London Zoo animals sized up at annual weigh-in
Ten-week-old penguin chicks and 80-year-old tortoises are just some of the huge variety of animals that have had their vital statistics recorded at ZSL London Zoo's 2015 annual weigh-in.
With more than 17,000 animals to weigh, the mammoth task is carried out on a regular basis by zookeepers as a way of keeping track of every animal's health and wellbeing.
Each measurement is then recorded into the Zoological Information Management System, a database shared with zoos all around the world, helping zookeepers to compare important information on thousands of endangered species.
The annual weigh-in is an opportunity for zookeepers at ZSL London Zoo to make sure the information they have recorded is up to date and accurate.
With different behaviours, personalities and traits to take into consideration, zookeepers use ingenious tactics to entice the animals in their care to stand up and be measured; getting penguins to walk over scales as they line up for their morning feed and training tortoises to clamber on to scales hidden in their grassy paddock.
As well as a key gauge of the animals' general wellbeing, keepers can also use regular weight checks and waist measurements to identify pregnant animals, many of which are endangered species that are part of the zoo's international conservation breeding programmes.