Freshwater is a vital and scarce resource on our planet with only 3% of the water on Earth being freshwater rivers and lakes, the rest being oceans. Freshwater rivers and lakes are formed when hollows are made in the Earth, such as when land collapses after a magma flow allowing for rainwater or melted snow to flow through and accumulate in the empty space. However, even though freshwater biomes are not expansive, they are still home to over 100,000 different species of plants and animals. Many amphibian species, such as turtles, frogs, and alligators, live in freshwater biomes. Mammals, such as otters and beavers, live in freshwater biomes too, with many more mammals stopping by a river or lake for a drink.