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Water dwellers

Video: water in the Tropical Forest

Over time, aquatic animals like capybaras, caimans and piranhas have developed different skills and features to help them move about, feed and detect their surroundings.

Like to learn more about them?


Yacare caiman

Image: yacare caiman
yacare caiman

A caiman’s teeth, just like those of alligators and crocodiles, fall out and grow back throughout its lifetime. Since they normally have approximately 80 teeth, caimans go through about 2,000 to 3,000 teeth in the course of their lives.

Video: yacare caiman

Although their jaws are very strong, yacare caimans cannot move them from side to side or chew. They have to swallow their prey whole.


Image: arowana

Arowanas are prehistoric fish. Because their mouths angle upwards, they have to feed mainly at the surface.

They can leap more that one metre out of the water to catch the insects they eat in the wild. At the Biodôme we feed them mainly fish and shrimp.


Image: sunbittern

Sunbitterns have quite a varied diet: invertebrates, crabs, fish and frogs. When they hunt, they move very slowly, their heads held back, and then strike at their prey with lightning speed.

Video: sunbittern

They often rinse their food in water before eating it. At the Biodôme we feed them mice, smelt and insects.

Ibis and spoonbill

Image: scarlet ibis
scarlet ibis

Scarlet ibises and roseate spoonbills feed on aquatic insects, molluscs, crustaceans and minnows. Scarlet ibises have long down-curved bills. They nod their heads up and down as they search for food in the mud, as if they were saying “yes.”

Video: ibis and spoonbill

When feeding, roseate spoonbills sweep their flat bills across the surface from side to side, as if they were saying “no.”



The whiskers of redtailed catfish and tiger shovelnose catfish are very important sensory organs. They help the fish locate their prey.

Image: tiger shovelnose catfish
tiger shovelnose catfish
Image: redtailed catfish
redtailed catfish

Yellow anaconda

Image: yellow anaconda
yellow anaconda

Snakes continuously flick their tongues back and forth, allowing them to “smell.” Their tongues collect air molecules and carry them to what is called a Jacobson’s organ, which analyzes them.

Image: organe de Jacobson
organe de Jacobson

Video: yellow anaconda

Scientists think that by collecting this information from two different points, snakes can tell which way their prey is heading. They can also smell with their nostrils.

Piranhas and tetras

Red-bellied piranhas and cardinal tetras live in schools.

They are well adapted to their dimly lit environments. The sun’s rays penetrate down through the water and reflect off the specialized cells on their skin, so that they can recognize their companions by their colours.

Image: cardinal tetras
cardinal tetras
Image: red-bellied piranhas
red-bellied piranhas

Capybara and caiman

Image: capybara

The eyes and nostrils of animals that spend lots of time in the water, like capybaras, are often located on the top of their heads. They can see and breathe while keeping most of their bodies underwater.

Image: oeil de caïman
oeil de caïman

Yacare caimans’ eyes are covered with a transparent membrane that helps protect them while they are underwater.


Jacana and gallinule

Northern jacanas and purple gallinules are shore birds. Did you notice their long toes? This adaptation lets them walk on floating water plants.

Video: jacana and gallinule
Image: purple gallinule
purple gallinule


Capybaras are the world’s largest rodents. Their partially webbed feet are useful not only for swimming, but also for supporting their weight on muddy riverbanks in the wild.

Image: capybara foot
capybara foot
Image: capybaras in water
capybaras in water

Green basilisk

Video: green basilisk

Green basilisks can escape predators by running across the surface of the water.

Their long, partially webbed feet make for a large surface that helps keep them afloat. If they slow down, they will sink – but they are also excellent swimmers.

Image: green basilisk hind leg
green basilisk hind leg
Image: green basilisk
green basilisk

Yellow-spotted Amazon turtle

Image: yellow-spotted Amazon turtle
yellow-spotted Amazon turtle

The shell of yellow-spotted Amazon turtles is well adapted to their natural surroundings: its flattened shape lets them glide through the water more easily. Their webbed feet also help them move around faster, which is useful when they are hunting for food or fleeing predators.

Image: yellow-spotted Amazon turtle nostrils
yellow-spotted Amazon turtle nostrils

Did you see their large nostrils? That’s so they can breathe while remaining hidden in the water.

For more information:
Descriptive records

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