9 July 2010 Last updated at 12:57 ET

Earliest evidence of pet tortoise in Britain

By Pallab Ghosh Science correspondent, BBC News

The discovery provides evidence of a "change in attitude" towards animals

Researchers have found the earliest archaeological evidence of a tortoise being kept as a family pet in Britain, at a castle in Staffordshire.

The find, which is reported in the journal Post Medieval Archaeology, dates to the late 19th Century.

The researchers say that, at this time, attitudes to keeping family pets "began to change".

The 130-year-old leg bone was found among the remains of cats and dogs

"A fondness for pets was more regularly expressed in literature," the researchers wrote in their article.

There has been evidence of turtles and terrapins in domestic situations dating back to the 17th Century - but it was believed that these animals were used for food.

The discovery of a 130-year-old tortoise leg bone at Stafford Castle, amongst the remains of cats and dogs, suggests that this animal was a pet kept by the castle's caretakers.

According to Dr Richard Thomas of Leicester University, who led the research, the keeping of pets had until then been considered "morally suspect".

"If you go back to the medieval period you can see that attitudes to animals in general were very much constrained by religious doctrine," he said.

"Man was given dominion over all animals, and where close relationships with animals are found, suspicion is aroused.

"In witchcraft, for example, having a close animal companion is seen as very sinister and a sign of devilry."

The discovery of the tortoise bone is seen as evidence that this was an era of the start of a social and cultural change.

It was then that ordinary people began keeping animals - not for any practical use - but because they were fond of them and wanted them as family pets.