Carpenter ants follow trails. Just watch them wandering about on your wooden porch until they strike a trail of pheromones (chemicals ants use for communication) that another ant has laid down.

Ants don’t have noses, so they wave their antennas around to pick up the trail , then off they go on the road to ruin. (Carpenter ants destroy houses.)

Scientists know plenty about ants, including their ability to follow scent trails, but researchers at Harvard wanted to get a more detailed understanding of how exactly ants sniff, or taste, the pheromone-marked path.

First, some basics: Ants use their antennas to pick up chemical cues left by other ants.

And the chemical sense of ants, call it smell or taste or chemo-reception, enables them to follow straight trails, curved trails, even zigzags.