Young visitors look at penguins through a glass port hole at the London Zoo in London, Britain, on Jan. 4, 2016. The zoo's annual stocktake requires keepers to check on the numbers of every one of the 800 different animal species, including every invertebrate, bird, fish, mammal, reptile, and amphibian.
A zoo keeper poses with Humboldt penguins during the annual London Zoo stocktake. The compulsory annual count is required as part of the zoo's license.
A London Zoo staff member stands with a Llama.
Zookeeper Collene Gibbings poses for a photograph next to a tank of moon jellyfish.
A London Zoo staff member holds a chameleon.
Keeper Jamie Mitchell poses with a Mexican Red-Kneed Tarantula.
A ring-tailed lemur looks up during the annual stocktake. The annual audit takes keepers a week to complete and all of the information is shared with zoos around the world via the International Species Information System, where it's used to manage the worldwide breeding programs for endangered animals.
Zookeeper Veronica Heldt poses for a photograph as she counts meerkats.