Scientists have taught a group of rats to drive small cars as part of research on their stress levels.
The study, at the University of Richmond, in Virginia, USA, used a car made from a plastic jug on wheels.
The floor was made of aluminium and three copper bars at the front enabled the rats to steer by gripping any of the bars with their paws, completing a circuit. In return for their efforts, the rats were treated with bits of cereal, reports the AFP news.
After months of training the rats, researchers collected their faeces to test for the stress hormone corticosterone, as well as for dehydroepiandrosterone, an anti-stress hormone. All of the rats had higher levels of DHEA, which the scientists believe could be linked to the satisfaction of having learned a new skill.