ELTON THE OWL and Dirk the tortoise were among the 16,000 animals being weighed and measured by keepers at London Zoo today.

The annual weigh-in began this morning with staff grabbing the scales and measuring tape to begin the long monitoring process.

Every animal – no matter how big, small, young or old – has to have its height and weight recorded. The measurements are catalogued into the Zoological Information Management System, which is then shared with other zoos around the world.

“This information helps us to monitor their health, their diets and their general well-being,” explained director David Field. “By sharing it with other zoos and conservationists, we can use this knowledge to protect wild animals, and use it to assess their health, their behaviours and even their ages.”

Adrian Walls added that the sex of some birds and animals can be distinguished by measuring certain parts of the body. “We can tell the sex of a flamingo by the length of its leg,” he told BBC Radio 4. “Females have shorter legs than the males.”

Walls said the most difficult animals to monitor are the large cats, such as the lions, and the giraffes.

“It’s not the easiest task to do,” he admitted. However, some creatures are open to a bit of bribery.

“Some of the penguins don’t like jumping on the scales but we can bribe them on there with a bit of fish or a tidbit.”