Professor Stephen Hall discusses the breed's classification

It is the first time in more than a century that a new breed has been identified and it will be entered in the World Dictionary of Livestock Breeds.

The herd, which has been undisturbed for the past 25 years on the island of Swona, has been breeding by natural selection for several generations.

Because the herd has been undisturbed, it has regained traits common to its ancestors.

'Survival of fittest'

The cattle are wary of humans and can display some aggression. Scientists have shown interest in the herd because it reflects Charles Darwin's theory of survival of the fittest.

The herd might be a source of BSE free genetic material

Swona was abandoned by humans in 1974 when its ageing population began to die out and was not reinvigorated by new blood.

The cattle were left to their own devices and have since been studied by Professor Stephen Hall, a zoologist at De Montfort University in Leicester.

He told the BBC: "In the herd at the moment there are 20 cattle, and seven of those are mature bulls and that's not the sort of thing you would get in any commercial farm.

"The bulls will contest among themselves - they might fight, or they might assert their dominance in different ways and it is the fittest bull which will sire the calves."

Because the cows have been free of human interference - with the ability to make their own breeding choices - they are reckoned to have diverged enough genetically to be classed as a new distinct breed.

Human influence

All other breeds in Britain have evolved as a result of human influence in the breeding process.

Professor Hall said: "These are the only cattle which were developed during the agricultural revolution and which have since reverted to the wild."

The herd has developed by survival of the fittest

The herd is free of BSE and may prove to be a genetic source for research on the condition.

"We are having to rethink what we use livestock for, and in many parts of Scotland where hill farming is difficult to see in many ways as an economic future we might be starting to think about animals to maintain the landscape," he said.

"That is the sort of thing where a very hardy, independent breed of cattle like these could be useful.