From tallest giraffe to tiniest tadpole: London Zoo conducts annual weigh-in

Zookeepers at ZSL London Zoo had a lengthy task to conduct on Thursday as every animal “from the tallest giraffe to the tiniest tadpole” was measured as part of the annual weigh-in.

With more than 14,000 animals in their care and a variety of different personalities to take into account, keepers at the zoo used tactics to entice the animals to stand up and be measured.

These included “tricking” this year’s Humboldt penguin chicks into walking over scales one by one as they lined up for their morning feed, as well as encouraging Bolivian black-capped squirrel monkeys onto the scales with treats.

Keepers at the conservation zoo spend hours throughout the year recording the heights and weights of all the animals, and the annual weigh-in is a chance to ensure the information they have collated is accurate and up to date.

Each measurement recorded is then added to the Zoological Information Management System (ZIMS), a database shared with zoos all over the world that helps zookeepers to compare information on thousands of threatened species.

London Zoo’s 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.

Western lowland gorillas during the annual weigh-in at ZSL London Zoo (James Manning/PA)PA Wire/PA Images - James Manning

“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 co-ordinates the global programme for Sumatran tigers, for example.

“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.”

Humboldt penguins are weighed during the annual weigh-in at ZSL London Zoo (James Manning/PA)PA Wire/PA Images - James Manning

Several animals also made their debut at the annual weigh-in this year, including western lowland gorilla Kiburi, who arrived as part of a global breeding programme for the endangered species last November.

Zac and Crispin, a pair of critically endangered Sumatran tiger cubs who recently celebrated their first birthday, also saw their first weigh-in at the conservation zoo.

For the cubs, the weight check gives ZSL veterinarians and zookeepers important information about their development, with the team estimating it will not be long until the growing duo record the same vital statistics as their mother and father.