All text and images by Roland Seitre*/naturepl.com *(unless otherwise stated)

When an orphaned three-toed sloth was brought to her doorstep over 20 years ago, little did Judy Avey-Arroyo know that her whole life was about to change. We find out how the arrival of this single baby sloth led to the creation of a world-renowned sloth rescue and rehabilitation centre.

Welcome to the Sloth Sanctuary!

Near to Cahuita National Park, on Costa Rica’s Caribbean coast, sits a peaceful wildlife haven, run by Judy Avey-Ar-royo and her family. After a professional life spent in Alaska, Judy and her husband Luis Arroyo settled in Costa Rica, to-gether with their daughter and grandchildren.

What started out their dream of a guesthouse for birdwatch-ers has transformed into a centre dedicated to one of the more unusual Costa Rican mammals: the sloth. The centre and its success all stems from a chance encounter in 1992 between Judy and an orphaned baby sloth called Buttercup, who instantly captured her imagination and affection.

Three young girls from the local neighbourhood found But-tercup and took her to Judy hoping she’d be able to help. Judy and her husband Luis took in the young orphaned sloth and set about looking after her. They contacted a number of zoos for advice but very little was known about how to rear baby sloths, so with lots of common sense and using leaves they saw wild sloths eating, they raised their first orphan sloth.

Two years later a local bus driver brought them another orphan and from there it escalated. As word got around that the Arroyos knew how to look after sloths, new arriv-als steadily increased and they became an authorized sloth rescue centre in 1997.

The Sloth Sanctuary, also known as Aviarios del Caribe, is now a specialist institution that provides visitors the opportunity to meet this intriguing creature. The centre is dedicated to the protection of the two Costa Rican sloth species – the brown-throated three-toed sloth, Bradypus variegatus (known locally as Ai) and Hoffmann’s two-toed sloth, Choloepus hoff-manni (known as Unau).

As well as the rescue and rehabilitation of sloths that are brought into the centre, Judy and her team study the centre’s residents and their wild neighbours in an at-tempt to better understand sloth behaviour, physiology and pathology.

Hoffmann’s two-toed sloth (Unau) Brown-throated three-toed sloth (Ai)

Photos © Suzi Eszterhas / naturepl.com

Research student, Rebecca

Cliffe attaching a ‘daily diary’

transmitter to a brown throated

three-toed sloth. This device is

used to monitor the daily activity

of wild sloths and will be used

to learn more about their

behaviour in the wild.

A rehabilitated brown throated three-toed sloth being released back into the wild by rescue worker, Santiago Chaggo

What started out as chance encounter with an orphaned baby three-toed sloth has developed into a fully authorised sloth rescue centre that has seen over 500 sloths pass through its doors.

Over twenty years on, Buttercup still welcomes visitors with her Mona Lisa smile, and watches over proceedings from her armchair suspended in the middle of the centre. She holds out a long arm to visitors, but with her three formidable claws, each 5cm (2 inches) in length; it’s not advisable to get too close!

Buttercup sitting in her wicker chairPhoto © Suzi Eszterhas / naturepl.com

The sloth is a creature of contrasts. At first glance its fur looks to be rough and spiky, but one stroke reveals it to be silky and smooth, and hiding a thin, delicate body. Despite its relatively large size, equivalent to a medium-sized dog, the average sloth only weighs be-tween 4 to 8 kg, more comparable to a large cat. And yet its strength is prodigious, an iron fist in a velvet glove!

It is quite impossible for a person to detach a sloth from the branch it is clinging to; even dead sloths have been known to retain their grip! Likewise, when feeling threatened, a sloth may grasp its aggressor and it is said that jaguars have perished in the vice-like em-brace of a sloth, even one injured by the cat. And if its strength wasn’t enough, a sloth’s claws are like deadly daggers and can easily pierce the skin.

Their claws

are effective both

as climbing-hooks and

as defensive weapons

against predators.

The sloths fur may look rough and coarse but is actually silky and smooth.

Buttercup meets

some of the young-

er residents at the

centre.

It takes the element of surprise to get around a sloth’s defences – something its main predator has mastered. Harpy eagles weigh the same as sloths, but have the advantage of flight and are capable of swooping down and snatching their prey from a branch before it has a chance to establish its grip.

Since sloths move slowly, their primary defence strategy is to remain hidden amongst vegetation. They are so sedentary that algae grows on their furry coats, giving them a greenish tint that affords them camouflage. The algae also provides a food source for insects, including a species of moth that eats nothing else!

DID YOU KNOW?

Despite their resemblence to

monkeys, sloths are actually most

closely related to anteaters.

Three toed sloths have extra

vertebrae which means they can

turn their neck almost all

the way round!

Photos © Suzi Eszterhas / naturepl.com

DID YOU KNOW?

Unlike most mammals the hair

of a sloth actually grows away

from their extremities. They

have developed this feature

to protect them from the ele-

ments while hanging upside

down.

In their evolutionary history sloths were originally ground-dwelling animals, feeding on leaves within easy reach of the forest floor before adapting to life in the trees, where they could be nearer to their food source.

Today, they feed, mate and give birth in the treetops, descend-ing to the ground every 5 to 8 days to defecate. This might seem rather infrequent, but because sloths digest as slowly as they move, food may take a month to pass through their system!

Sloths are typically clumsy on land. Their hind legs are too weak to hold them upright and their claws are a hindrance. They drag themselves along the ground, digging into the earth with their front claws.

Despite this, they are surprisingly good swimmers, sometimes dropping from their tree into rivers and swimming to new trees by using their long front limbs to propel themselves.

DID YOU KNOW?

Sloths only descend from

their trees about once a

week to go to the toilet!

Photo © Michael Pitts / naturepl.com

Photo © Suzi Eszterhas / naturepl.com

Sloths are often depicted hanging beneath a branch, but in fact they only use this position in order to move or to feed. The rest of the time they sit upright as, like all terrestrial mammals, their digestive tract functions far better with the stom-ach below the mouth!

In order to aid digestion they can often be ob-served basking in the sun, which raises their body temperature and enables more efficient digestion, with minimal effort. Unusually for mammals, a sloth’s body temperature can often fall below 30∘C so their “siestas” in the sun are vital.

There are two groups of sloths, containing half a dozen species liv-ing in jungle habitats of Central and South America, from Mexico to Argentina. The two-toed sloths (Choloepus species) moved into the trees more recently in evolutionary terms and have a varied diet including leaves, buds, shoots and fruit.

Conversely, the three-toed sloths (Bradypus species) adapted first to an arboreal existence. They are true leaf specialists and exclu-

sively vegetarian. They are also less active and slower-moving.

With the limitless supply of foliage in their jungle homes, three-toed species face less competition for resources than their two-toed cousins. In some areas, they are so abundant they represent half of the mammal biomass, despite being rarely seen.

DID YOU KNOW?Because their body tem-perature fluctuates with

the external temperature sloths are constrained to life in the tropics.

Scientists have long known that sloths eat the leaves of hundreds of different tree species. But what Judy and her researchers have dis-covered, through their efforts to help injured animals, is the high degree of specialisation within individual sloth families. In general, a particular individual will eat less than a dozen varieties of plant and the choice of plants var-ies from one family line to another.

A mother sloth teaches her baby which leaves to eat, at which stage and quantities they are safe to consume (as toxicity tends to vary with the age of the leaf and certain doses can be poisonous) and even exactly where the edible trees are situated within her territory. This ap-prenticeship normally lasts about a year and without it the baby sloth would not be able to survive.

After many attempts, Judy has given up trying to reintroduce babies that have been brought up at the centre back into the wild. Injured adults whose wounds have healed pose no problems, but to release a baby into the wild which has lived for less than six months with its mother would, according to her, lead to a certain death sentence.

Junior, one of those she released, stayed for four or five days high up in one tree, before returning to the centre to seek food, and then disappear-ing. Zephyr, released close to the centre at the age of two and a half, did not stop eating for eight days and, intoxicated by excessive ingestion of tannins, sadly returned to die in their arms. Oth-er sloth centres in the Americas claim to have achieved successful reintroductions, but accord-ing to Judy they have not tracked the animals suf-ficiently to confirm the success of this operation.

Photos © Suzi Eszterhas / naturepl.com

Young sloths learn all about which plants are safe to eat from their mothers

There are currently about 150 sloths living at Aviarios del Caribe, the youngest is barely 3 weeks old and weighs just 200 grams, half of the normal birth weight.

“To rear a sloth born so prematurely rep-resents a real challenge, but I have to try”

says Judy, covering the tiny animal in kisses. With great care, she inserts the end of a sy-ringe filled with warm goat’s milk into the baby sloth’s mouth, which immediately starts to suckle.

Its mother was severely burned attempting to cross a road via an electric cable. One of her arms had to be amputated and the shock caused her to give birth prematurely to a baby that was just viable, but which she was unable to bring up. Judy stepped into the breach right away, feeding the infant with a tiny baby’s bottle every 2-3 hours, day and night.

“We have around 20 sloths aged between two and four months, which need bottle-feeding every three hours, before they can be gradual-ly weaned.”

Keeping operations running smoothly at the centre is full-time work for fourteen people, including Costa Rican locals and volunteers from all corners of the world.

They take on the role of adoptive mothers, while also giving the centre’s visitors, whose entry fees finance this work, a detailed pre-sentation of their work.

Looking after all the

sloths is full time

work for the team of

staff and volunteers

at the centre.

Photos © Suzi Eszterhas / naturepl.com

[Above] Volunteer exercising young two-toed sloths. [Above] Volunteer observing the brown-throated three-toed sloths.[Below] Hoffman’s two-toed sloth on climbing frame. [Below] Judy Avey-Arroyo, sloth refuge owner, with Hoffmann’s two-toed sloth.

Time for a check up!

One of the centre’s two-toed

sloth being weighed and

measured. All data is care-

fully recorded to monitor

individuals’ growth.

Mealtimes at the centre are quite a logistical feat. For one of the three large daily meals, a big table is covered with a thick comfortable cloth, on which the baby sloths are placed. The largest ones receive a plate of fresh veg-etables, carrots, green beans, local spinach leaves, which they can pick up with their hands and place in their mouth.

The slightly younger, less capable sloths are helped by the centre’s staff and volunteers, who guide thinly sliced vegetables in their mouths, to nibble at their leisure. Any sloths under the age of one also receive a helping of milk before their vegetable course.

The youngest sloths have to be content with a bottle of goat’s milk, the only food they can consume. Unfortunately it is almost impos-sible to find locally, so it has to be illegally imported from the USA - a constant headache for Judy. After the bottle, the baby sloths are given a mixture of stewed leaves to lick, which helps with the weaning process.

“As you see, it’s impossible to provide the nec-essary knowledge and detail of wild plants sufficient for the babies to be released” Judy explains.

Meal

times are quite

an organisational feat!

The age of the sloth deter-

mines what food they get;

whether it’s goats milk,

stewed vegetables or

slices of carrot.

DID YOU KNOW?All sloths have three toes on their back feet; it is only the number on their front feet that varies.

DID YOU KNOW?Community outreach and envi-ronmental education is an im-

portant element of the work done at the sloth sanctuary, making

people aware how habitat loss and power lines are threatening

the local sloth populations.

Because they cannot be reintroduced to the wild, the baby sloths live with adoptive mothers in a specially adapted enclo-sure, where they will live a long and happy retirement. They are organised into same-sex groups of two or three, in order to avoid any reproduction.

Certain animals are shown to the public daily in a large build-ing devoted to education. Various support materials, includ-ing a DVD and a small museum, are also used, but nothing is as effective as the authentic experience of seeing close up the charm and gentleness of these unique animals.

For more information contact Laura Sutherlandlaurasutherland@naturepl.com

A gallery containing all the images from this story can be found here.