Here, 1,000 miles from the sea, are dolphins.
A newly identified species of river dolphin found nowhere else on Earth.
In these black, tangled waters,
they have become almost totally blind, so they move slowly,
carefully using their sonar to scan the forest floor for fish.
If this forest can hide a new species of dolphin...
what else might there be here, awaiting discovery?
At the shallow margins of the flooded jungle, rivers flow through lush vegetation.
Here, food is so abundant, it supports giants.
Capybara, the biggest rodents in the world...
giant otters the size of a man...
and the rulers of these rivers... caiman.
They grow to ten feet long and kill anything they get between their jaws.
But there are more artful hunters... drawn here from the surrounding forest.