Two-by-two? London Zoo counts its animals in annual stocktake 'ZSL London Zoo' on Wednesday began its week-long annual stocktake, with keepers counting everything from lions to spiders. Keepers posed for the media with clipboards, and even an abacus in the lemur enclosure, but the count has a serious purpose: to keep track of new births and the success of the zoo's breeding programmes. The information is also shared with other institutions to help pair rare animals.