Animals at a zoo in London were surprised with holiday treats hidden in stockings, scented balls and advent calendars ahead of Christmas Day. (Photos: VCG)

An Asiatic lion was captured sniffing at a scented ball for its treat.

A Bactrian camel was treated with a full stocking of grass.

Kumbuka, a silverback gorilla dug out a treat from the wooden slot marked with number 20 on December 20.