A sloth grows its own camouflage
The SLOTH moves so slowly that algae grow in its fur, turning it faintly green and helping it disappear among the leaves; moths and beetles live in the fur too. It eats leaves that give very little energy, and a single meal can take weeks to digest. About once a week it climbs down to the ground to go to the toilet — the most dangerous part of its life, because that is when predators can reach it.
The TAPIR, with a short trunk for grabbing leaves, looks like a pig but is related to horses and rhinos. The CAPYBARA of South America is the largest rodent in the world, a relaxed, semi-aquatic animal the size of a big dog. The ANTEATER has no teeth at all and a sticky tongue about sixty centimetres long, flicking in and out many times a minute.
Poison from the menu
Poison dart FROG species of Central and South America are brightly coloured as a warning, and some carry enough poison to be deadly. They do not make it themselves. They build it up from the ants, mites and other tiny insects they eat, so poison dart frogs raised in zoos on crickets and fruit flies are harmless.
The PIRANHA has a fearsome reputation, much of it from a 1913 visit to Brazil by the former American president Theodore Roosevelt, when locals staged a demonstration by starving fish and then dropping a cow into the water. Most piranhas are scavengers that also eat seeds and fruit, and people swim in piranha rivers all the time.
Eyes as big as a brain
The TARSIER of Southeast Asia is a small primate whose eyes are each about as big as its brain. It cannot move them in their sockets, so it turns its head almost all the way round instead, like an owl. The ORANGUTAN, whose name comes from Malay words meaning person of the forest, builds a fresh nest of branches high in the trees every night.
The TOUCAN's huge colourful beak is light and full of air pockets, and in 2009 scientists found that it works as a radiator: the bird sends more blood to the beak to lose heat on hot days. The CASSOWARY of Australia and New Guinea is a large flightless bird with a bony crest and a dagger-like claw on each foot, and it is best left alone.
Unknown to science until 1901
The OKAPI, a forest animal of central Africa with a dark body and striped legs, was not described by European scientists until 1901, although local people had always known it. It looks like a cross between a zebra and a horse but is the only living relative of the giraffe, and cleans its own ears with its long tongue.
The rest of the grid covers the canopy and the floor: the JAGUAR, the GORILLA and CHIMP, the LEMUR of Madagascar, the brightly coloured MANDRILL, the MONKEY, the MACAW and PARROT, the COATI, the ARMADILLO and the KINKAJOU, a cousin of the raccoon that hangs by its tail. Our rainforests page covers the forests themselves, and our Jungle Book page the story.