Where Are the Animals?


Walk softly. Move slowly. It's more likely you will see some of the reticent animals of the rainforest.

This is still a (mostly) pristine forest. That doesn't mean that humans haven't shaped and used it. Some experts believe that early Mesoamericans contributed greatly to rainforest biodiversity by encouraging the sorts of trees that provided nuts and other foods. But prior to the 20th Century, the impact of migratory humans has been relatively light and the changes have not prevented sustainability.

So why are the animals so rare and shy today? (Forget that monkey that wakes you up each morning or the capybara that begs your lunch!) Most of them are hard to spot.

First, the forest is still full of predators, not the least of which are humans. Peruvians with a diet reliant on fish consider sloth and monkey prize species. And second, remember that almost all of the "civilization" in the rainforest lies along the navigable rivers--the highways. Move back from the highway and there are many places that animals can make safer homes.

Still, you can expect to see many of the common animals of the rainforest if you are alert, including:





Ah, for the Life of a Sloth

The two toed sloth C. didactylus is one of the rainforest's most reclusive animals. You'll have to look closely to see one on your river voyages. It eats leaves, roots and fruits (including cecropia), but its metabolic rate is only a third of that of other mammals. It can take a month for a sloth to digest a single good meal! It's 4 - 8 kg (6.8 - 17.6 pounds) and has fur that can be 15 cm (six inches) long.

The sloth barely moves in its leafy home, but when it does, it can speed at a meter a minute. That's just great for its hangers-on--an entire community of insects like beetles, algae, plants and fungi that live in its fur. (You could do an entire food chain by diagramming the algae, fungi and other commensals there!)

Once every few days, the sloth will move down to the ground to defecate, usually in a heavy rain to avoid predators like jaguars, ocelots, harpy eagles, anaconda and humans. Then it crawls slowly back up to its perch, to form a great platform for its community.

Keep your field glasses handy for this rainforest animal. And share the award-winning book Rainforest, Rainforest with your students.

Image source: Fermilab