THEY may be vermin, but researchers at a North-East university have discovered that rats may be a lot brighter than their reputation as scavengers suggests.

A team from Durham University says it has made a major medical breakthrough after discovering that rats have a better memory than anyone had previously thought.

The psychologists have discovered that rats have the same sort of memory as humans - and the discovery may help research into conditions such as Alzheimer's disease.

The study, published in this month's Learning And Memory, show that rats can find hidden objects by remembering a one-off event, and can use this experience to seek out food or other objects.

Researchers Dr Madeline Eacott, Dr Alex Easton and research student Ann Zinkivskay say that, because the objects were hidden, the rats could only base their search on their recollection of their previous experience in that environment, and not on forms of memory such as a sense of familiarity.

Dr Easton said: "This recollection of where an object is in a given environment is like human episodic memory, or rather, the memory of past events.

"For example, when we remember what we had for breakfast we don't just think of the bowl of cereal on its own but, instead, we remember other details like the room in which we ate it and who else was there.

"The ability to mentally recreate a situation is crucial to human experience, not only allowing us to reminisce about past times, but it may also be the basis of the ability to mentally create possible futures."

Previously, it was believed that this ability might be unique to humans.

Dr Easton said: "This research represents a major breakthrough because, being able to study this type of memory in an animal like the rat will allow us in the future to study why this memory breaks down in these patients, and perhaps will allow us to develop ways to intervene."