Animals at London Zoo are being checked and measured as part of its annual weigh-in day to monitor their health and wellbeing.

Zookeepers will need to coax every bird, reptile, fish and mammal - from the largest rodents in the world to the greenest katydids - to the weighing scale.

Each measurement is added to the Zoological Information Management System (ZIMS), a global database shared with animal carers and conservationists that compares important information on thousands of endangered species.

Many of the zoo's animals are trained to perch on a scale while zookeepers note down their measurements, but others will need to be tempted with a strategic snack.

Although the zoo houses more than 14,000 animals, the keepers will only have time to measure and log the weight of about 400 creatures.

Daniel Simmonds, London Zoo's animal operations manager, said: "Regular weigh-ins help zookeepers track the health of our animals, including invertebrates like the magnolia land snails, the capybaras and Humboldt penguins, and genuinely help us manage the care of these animals, who play a vital role in our global conservation efforts."

Among the animals weighed this year were capybara siblings Kiwi and Gizmo.

Kiwi weighed in at 45kg (7st), while her brother Gizmo tipped the scales at 50.5kg (8st).

While Giant Magnolia Land Snail No 2 weighed a modest 102.5g (3.6oz).