Biologists at UC Berkeley and the University of Texas Medical Branch have discovered that when some tropical ant species fall out of a tree, they have the ability to glide and actively direct their descent to land at the base of the trunk they fell from. From the press release (with cool video):
(Researcher Stephen) Yanoviak's earlier observations (in Peru) combined with the videotaped tests in Panama established that the ants basically reorient their bodies so their hind legs and abdomen point toward the tree, and use their head-up fall through the air to take them feet-first toward the trunk. How they land is still a mystery, but evidently claws on their back legs act like grappling hooks to snag the trunk and hang on.
"When they drop, they often glide away from the trunk, then turn and come in backwards," (Berkeley biologist Robert) Dudley said. "Their 180-degree turns are pretty dramatic in the absence of wings."