�y��vlog

Biologists have uncovered the genetic secrets of the world's smallest diving mammals - water shrews.

Because of its unique geography, the province of British Columbia has the highest concentration of endemic species, such as the Vancouver Island marmot and water shrew.

It is not known how the water shrew - with a trauma injury on its back possibly caused by a mouse trap - came to be in the curry.

By comparing them with short-tailed shrews, the team found that water shrews do have relatively greater oxygen stores but Dr Campbell described them as "pushing the boundary of size for divers".

They studied wood, harvest, yellow-necked and house mice; field, bank and water voles; brown rats; hazel dormice and one non-rodent - the water shrew.