Staff at London Zoo started counting 18,000 animals as part of their annual stocktake.
The Zoo has 712 species and it takes around a week for each individual animal to be counted. However, tiny creatures such as ants and locusts are counted in colonies.
"It's an opportunity for all of the animal teams to go out and make a record of how many individual animals we've got on each section. It's part of our zoo licensing requirement to take an inventory of the animals," said Zoological Society London manager Mark Habben.
Produced by Claudia Romeo.