Ahead of International Sloth Day (20 October), Guinness World Records is pleased to announce the oldest sloth in captivity. At the grand age of 50, a Linne’s two-toed sloth called Paula from Germany has been crowned with the title, being the oldest known of her kind. 

Other than some signs of age in her fur and nails, Paula is still very healthy despite her advanced age

Hailing from South America, where she was captured in the wild (a practice no longer endorsed by zoos), Paula has resided at Halle Zoo in Saxony-Anhalt, Germany, since 1971. Fully grown when she arrived there, she was conservatively estimated to be at least two years old at the time.

That means that in 2019 (Halle Zoo has nominated 14 June as Paula’s official birthday), she celebrated her big 5-0. In human years, that's the equivalent of around 90 years of age. 

This super-senior sloth has reached more than double the typical lifespan of two-toed sloths in the wild (20 years) and has also far exceeded the standard captive age range of 30 to 40. 

"There is no known sloth anywhere in the wild or in captivity that's clocked up more years," said Jutta Heuer, who keeps the official studbook for two-toed sloths in Europe.

Paula enjoys some of her favourite food – sweetcorn – with former curator of Halle Zoo, Jutta Heuer

As the former curator at Halle Zoo, the now-retired Heuer has also built up a close relationship with Paula over many years. 

"Paula is still fine, but you can see she is old," Heuer continued. "The hair is light and not so compact. The claws grow in different ways – the same as with elderly people. Of course, she moves slowly and is very relaxed."

"Paula's favourite foods are cooked or milk corn, cooked eggs and sweet fruits. She will follow you [as fast as she can] to get these!" Jutta Heuer, European studbook keeper for two-toed sloths.

Interestingly, Paula hasn’t always gone by that name. Over her first 20 or so years at Halle Zoo, she went initially by Faultier ("Sloth" in German) and then later as Paul, for she was believed to be a he

It was only when the staff performed an ultrasound scan in 1995 that they discovered the true sex of their erstwhile male sloth. It went a long way to explaining why the breeding programme hadn’t seen any success! 

"We were very surprised!" Heuer said of Paula's gender revelation. “This was the reason that I started the studbook. We found out that many zoos didn't know for sure as they could only trust the dealers' word. 

The discovery that Paula was female, rather than male, was made while undergoing an ultrasound scan in the 1990s

"Even now, it is still not easy to identify whether a sloth is male or female. We now sex sloths using DNA taken from hair samples."

Sadly, even when Paula’s true identity came to light and she was partnered with a male sloth, babies were not to be. Although Paula has been pregnant on three occasions, none of the cubs have survived. 

While Paula's age is exceptional, it’s not hugely uncommon for this species to make it past 40 years old. For instance, the next two oldest known sloths after Paula are coincidentally at another German zoo. Krefeld Zoo in North Rhine-Westphalia is home to 46-year-old Jan and 45-year-old Lulu, both of which are also Linne’s two-toed sloths. 

Asked why she thinks Paula has reached such a superlative age, Heuer told us: "I think stable conditions (e.g., temperature, humidity, food etc) without stress are responsible for her long life. It also comes down to caring staff – some of the keepers have known her for more than 30 years! 

"She lives together with a breeding pair [of sloths] and a group of night monkeys. There is no stress within the group."

Paula hanging out with her room-mates, two fellow sloths and a pair of night monkeys

More sloth records 

Slowest mammal 

Everyone knows that sloths aren’t the speediest of creatures, but did you know they claim a record among all mammals? Three-toed sloths have an average ground speed of just 1.8–2.4 m (6–8 ft) per minute – that’s 0.1–0.16 km/h (0.07–0.1 mph). However, when in their element in the treetops, they can reach "blistering" speeds of 4.6 m (15 ft) per minute, or 0.27 km/h (0.17 mph). 

Largest sloth ever 

To meet the all-time biggest sloth, you’d have to travel back in time to the Pleistocene Epoch, which began some 2.6 million years ago. The Florida ground sloth weighed in excess of 5 tonnes (11,000 lb) and, when standing on all fours, it was taller than an adult male African bush elephant. 

Smallest sloth 

With a head and body length of only 50 cm (20 in), the pygmy three-toed sloth is the smallest member of the sloth family. With only around 100 of them left, exclusively found on a single island off the coast of Panama, this critically endangered species is also the rarest sloth.

ZSL Edge of Existence conservationist Nisha Owen with a pygmy three-toed sloth on Isla Escudos de Veraguas, Panama

To meet more record-breaking animals, as well as some other superlative seniors like Paula, get your copy of Guinness World Records 2020, out now in shops and online.

Guinness World Records 2020