Travel | Sloths are slow for a reason

In Spanish, the word for sloth is “perezoso,” which means “lazy”. But during a recent trip to Panama, I discovered that their slow pace of life is in fact a perfect adaptation to their environment.

Panama sloths

Brown-throated sloths are found exclusively in Central and South America, and I was so excited when I got the opportunity to travel to Panama’s Caribbean coastline to study these animals up close. I stayed on the Isla de Bastimentos, part of the Bocus del Torro archipelago where I was a guest of Jim Kimball who owns an eco-lodge named Tranquilo Bay.

To book a similar trip to this follow the link to my travel page. Jim was keen to show me the wildlife that abounds in this region and couldn’t wait to take me on a tour of the rainforest to look for sloths.

As soon as we reached the edge of the dense jungle, Jim pointed out a sloth on a rock beneath a tall cecropia tree. I watched mesmerised as the sloth slowly began to climb the tree. A female, she was so close I could hear her claws digging in as she scaled the tree’s vertical trunk. The first thing that struck me was how quickly she reached the top.

Despite her apparently slow pace, which seemed almost dream-like as she hauled first an arm, then a leg, and so on up the tree trunk, it didn’t actually take her long to get there. Sloths have less muscle mass than animals of a similar size, and yet their grip is double the strength of a human’s which makes them extremely good at climbing. She made the 15-metre climb look easy.

A sloths diet is low in energy

Near the top, I watched her tear off a handful of tough, rubbery cecropia and begin, very slowly to chew a mouthful. It occurred to me that this diet is the cause of the sloth’s slow-paced lifestyle. Sloths are folivores, which means they feed exclusively on leaves. It can take up to two weeks for them to digest these in their multi-chambered stomachs and the sloths only eat a couple of handfuls a day.

With a diet that delivers so little energy, these animals need to expend as little energy as possible. And, since these creatures have been around for about 65 million years, it’s clearly lifestyle that works.

Baby sloths

The next day I was just leaving my cabana when I caught the sight of a baby sloth, tucked into its mother’s breast. Brown-throated sloths’ mate between January and March, and after a six-month gestation, females give birth to a single offspring. The mothers care for them until they reach independence, at about six-months old. This one was only about a month old and was not much bigger than my hand.

I watched fascinated as it slowly moved away from its mum and hung independently from a branch. Baby sloths are born with tremendous grip and use their long, curved claws to cling to branches or to their mother’s fur. After a short adventure, it returned to its mother and began to suckle. Baby sloths suckle small drops of milk throughout the day since the mothers need to keep their weight down so that they can climb more efficiently and so don’t store milk.

After a brief suckle the baby reached up and touched its mother’s nose and then they began licking each other. Interestingly the baby began licking at bits of leaf from around its mother’s mouth. Jim explained that by tasting food mum has eaten, the baby learns which trees are safe to eat from.

Green algae supplement

Next, I spotted a young sloth with a green tinge to its fur. This was actually algae and again is a fascinating adaptation to life in the treetops since the colour helps sloths to stay camouflaged in the canopy. But this isn’t the only benefit. Algae is also rich in fats and nutrients, which sloths are sorely lacking. And so, for the energy conscious sloth, the algae serves as a mobile larder.

I watched amused as it began licking its fur. Then the sloth did something even more interesting. Instead of defecating from the branches where it hung, it made the slow and dangerous journey to the rainforest floor. I learned later that a unique species of moth, known as the sloth moth, lays its eggs in the fresh dung and that this species has developed a surprising relationship with the sloths.

The moths live in the sloth’s fur where their presence promotes algal growth, ensuring the sloth has a constant supply of food on board. The more moths a sloth carries in its fur, the more algae and nutrients it has access to. Some sloths have more than a hundred sloth moths in their fur. This incredible symbiosis is key to the sloths’ unique lifestyle.

Mesmerised by sloths

Sloths usually rest during the warmest parts of the day, but as the temperature cools, they start to move and this was the best time to watch them. One evening a sloth came within metres of me. She seemed so oblivious of me as she slowly made her way through the trees, one branch at a time, a baby clinging tightly to her chest as she moved.

It felt extraordinary to be so close to a sloth in the wild and I almost had to duck as she reached for a branch close to my head before changing course and reaching for an alternative branch further away. I watched as she slowly moved off, stopping for a scratch, her baby mimicking her with its long talons. At one point she let go of her hold on the baby and the infant dangled upside down, hanging on to her fur with its long claws.

Watch my sloth video

I have seen sloths before, but I’d never seen anything like this and I stayed a long time just watching the pair as they slowly made their way through the canopy, dangling upside down as the mother munched on leaves. It was a true privilege to spend time with these amazing creatures and get an insight into their unique way of life.

And to think, many people think sloths are lazy, when in fact their slow pace hides some ingenious adaptations. Below is a video I made about this sloth experience.