Bullfrogs, pythons and penguins were among creatures being coaxed onto the scales at London Zoo this week for the annual check on their weight and size.
The check-up allows keepers to assess the animals' general health, find out about pregnancies, when they are about to moult, and help to administer medicines according to their weight, the Zoological Society of London (ZSL) said.
The information is shared with zoos around the world by ZSL, a charity devoted to the worldwide conservation of animals and their habitats.
But actually getting animals to stand up and be measured isno easy task, involving for example tricking penguins into walking over scalesas they line up for their morning feed or hanging breakfast from up high toencourage lions to reach up to their full height.
"We have to know the vital statistics of every animal at thezoo, from the tallest giraffe to the tiniest ant," said ZSL's assistant curatorof mammals, Teague Stubbington.
"It helps to ensure that every animal we look after ishealthy, eating well, and growing at the rate they should – weight is aparticularly important indicator of health and wellbeing."
Not all the 19,000-plus animals across more than 560 species at London Zoo will be weighed: sometimes just one in a colony or group will be measured.
The annual weigh-in of animals, also including Asiatic lions, South African porcupines and South American coatis, will take a week to complete.