Tucuxi look somewhat similar to bottlenose dolphins, with broad flippers and pronounced beaks. Their bodies are muted blue-grey in colour, while their bellies are much lighter shades of ivory, grey or pink. Tucuxi have low, triangular dorsal fins. They are quite small compared to the other river dolphin species, only growing to about 1.5 metres long and weighing around 50kg at adult maturity.
Like other dolphin species, tucuxi rely heavily on echolocation to communicate, navigate and find food in the dark and sometimes turbid waters where they live13. However, unlike Amazon river dolphins that enter into flooded forests, tucuxis have less pronounced melons (foreheads where echolocation clicks are amplified), since they do not need to navigate through many obstacles.
Tucuxi. Illustration by Uko Gorter.
Reproduction and growth
Gestation is estimated at 11-12 months14. Calving peaks during the low water period of the Amazon in October and November, and they live to be about 15-16 years old 15.
Feeding habits of the tucuxi are believed to be generalist, including a variety of fish and crustaceans, as is the case with Amazon river dolphins. However, studies on tucuxi diet are scarce due to difficulties in sampling this animal.
(c) Jessica Melo IDSM
To human observers, tucuxi appear playful, vivacious and extremely sociable. The tucuxi is the only river dolphin that jumps out of the water, like its marine cousins. This species seems to be more social than Amazon river dolphins, congregating in groups of up to 30 individuals2. Tucuxi are fast swimmers, and display short dive times of only 30 seconds to one minute.