It is entirely aquatic and is the first species of frog known to science that has no lungs.

They are also the only entirely aquatic Mecoptera.

Engaeus species are not entirely aquatic, because they spend most of their lives living in burrows.

All species are closely associated with water and some are entirely aquatic.

A few are entirely aquatic, and swim rapidly.

It is entirely aquatic, breeding and laying its eggs in the same lake where it lives.

The Japanese giant salamander, being restricted to streams with clear, cool water, is entirely aquatic and nocturnal.

The diet is almost entirely aquatic plants.

The animal, scientists say, was flexing itself out of an entirely aquatic existence with a body almost ready for life on land about 365 million years ago.

Due to their entirely aquatic nature, their legs are short, with four-toed feet.