Aquatic beetles spend most of their lives in the water. In North America, there are 500 known species, and some 5,000 species worldwide. They can breathe under the water using an air bubble they"ve trapped on the water surface. These beetles which have exquisitely complex systems, have retained the same perfect features for millions of years. The fossil aquatic beetle pictured is evidence that these beetles today are just the same as they were 108-92 million years ago and have never undergone evolution.