Shirley, a Labrador Retriever who can detect low blood sugar levels in his diabetic owner (L) and Jake, a Cocker Spaniel who worked as a 7/7 sniffer dog, look at the photographers during a preview for the Kennel Club's Friends for Life competition in London February 28, 2011. The competition, which will be held at the Crufts 2011 Dog Show, celebrates dogs who have triumphed in adversity and helped mankind through bravery, support or companionship. REUTERS/Suzanne Plunkett (BRITAIN - Tags: ANIMALS)