If any animals at London Zoo have been sneakily stealing extra portions of food from their friends they’re about to be found out, because the annual weigh-in is taking place.

This means that every one of the 16,000 or so animals, across 750 species, including penguins, meerkats, lions and owls, are put on the scales and measured.

The measurements are then recorded into the Zoological Information Management System (ZIMS) where they can be shared with zoos across the world, which zoologists use to compare information on thousands of endangered species.

london zoo

The zoo's penguin's step up to be weighed

ZSL’s Zoological Director, David Field, said: “We need to know the vital statistics of every animal at the Zoo – however big or small.

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“This information helps us to monitor their health, their diets and their general well-being. By sharing it with other zoos and conservationists, we can use this knowledge to protect wild animals, and use it to assess their health, their behaviours and even their ages”.

Click through the slideshow below to see how some of the animals got on.

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  • London Zoo's annual weigh-in

    A giraffe waits to be measured as part of London Zoo's annual audit to monitor every animal at the zoo.

  • London Zoo's annual weigh-in

    Zoo keeper Vicky Fyson weighs a penguin as part of London Zoo's annual audit to monitor every animal at the zoo.

  • London Zoo's annual weigh-in

    A penguin is weighed as part of London Zoo's annual audit to monitor every animal at the zoo.

  • London Zoo's annual weigh-in

    A Galapagos giant tortoise is measured as part of London Zoo's annual audit to monitor every animal at the zoo.

  • London Zoo's annual weigh-in

    A spectacled owl is weighed as part of London Zoo's annual audit to monitor every animal at the zoo.

  • London Zoo's annual weigh-in

    Meerkats are weighed as part of London Zoo's annual audit to monitor every animal at the zoo.

  • London Zoo Annual Weigh-In - London

    dirk the girent tortus is weighed and measured during the zoo's annual weigh-in at London zoo in England

  • London Zoo Annual Weigh-In - London

    Zookeeper Don McFarlane, at ZSL London Zoo, weighs and measures an African Millipede during the zoo's annual weigh-in at London zoo in England