Israeli scientists have revealed how they have trained mice to be able to sniff out bombs.
The animals work inside a machine, air is blown over the person who might be carrying something illegal and into the chamber where the mice are.
They can detect even small amounts of explosives and have been taught to run to a special corner when they smell them.
This then sets off an alarm to alert people to the illegal substances.
If the machine is a success it could be used as part of security at airports in the future.