The ZSL Whipsnade Zoo is in the middle of its annual weigh-in which involves 9,500 animals jumping on the scales, with every animal from rhinoceroses to butterflies taking part.

The park, which is based in Dunstable and is the UK’s largest zoo, uses the figures as a way to keep track of the health and wellbeing of the animals.

But the task is no mean feat, with all creatures great and small coaxed into being measured.

The greater one-horned rhinoceros Beluki – who is one of the heaviest animals at the zoo – stepped onto an industrial-sized scale and weighed in at 259 stone (1,650kg).

Meanwhile, some of the smaller inhabitants, like butterflies and spiders, required extra sensitive equipment to weigh them accurately.

Heidi the reindeer was particularly reluctant to take part, while 1-year-old scarlet macaws Haribo, Skittles and Sherbert, swooped straight onto their special weighing perch.

Amur tigers, squirrel monkeys and otters all took part, as well as the Przewalski horse – which is extinct in the wild.

In one shot of the event, a group of penguins can be seen clamouring around the grass-covered scales, while an attendant feeds them fish.

In another snap, a reindeer can be seen standing obediently on a scale disguised as a wooden plank, while two keepers hold out some leaves for it to graze on.

For the tiny butterflies, a helper holds out a ruler to record the size of the colourful insect.

The animals’ weights and measurements are recorded in a database called Zoological Information Management System (ZIMS), which helps zookeepers around the world compare important information on thousands of endangered species.

Zoological manager Matthew Webb said: “All of our animals at ZSL Whipsnade Zoo are weighed and measured regularly, but the annual weigh-in is an opportunity to review the information we’ve recorded, and ensure it is up-to-date and accurate.

“With so many animals with different personalities, the zookeepers have to come up with creative tactics to entice them onto the scales, from luring Northern rockhopper penguins onto scales in exchange for their favourite fishy snacks, to encouraging our ring-tailed lemurs to bounce onto the scales for a tasty reward.”

As well as a gauge of the animals’ well-being, keepers use the regular weight checks and waist measurements to identify pregnant animals – many of which are endangered species that form part of the zoo’s international conservation breeding programmes.

The ZSL Whipsnade Zoo is in the middle of its annual weigh in – which involves 9,500 animals jumping on the scales, with everyone from rhinoceroses to butterflies taking part.

The park, which is based in Dunstable and is the UK’s largest zoo, uses the figures as a way to keep track of the health and wellbeing of the animals.

But the task is no mean feat, with all creatures great and small coaxed into being measured.

The greater one-horned rhinoceros Beluki – who is one of the heaviest animals at the zoo – stepped onto an industrial sized scale and weighed in at 259st (1650kg).

Meanwhile, some of the smaller inhabitants, like butterflies and spiders, required extra sensitive equipment to weigh them accurately.

Heidi the reindeer was particularly reluctant to take part, while one-year-old scarlet macaws Haribo, Skittles and Sherbert, swooped straight onto their special weighing perch.

Amur tigers, squirrel monkeys and otters all took part, as well as the Przewalski horse – which is extinct in the wild.

In one sweet shot of the event, a group of penguins can be seen clamouring around the grass-covered scales, while an attendant feeds them fish.

In another snap, a reindeer can be seen standing obediently on a scale disguised as a wooden plank, while two keepers hold out some leaves for it to graze on.

For the tiny butterflies, a helper holds out a ruler to record the size of the colourful insect.

The animals’ weights and measurements are recorded in a database called Zoological Information Management System (ZIMS), which helps zookeepers around the world compare important information on thousands of endangered species.

Zoological manager Matthew Webb said: “All of our animals at ZSL Whipsnade Zoo are weighed and measured regularly, but the annual weigh-in is an opportunity to review the information we’ve recorded, and ensure it is up-to-date and accurate.

“With so many animals with different personalities, the zookeepers have to come up with creative tactics to entice them onto the scales, from luring Northern rockhopper penguins onto scales in exchange for their favourite fishy snacks, to encouraging our ring-tailed lemurs to bounce onto the scales for a tasty reward.”

As well as a gauge of the animals’ well-being, keepers use the regular weight checks and waist measurements to identify pregnant animals – many of which are endangered species that form part of the Zoo’s international conservation breeding programmes.