The book says: ants all live together in nests, and there are hundreds of thousands in each nest. They are animals that move on the ground, mainly crawling on the ground. We can often see ants moving in search of food. They walk back and forth along a certain route and never get lost. How do ants find their way?

It turns out that ants' bellies can secrete a substance called tracer. Usually when you go out of the hole, you move in an orderly way. The ants in front secrete tracers and leave traces on the road when they walk. Ants walking behind can follow closely when they smell this smell. Even if some ants are left behind temporarily, they can go along the original road without getting lost. The smell of the tracer formed a signpost for their progress. When you come back, follow this sign and go back to the cave.

If a worker ant finds the food source, it will release the tracer while walking on the way back; If it can't find food, it won't leave any traces where it crawls. So the richer the food, the more ants it attracts, and the more traces it leaves on the road. Tracer is a volatile substance, which will soon disappear as long as it is not strengthened. And the tracking is group-specific. So it will not be confused with other nests and other kinds of ants.

If you touch them repeatedly with your fingers and cut off their route signs on the way, the ants will form a ball and circle around them. Thus, they didn't get lost because they recognized the tracker. After the ants arrive at their destination from the nest, they will leave some smells along the way and then return to the nest. Touch each other with tentacles and notify other ants. Scientists have done an experiment on this problem. Scientists first identify an ant and vigorously clean up the place where he reaches his destination along the way. When the ant came back, it suddenly stopped at the place where the smell was wiped off. Looking for something while walking in circles. People come to the conclusion that ants can tell their directions by their sense of smell.

In order to confirm this conclusion, I did an experiment. I first prepared a twig about 10 cm, and put the bait-small candy on one end of the twig. I put this device near an ant nest. After a while, an ant came out to explore the road. After I led him to the stick, he went to the place where the sugar was put, as if he were smelling it. I took this opportunity to cut off the broken part of the stick by one centimeter. When the ant came back, it turned left and right where it was cut off, but it couldn't find its way home.

After a while, I repeated the above experiment, and the ants still didn't find their way home.

Through these two experiments, I finally know the secret of ants not getting lost. It turns out that ants can tell the direction by smell.