Ant Traffic

How do ants avoid gridlock when their trails narrow into one-way paths? Vincent Fourcassié, a biologist at Paul Sabatier University in Toulouse, France, set up experiments in which ants had to cross a narrow bridge to get from nest to foraging site and back. It turned out that different species follow different rules to determine who goes first. The typical black garden ant did not enter the bride if another ant was crossing from the opposite direction. In contrast, the leaf-cutter ant gave way for ants carrying leaves back to the colony. And the list goes on...