Some rove beetles skim effortlessly on the surface of water.

They are pulled by the surface tension of the water in front of them.

They lower the surface tension at the rear of their bodies using a glandular secretion at the ends

of their abdomens.

This allows them to use the higher surface tension in their front as a driving force.

The same principle was used in the camphor-powered boats that were once children’s popular toys.

We have heard of Free Loaders. This beetle is a Free Rider.