River Dolphins

Other Amazon Wildlife

What other unusual and wonderful animals share the River dolphins Amazon home?

The Amazon is home to two types of river dolphin – the Amazon river dolphin (or boto) and the Tucuxi (or sotalia). There are also some other large and endangered animals that live there………..

Amazon Manatee (Trichechus inunguis)
Manatees are gentle slow moving, fully aquatic mammals. They are also known as sea cows or water ox. Manatees are large and rotund in shape. Their skin is dark grey or black, and usually they have white mark on their tummies – this mark is unique to the individual manatee. They are big animals (and can grow up to 2.8m long and weigh up to half a ton!) but are difficult to see in the wild as only their nostrils appear above the murky water surface. They are vegetarians and eat aquatic water plants. Their closest living relatives are the elephant.

Manatees are graceful swimmers; they use their tails to power themselves along. Their flippers are very flexible and they use them to help move around over the river bed, and also for scratching, touching and embracing other manatees, and also for putting plants into their mouths.

Manatees can swim great distances and are found in rivers, channels, lakes and backwaters. At times they swim alone and other times they swim in groups. During the mating season several males can be seen pursuing a female. Pregnancy lasts for a full year and mothers give birth to a single calf underwater, perhaps once every 3 years. The calf will be dependant on suckling milk from its mother for 2 years. During this time the calf swims with its mother and learns to find the places where there are plants and fruits to eat (such as water hyacinth and water lettuce, floating grass).

Like river dolphins, humans are the only threat to manatees. Manatees are slow-moving and vulnerable to hunting. People kill them for their meat, skin, oil, fat and bones. Hunting pressure has diminished numbers of Amazonian manatees to such a degree that they are now endangered. Commercial hunting no longer occurs but they are still hunted by local people in many regions. In addition, manatees are threatened by degradation of food supplies (plants) by soil erosion resulting from deforestation.

Giant otter (Pteronura brasiliensis)
The giant otter is another record breaker for the Amazon – it is the world’s largest otter - and grows up to 1.8m long. They have a dark, dense, waterproof coat, which appears velvety when dry. The muzzle and chest is blotched with a pale colouring to varying degrees and each otter has its own unique marking. They have large, powerful tails and large, webbed feet to assist in swimming. They are agile swimmers and spend most of their time in the water.

They eat fish, shellfish and crabs and often carry a favourite rock around to help them break open shells. Giant otters are social, intelligent animals and typically live in groups of five to nine animals. In Spanish they are known as ‘river wolves’. Each group is comprised of an adult pair and their offspring, which may be from different breeding years. They are highly communicative and constantly interact through high-pitched hums, whining squeals and screeches.

Sadly, giant otters are now the rarest mammal in the Amazon – and a highly endangered species. No longer hunted for its fur, the giant otters survival now depends on protection of the areas in which it lives from destruction and pollution.

Giant otters prefer slow-moving rivers and streams and often set up their nests in calm, oxbow lakes where it is safer for the offspring, and where they have access to fish. They are also known to inhabit swamps and marshes. Home ranges can cover areas of up to 12 by 12km.

Anaconda
These are giant aquatic snakes living in the Amazon and are good swimmers. Anacondas are the world’s largest snake and can grow to 10m long and 250kg in weight (females are almost 5 times heavier than males). They weigh more than a cow and are the heaviest snakes in the world. The anacondas eyes and nostrils are set high on its head, allowing it to see and breathe with the rest of its body under water. After ambushing prey at a watering or feeding site, the anaconda coils itself tightly around its victim and squeezes it to death and then swallows it head first.

Caiman
The black caiman is one of the largest reptiles – a crocodilian – which can grow to up to 5m long. It is the largest predator in the Amazon. They eat fish and also terrestrial animals such as capybara and deer when they come close enough to the waters edge. They use their mouths and teeth to grab their prey and then hold it until it drowns and swallow it whole. Humans are their only threat – they are hunted for meat and leather. Females only lay eggs every 2 or 3 years and them looks after her young for several months.

Giant Amazon Turtles
Giant Amazon river turtles can grow to three feet in length and weigh as much as 110 pounds. During the low water season when beaches are exposed, female turtles return to the sandy beaches where they were born to lay their eggs. Come nightfall, each female digs a hole up to three feet deep. When its ready, she lays up to 180 eggs arranging them carefully with her tail and covers them. They hatch about 60 days later. The main serious threat to these and all Amazonian turtles is humans catching them to eat their meat and looting their nests to eat or sell eggs. There are two other turtle species that also make their nests on Amazon beaches.

Amazon Fish - Pirarucu (Arapaima gigas)
Not surprisingly the Amazon is also home to the world’s biggest freshwater fish, ‘the Pirarucu’. This is a giant! It can grow up to 8 feet long and weigh as much as two men. The Pirarucu is an air breathing fish; mature adults have a lung-like organ. An adult pirarucu will breathe once every 10 to fifteen minutes. If necessary, however, they can stay underwater for twice that time. The pirarucu thrives in stagnant, low oxygenated lagoons where other smaller fish -- lacking the pirarucu adaptations for air breathing -- become listless, easy prey. These giant fish are targeted by local people as they taste good (some people call them river cod for this reason). As a result, unfortunately the larger individuals are much rarer nowadays and there are laws in the Amazon preventing people from hunting the fish during the breeding season in an attempt to halt the decline and give the pirarucu chance to recover.

Piranha (Serrasalmus sp.)
Piranhas have a fearsome reputation but of the some 20 species of the fish in the Amazon, most are vegetarian, which explains why piranha are able to co-exist with other fish species. The most carnivorous piranha species -- the red-bellied piranha -- has razor sharp teeth which can shred flesh from bone in a matter of seconds.

All images © Fernando Trujillo/Omacha Foundation