A tree kangaroo, similar to kangaroos and wallabies found in the forests of New Guinea and Australia's Cape York, pulls a watermelon from a Santa sack in a festive version of Taronga Zoo's regular enrichment programme in Sydney. Behavioural enrichment is an important part of caring for the animals at Taronga Zoo, with zoo keepers and the Behavioural Studies Unit constantly setting new challenges for the animals. This includes hiding food so that the animals have to forage and work for their meals, stimulating their hunting abilities and in turn educating visitors about the extraordinary abilities of animals. Photo courtesy: AFP