotten species here. Create art to support this forgotten animal or raise awareness about them by sharing this post and using the #Boycottpalmoil #Boycott4Wildlife hashtags on social media. Also you can boycott palm oil in the supermarket.

Further Information

Belanger, A., Wright, A., Gomez, C., Shutt, J.D., Chota, K., & Bodmer, R. (2022). River dolphins (Inia geoffrensis and Sotalia fluviatilis) in the Peruvian Amazon: habitat preferences and feeding behaviour. Latin American Journal of Aquatic Mammals, 17(1). doi.org/10.5597/lajam00268

da Silva, V., Martin, A., Fettuccia, D., Bivaqua, L. & Trujillo, F. 2020. Sotalia fluviatilis. The IUCN Red List of Threatened Species 2020: e.T190871A50386457. dx.doi.org/10.2305/IUCN.UK.202…. Accessed on 06 April 2025.

Monteiro-Neto, C., Itavo, R. V., & Moraes, L. E. S. (2003). Concentrations of heavy metals in Sotalia fluviatilis (Cetacea: Delphinidae) off the coast of Ceará, northeast Brazil. Environmental Pollution, 123(2), 319–324. doi.org/10.1016/S0269-7491(02)…

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