Bedfordshire's Whipsnade Zoo now has more than 3,500 animals.
Zookeepers have just finished their annual 'stocktake' where they counted every creature big and small.
They looked at everything from seven curious squirrel monkeys to 281 deer of eight different species.
It took a week to complete and the information will be shared with other zoos around the world.
The Zoo’s Southern white rhinos have been counted, as well as invertebrates, including ghost mantises and emperor scorpions, and over 60 species of birds, such as white-faced whistling ducks.
The annual audit takes keepers almost a week to complete and the information is shared with other zoos around the world via a database called Species360.
It's used to help manage the worldwide conservation breeding programmes for endangered animals.