Keeper Darren Jordan comes face to face with a Von der Deckens Hornbill
Every morning school teachers take a register to count the number of kids in school and check that no-one's skiving.
And every year the keepers at London Zoo do a similar thing to work out how their animals are doing and keep track of any unexpected arrivals.
Newsround's Sally Meeson dusted off her clipboard and hit the zoo for some serious animal counting!
It's a really busy time at the zoo as there are over 600 species to get through... and since animals don't tend to keep still for long it's pretty easy to lose count!
Wandering through the main entrance it's clear that this is a big job. Penguins aren't just sitting quietly on rocks eating fish, they're swimming, playing and hiding. And have you ever tried to get a cheeky monkey to sit still and be counted? Forget it!
Head past the wild boar pen, the flamingo cage and the tiger enclosure and there's a special new area called the African bird safari. Some of the loudest, most colourful and rarest birds from Africa live here. They've all got really exotic names like Scarlet Ibis, Lilac Breasted Roller and Superb Starling.
Their keeper Darren Jordan works hard to work out how many birds he has but is constantly distracted by a bird called a Von der Deckens Hornbill which swoops down onto his clipboard every time he thinks he's got his final figure!
Dr Heather Koldewey is the senior curator of London Zoo's aquarium and she says that finding out how many baby animals they have is an exciting part of the animal count. She told us: "We've had another great year at London Zoo. We've had a giant anteater born, many different kinds of small monkeys and marmosets, not to mention the fish, the bugs, the reptiles and the birds."
But she admitted that some animals are easier to count than others: "If you're counting giraffes or gorillas it doesn't take very long but when you're faced with an enormous fish tank or if you're looking at a whole tree covered in stick insects then that obviously takes a little bit longer."
The creatures that take the longest to count are the creepy crawlies that live in a building called Bugs.
Keeper Donald McFarlane gets attacked by stick insects while trying to count them
Donald McFarlane, the bug-keeper, knows this more than most. Armed with a clipboard and pen which are crawling with stick insects he explained: "There are so many and they come in all sorts of shapes and sizes. And many are very well camouflaged so it's difficult to decide which is an animal and which is a plant - some are under a millimetre in size!"
But other creatures are so few and so well known by the zoo staff that counting them's a doddle. For example just past the lions, emus and kangaroos you'll find a little bunch of creatures which the zoo keepers lovingly call "The Wombles".
Their real name is Coati and they're a type of racoon from South and Central America. But because their snouts are long people think they look like Wombles which were creatures from an 80s children's TV show.
Keeper Mark Habben with "The Wombles" or coati as they're really called
But even though they're few in numbers they put up a fight when it came to being counted as they're active creatures which wriggle a lot and love burrowing for worms. They prove that even keeping track of a small set of animals can be a tough job!
So next time you're at the zoo, strolling casually from cage to cage, spare a thought for the poor old souls who once had to count every single one of the creatures inside them!!