STORY: Penguins, tortoises, capybaras and lemurs hit the scales at the London Zoo for the annual animal weigh‑in on Tuesday (August 19).

“We’ve got over 10,000 animals across more than 400 species... in many cases we weigh some of the animals every single day... the difference with today is that it’s a formalized process where all of those weights get recorded onto an international database," said Dan Simmonds, the zoo’s animal operations manager.

The zoo’s four-metre-tall giraffe tips the scales at around 700 kg, while leaf-cutter ants are measured by the colony, he said.

The trickiest customers? “Always the monkeys," Simmonds said.

"They know that if they queue-barge or try and get in the queue twice, they’ll get a treat twice. But the keepers are on it.”

DESCRIPCIÓN DE IMÁGENES

Penguins, tortoises, capybaras and lemurs hit the scales for London Zoo’s annual weigh‑in

VIDEO SHOWS: ANNUAL ANIMAL WEIGH-IN AT LONDON ZOO / PENGUINS, TORTOISES, CAPYBARAS AND LEMURS ON THE SCALES / SOUNDBITES OF ANIMAL OPERATIONS MANAGER AT LONDON ZOO, DAN SIMMONDS

RESENDING WITH COMPLETE SCRIPT

SHOWS: LONDON, ENGLAND, UNITED KINGDOM (AUGUST 19, 2025) (REUTERS - Access all)

1. VARIOUS OF HUMBOLDT PENGUINS JUMPING ON SCALES / ZOOKEEPERS PLACING TREATS ON SCALES

2. GALAPAGOS GIANT TORTOISE APPROACHING SCALES

3. TORTOISE STEPPING ON PLATFORM ON TOP OF SCALES

4. TORTOISE EATING TREAT

5. (SOUNDBITE) (English) ANIMAL OPERATIONS MANAGER AT LONDON ZOO, DAN SIMMONDS, SAYING:

"Today's a big day. It's the annual weigh in. Now here at the zoo we've got over 10,000 animals across more than 400 species. So keepers have been in since six o’clock this morning, they'll be here, till gone six o’clock tonight when light even starts fading. The reality is, though, that we actually weigh the animals a lot more than just once a day (year). In many cases we weigh some of the animals every single day. The difference with today, though, is that it's a formalized process where all of those weights get recorded on to an international database called ZIMS, the Zoological Information Management System. We then share that with other zoos globally, with other conservation organizations, with all of our staff working out in the field on incredibly important conservation projects around the whole world.”

6. TORTOISE STEPPING ON PLATFORM ON TOP OF SCALES

7. TORTOISE AND ZOOKEEPER

8. CAPYBARAS

9. ZOOKEEPER FEEDING CAPYBARAS ON SCALE

10. ZOOKEEPER AND CAPYBARA

11. (SOUNDBITE) (English) ANIMAL OPERATIONS MANAGER AT LONDON ZOO, DAN SIMMONDS, SAYING:

"Largest animal today will definitely be one of our giraffes, Molly, four meters tall, not difficult to weigh. It's a whopping 700 kilos. All the way down to the smallest animal, which will be at leaf-cutter ant at just five milligrams. The reality is, we will weigh an entire colony. We're not going to weigh them all as individuals. Trickiest? Always the monkeys, probably most particularly the squirrel monkeys. They know exactly what they're doing. They know that if they queue barge or try and get in the queue twice, they'll get a treat twice. But the keepers are on it. The keepers will get a weight for every single animal, including all of the squirrel monkeys today.”

12. RING TAILED LEMUR JUMPING ON SCALE

13. ZOOKEEPER GIVING LEMURS ON SCALE TREATS

14. LEMURS EATING TREATS

15. ZOOKEEPER AND LEMURS ON SCALE

16. (SOUNDBITE) (English) ANIMAL OPERATIONS MANAGER AT LONDON ZOO, DAN SIMMONDS, SAYING:

"So we've got lots of tricks up our sleeves to get the animals weighed. Sometimes we'll modify the weigh scales, sometimes we'll give special treats from their diets, so their favourite fruit in the case of a monkey, or perhaps the juiciest possible piece of meat for the Asiatic lions. We’ll always make sure that not only the animals enjoy it, because they really do, but we'll make sure it's done efficiently and quickly because we’ve got a lot of animals to do in one day.”

17. VARIOUS OF PENGUINS

18. (SOUNDBITE) (English) ANIMAL OPERATIONS MANAGER AT LONDON ZOO, DAN SIMMONDS, SAYING:

"This is real science, we’re a science-led organization and for example, the science, the data that we will gain today, we will use to feed back into our projects in the wild. So for example, we will be able to weigh a Sumatran tiger. Now the sad reality is that if you go to the wild, you're going to struggle to see a Sumatran tiger because numbers are so low. But on those rare occasions where we do and in cases where a veterinary intervention is required for an injured wild Sumatran tiger, the vets all need to know, for example, what is the typical weight of a Sumatran tiger? And they'll look to zoos for that information. They'll look to London Zoo for that information. So a direct link between the value of days like today and active living conservation projects out in the field.”

19. VARIOUS OF SWIMMING PENGUINS