Baikal on each side is surrounded by a mountain range and the shores of the lake consist of steep rocks, which means that the mud does not flow into the lake in large quantities.
In 2011, researchers discovered two new species of freshwater stingrays in the Amazon River.
The Heliotrygon (rosai and gomesi), commonly referred to as the Pancake stingrays, is the first new genus of stingrays from the Amazon described since 1987.
A single hectare of tropical forest can contain 42,000 different species of insects, up to 807 trees of 313 species, and 1,500 species of land plants (Embryophyta).
It is likely that tropical forests contain many millions of species of plants, insects, and microorganisms that have yet to be discovered.
