March of the penguins: London Zoo helps gauge animals' health

A penguin steps on scales during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

LONDON (Reuters) - London Zoo hosted its annual weigh-in for more than 20,000 animals on Thursday, dangling food above lions and placing scales in front of penguins to get them to walk onto them.

Used as an opportunity to keep the zoo's records up to date, the measurement and documentation process takes many hours and zoo keepers.

Meat is placed above the lions to get them to stand on their hind legs, while penguins are lured onto the scales with food.

A penguin steps on scales during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

    The data is then shared with zoos across the world.

"By sharing information with other zoos and conservationists worldwide, we can all use this knowledge to better care for the endangered species we're striving to protect," said Mark Habben, the zoological manager at ZSL London Zoo.

    The monitoring of the animals is useful for the zoo's commitment to protecting endangered species, while pregnancies can also be spotted with a "growing waistline".

A lion stand by a large ruler during photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

Just last May a spiny hill Turtle was born at the zoo, described by the International Union of Conservation for Nature (IUCN) as endangered.

(Reporting by Oliver Povey, editing by Elizabeth Piper)

Squirrel monkeys step on scales during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

A worker cleans the windows of a penguin tank during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

Lions stand by a large ruler during photo-call for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

A spiny turtle stands on scales during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

Gorilla sits next to a ruler during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

A fleas flying tree frog sits on a photographers lens during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall

A fleas flying tree frog sits on scales during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. REUTERS/Neil Hall