24 August 2023

Penguins, tigers and gorillas were just some of the animals that hopped, skipped and jumped on to our scales today as keepers began recording each animal’s vital statistics for our conservation zoo’s Annual Weigh In.  

With more than 14,000 animals in our care, our keepers spend hours throughout the year recording the heights and weights of all the animals – vital information which helps us to monitor their health and wellbeing.  
The Annual Weigh In is a chance for keepers at our conservation zoo to make sure the information we’ve recorded is up-to-date and accurate, with each measurement then added to the Zoological Information Management System (ZIMS), a database shared with zoos all over the world that helps zookeepers to compare important information on thousands of threatened species.  
Head of Zoological Operations, Angela Ryan said: “We record the vital statistics of every animal at the Zoo – from the tallest giraffe to the tiniest tadpole. 
“Having this data helps to ensure that every animal we care for is healthy, eating well, and growing at the rate they should - a key indicator of health and wellbeing.” 
“For example, a growing waistline can help us to detect and monitor pregnancies, which is vitally important as many of the species we care for are threatened in the wild and part of international conservation breeding programmes - London Zoo coordinates the global programme for Sumatran tigers, for example.” 

A meerkat is on the scales at the annual weigh in
London zoo weigh-in
gorilla being measured

“By sharing information with other zoos and conservationists around the world, we can all use this knowledge to better care for the species we’re striving to protect.” 
With different personalities to take into account, zookeepers use clever tactics to entice the animals to stand up and be measured; ‘tricking’ this year’s Humboldt penguin chicks into walking over scales one by one as they line up for their morning feed, and encouraging Bolivian black-capped squirrel monkeys onto the scales with tasty treats.  
Also making our Annual Weigh In debut this year was Western lowland gorilla Kiburi - who arrived as part of a global breeding programme for the Endangered species last November - and Critically Endangered Sumatran tiger cubs, Zac and Crispin, who recently celebrated their first birthday.  

penguins being weighed
stick insect being measured

This weight check gives our veterinarians and zookeepers important information about the cubs’ development, with the team estimating it won’t be long until the growing duo record the same vital statistics as mum and dad.  
We are home to more than 14,000 amazing animals, including Humboldt penguins, Sumatran tigers and Asiatic lions.  Protecting threatened species through conservation, we also contribute to the reintroduction of Extinct-in-the-Wild species, such as partula snails. Every ticket to our conservation zoo supports ZSL’s global science and conservation work.

Plan a visit this bank holiday weekend