The photo above is from the Manantee Amazon Cruise in Ecuador’s Amazon Rainforest.
Often curious enough to approach swimming or canoeing tourists, rainforest dolphins are one of the most popular river sightings of the Amazon Rainforest and one of the iconic Amazon Rainforest attractions.
Pink River Dolphins
The pink river dolphin (Inia geoffrensis) is found both in the Amazon and Orinoco basins. These rainforest dolphins have a flexible neck for probing their long, slim beak into the mud for prey. They dive for a short amount of time (about one to two minutes) before surfacing.
Pink dolphins are steeped in mystery and not a lot is known about their behaviour. They are suspected to hunt mainly using echolocation due to the murky water. Their teeth are suited to crushing crabs, armoured catfish, and freshwater turtles. They have peg-like teeth at the front for grabbing prey and flatter, crushing teeth at the rear.
Usually living a solitary life or sharing their world with a single partner, pink river dolphins are sometimes seen in groups of over twenty individuals. These rainforest dolphins give birth to a single calf between May and July.
The Grey Dolphin
The grey dolphin (Sotalia fluviatilis) occurs in two forms: a marine form around north east South America and a river form in the lower reaches of the Amazon Basin. Like the pink river dolphin, the grey dolpin is usually alone or in twos, but can be found in groups of ten.
Evolution of Dolphins
One of the most complete fossil sets we have documents the evolution of dolphins and whales from their land-living ancestors. We now have so many different fossils showing the transitional stages that we can conclude dolphins and whales evolved from a land living hoofed mammal. The most closely related living mammal to the dolphins’ ancestor is the hippopotamus. The land dwelling animal changed over millions of years to become more and more adapted to life in water.
People of the Amazon River have a wide variety of beliefs and stories about rainforest dolphins. Many of the stories involve the dolphins transforming into people and seducing the villagers.
One story from the Brazilian Amazon describes the following event:
“In Cachoeiri there lived two orphan girls, visited during the night by strangers dressed in white. They suspected that the two boyfriends were dolphins, and two men armed themselves with harpoons…. There appeared only one of the two mysterious young men. They shot him with three harpoons and the boy managed to reach the river and throw himself into it diving. On another day there appeared floating, dead, a big dolphin, with three harpoons . . . stuck in the back.”
Because rainforest dolphins are the villagers natural competitors (dolphins will eat the same fish the villagers catch), it’s as if the villagers elevate this competition to also include competition for wives and husbands (Cravalho 1999). The dolphins usually appear to the villagers in the form of white men that seduce the women only to return to the river. These stories may also be influenced by the rise of global travel.
Observing Rainforest Dolphins
The Tahuayo Lodge in Iquitos, Peru, has access to a primate research facility at the end of an Amazon River tributary. Here, I remember drinking a hot cup of coffee while watching two pink dolphins playing in the water below and I thoroughly recommend a tour of the Tahuayo Reserve (established for the red uakari).