When A Rat Smells A Rat
Published:14 Jul.2023 Source:University of Tokyo
Some animals release chemical pheromones which can trigger behavioral or hormonal changes in other animals. It is known that calm rats can reduce the fear of nearby rats, but the exact mechanism was unknown. Researchers, including those from the University of Tokyo, have found the pheromone responsible and demonstrated its effect both on lab rats and rats in the human environment. Their findings could lead to a new kind of humane pest control.
It has been known for some time that, within the same species, rats which are in a relaxed state can imbue a similar state in nearby rats. Essentially, they can calm each other down without any direct interaction. This is due to pheromones, biological compounds in the air, released from the relaxed rat and received by the scared rat, altering their state. But the nature of the pheromones involved was unknown until now.
The main pheromone the team found released by relaxed rats was 2-methylbutyric acid (2-MB), which is incidentally found in the aromas of cheese and wine. They first determined this was what they were seeking by making sure it did indeed reduce the fear in other lab rats. Then they laced one of two identical small chambers with 2-MB to see if the rats would show any preference toward either, which they did. This directly showed that rats felt comfortable to sniff the pheromone. Given the striking effect it seemed to have, the team also wanted to see if it would work on wild rats in urban environments. Based on their results, the team believe that 2-MB could be used to create a form of humane pest control. It could be used to lure urban rats into nonlethal traps and also keep them calm while they're being transported out of the urban environment.