Adam Goldsmith
Reporting from London Zoo

Image source, EPA/Shutterstock

With the big result announced, that's our portion of the weigh-in concluded.

We only really got a small glimpse at the massive operation that goes on here in Regent's Park, with over 10,000 animals on site.

From lemurs to giant tortoises, we've seen how the keepers deal with the challenge of tempting some of the zoo's residents onto the scales. (Spoiler: it usually involves snacks.)

The rest of the Zoo's animals will be weighed over the next week, before results are shared with conservation organisations across the world.

Before I head off to pet an alpaca, a huge thanks to London Zoo's team who've shared their work with us this morning. Thanks for reading.

The first morning of London Zoo's annual weigh-in is coming to a close.

Here are some of our highlights:

First up, the bachelor ring-tailed Lemurs, who weighed an average of 2.5kg.

The slow but steady Galapagos tortoises, Polly and Priscilla, can weigh around 125kg each.

Priscilla just turned 30, and could live to be 150.

Finally, there are the capybaras, Gizmo and his sister Kiwi, who will grow to be bigger than her brother.

They can each weigh in at around 60kg.

Image source, Getty Images

• Guy the gorilla: Aptly named after arriving at the zoo on Bonfire night in 1947, Guy went on to gain fame for his gentle disposition, even appearing on children’s TV shows
• Winnie the bear: When an American black bear was deposited at the zoo in 1914, few could have predicted the legacy the animal would have. But, when author AA Milne visited the bear with his son Christopher Robin, Winnie is thought to have immediately become the inspiration for the hero of his children’s books, Winnie the Pooh

Image source, Getty Images

• Jumbo the elephant: Jumbo was London Zoo’s first African elephant. As he grew in size, he became a firm favourite with visitors, who were offered rides on his back around the site
• Obaysch the hippopotamus: Was the first hippo seen in the UK since prehistoric times when he arrived at the zoo in the 1850s

While animals at London Zoo have been taking part in an annual weigh-in, we've been asking you to guess which of these four options is the heaviest:

• 100 Humboldt penguins
• 5,000 magnolia land snails
• Two giant Galapagos tortoises
• 20 capybaras

And we can now reveal the results.

• Robin the Humboldt penguin weighed 4.9kg today, which makes 100 of them total 490kg
• The weight of a magnolia land snail is 129g, making 5000 of them a whopping 645kg
• Despite Polly tipping the scales, we now know a Galapagos tortoise weighs around 124kg. That makes two giant Galapagos tortoises around 248kg
• Together, capybaras Gizmo and Kiwi weigh 86kg. So 20 capybaras would weigh 860kg

The correct answer is 20 capybaras - which only 25% of those voting guessed correctly.

Image source, PA Media

Confident, not necessarily friendly, but definitely not camera shy - meet London Zoo's penguins.

Today’s weigh-in isn’t the only time that London Zoo assesses its animal population.

Back in January, zookeepers in Regents Park gathered their abacuses and counted the animals at the zoo’s annual stocktake.

This involves tallying up more than 10,000 individual animals - though the zoo has workarounds, like counting hives of bees as one to avoid the impossible task of monitoring dozens of buzzing bees.

The stocktake is a requirement of London Zoo’s licence, and like today’s weigh-in, can take a whole week to complete.

The records are then shared onto the worldwide database, which informs conservation programmes for endangered animals.

Image source, EPA

The scale is no stranger to the Zoo's Humboldt penguins, who have been practising weigh-ins all year round.

Their zookeeper, Jess Ray, tells us that the penguins have been getting accustomed to the scales since they were chicks.

That by no means makes it an easy job for Jess and her fellow zookeepers. They'll be weighing all 79 of the Zoo's penguins across a few days. The toughest of whom, is called Petal.

"She’s quite a shy penguin. She’s gotten more and more comfortable over time but she’s usually the tricky one," says Jess.

Humboldt penguins are typically found on the islands and rocky coasts of Peru and Chile.

Contrary to popular belief, only four of 18 penguin species live in cold climates full-time.

Capybaras, it turns out, love a bit of a scratch.

We've been hearing from London Zoo's Head Zookeeper, Dan Simmonds, who tells us the zoo's squirrel monkeys are the hardest to control on weigh-in day.

"Unlike the penguins who are fairly orderly, the squirrel monkeys queue barge," says Dan.

Sometimes they even try their luck with a double weigh in, in hopes for getting double the treats.

The monkeys are part of one of the 10,000 animals - across 400 species - being weighed at the zoo.

"We got in super early, we'll be here super late," Dan says.

Adam Goldsmith
Reporting from London Zoo

It's time for today's headline act.

You might have been checking in with the Humboldt penguins, who we've been featuring on our live page throughout the morning.

Now, we're going to hear from their keeper as the animals are weighed.

The zoo has saved these excitable residents for last on our media weigh-in tour, and they'll be raring to go as their measurements are taken during a fish breakfast.

And don't forget, you can follow all the action live at the top of this page.

Adam Goldsmith
Reporting from London Zoo

Though they may not have mastered balancing on scales, Galapagos tortoise dung plays a vital role in keeping the Galapagos Islands plants healthy.

By munching on plants, the tortoises then spread seeds across the islands, in effect planting them with their fertile dung.

And the animals' slow trampling through the environment also helps keep foliage under control.

Image source, Getty Images

... not very easily.

In fact, keepers at London Zoo will weigh leafcutter ants - some of their smallest residents - by taking a sample of the colony together to avoid testing their counting skills too greatly.

And, as London Zoo is home to more than 10,000 animals of all shapes and sizes, the task of weighing each species is a little more complex than wheeling around a set of bathroom scales.

Penguins, for instance, are tempted onto the scales with the promise of a fish breakfast as they queue for their morning feed.

Meanwhile larger animals like lions and gorillas can be patiently lured into stretching up trees to grab food, enabling keepers to measure their height.

And as our last post shows, it doesn't always go right on the day.

Adam Goldsmith
Reporting from London Zoo

Zookeeper Jamie Mitchell tells us that the scales for the tortoises failed today - just recording zero each time.

Not to worry though, we're told these tortoises average around 125kg, and the keepers will just try again later.

No loss either for Dolly, Polly and Priscilla who at least enjoyed a morning salad.

We're just getting set up for a chat with the zoo's head keeper Dan Simmonds - you can watch live on the stream.

Finished with her weigh-in, Polly has a brief wobble.

But she's back on firm ground in no time.

Adam Goldsmith
Reporting from London Zoo

Our next stop sees us join the Galapagos tortoises in their (very humid) enclosure.

It's fair to say they're less lively than the lemurs, but they're enjoying some salad before they hit the scales.

The keeper explains that one of the tortoises, Priscilla, is trained using a purple cone which she knows is a sign that food is on the way.

Priscilla just turned 30 this year, and could live to be 150.

Adam Goldsmith
Reporting from London Zoo

We're told the capybaras should weigh around 60kg, although both are still growing.

Their keeper says that the female Kiwi will actually grow to be bigger than her brother, Gizmo.

Around 65kg is an ideal weight for an adult capybara.

Up next for a weigh-in are the zoo's Galapagos tortoises.

For the "all boy bachelor group” of ring-tailed lemurs at London Zoo, it’s not the weightiest who runs the enclosure. Instead, it’s the smelliest.

Chelsea Reid Johnson, Lemur zookeeper, explains how male lemurs have “a stink fight” to decide mating rights.

“They produce a smell undetectable to human noses...and waft it towards other male lemurs as a form of competition,” she says.

That being said, Chelsea says Lemurs are generally laidback as an animal. Being food-motivated, it’s easy to get them to stay put on a scale - if you have some sweetcorn in hand.

While we wait for the next group of animals to hit the scales we want to hear your guesses on who you think will weigh the most out of some of the species being weighed today.

Is it 100 Humboldt penguins, 5,000 magnolia land snails, 20 capybaras or two giant Galapagos tortoises? Just scroll up this page to submit your guess.

As a reminder, you won't know the right answer yet - we'll bring you the correct guesstimate once the final measurements are tallied.

Adam Goldsmith
Reporting from London Zoo

Next up, we're taking a detour via the capybaras.

We're told these two - Gizmo and Kiwi - have become some of the most popular animals at the zoo.

Our reporter Lilah will be speaking to the rodent's keeper in a moment - watch live as she gets the lowdown.

Adam Goldsmith
Reporting from London Zoo

The lemurs are on the scales. Repeat, the lemurs are on the scales.

There's action in the enclosure as a few of the braver ring-tailed lemurs surround the Chelsea the zookeeper.

You can watch the lemur weighing live at the top of the page.