Hungry rats learn to drive
Mr Toad may be the character best-known for his motoring enthusiasm in The Wind in the Willows, but in real life it is Ratty who has the driving skills.
Scientists have trained rats to drive custom-built miniature cars and said those reared in more privileged surroundings were first to pass their tests.
Researchers in Virginia created the rat-operated vehicle (ROV) to test the creatures’ abilities as well as the effect on them of learning a complex skill.
Eleven male rats and six females were taught to drive the electric ROV, which moved forward when the rat grasped wire ‘‘handle bars’’, thus completing a circuit. In the first phase, the rodents learnt to enter the vehicle and drive forward in a straight line to retrieve a reward of Froot Loops cereal.
The researchers established that rats could then be trained to steer by touching different bars to move straight ahead and left or right, to reach a proferred snack 140cm away. The car reached a top speed of 1.7kmh. Rodents have previously been shown to be capable of learning to press a lever to move a vehicle that they were riding on forwards on a fixed track. However, the researchers said that their findings were the first to show that they could also control a motor vehicle in complex ways.
They said that rats raised in an ‘‘enriched’’ environment – in cages with toys and exercise facilities - exhibited far better driving performance than those reared in standard lab cages. After training several times a week over months, these privileged rats were able to pass the researchers’ driving test criteria, of four ‘‘clean’’ drives in a session. These rats continued to climb into the car and drive with apparent gusto even after food was no longer offered.
Kelly Lambert, of the University of Richmond, one of the authors of the study published in Behavioural
Brain Research, said: ‘‘Most of [the rats] learnt to drive to the goal, but not consistently enough to pass the experimental driving test. When trained more often, however, even the rats housed in standard housing conditions learnt to drive. ‘‘This reminds us that our brains are dependent on interactive, engaging environments to facilitate optimal performance. Our neural networks crave informative experiences like our lungs crave air to function.’’
The team also analysed stress hormones in the rodents’ faeces and found that the stress levels of both groups of rats reduced as they learnt the new skill.