These heartwarming pictures show a pack wolves -- bobbing for apples. The pups, who are homed at RZSS Highland Wildlife Park in the Cairngorms, thoroughly enjoyed taking part in the Halloween ritual. Douglas Richardson, Head of Living Collections at RZSS Highland Wildlife Park, said: "Although bobbing or dooking for apples is not exactly a standard wolf behaviour, because of the pups natural curiosity, they were straight into the water chasing the apples. "Coupling novel enrichment techniques with talks by the wolves' keepers, we hope to highlight the intelligence of a species that once roamed the hills around the Wildlife Park this Wolf Awareness Week."