Hairy animal holding a tree trunk
Animals,  Birds,  Costa Rica,  Lens-Artists

The oddities of sloths

Is there a mammal more intriguing, cute and downright odd than a sloth? They spend so much time hanging around in trees that they start to look like them. That makes them quite hard to spot, and even harder to photograph!

To give ourselves the best chance of seeing them we booked a tour in the Arenal area called ‘Sloths and Toucans’; this promised us a good look at these most iconic of Costa Rican species.

Our guide Edson took us first to an area beside a river which he described as a sort of sloth corridor. Along the footpath we came across quite a few sloths in the trees; or rather Edson did, as he knew just where to look. Sloths don’t travel around much, and he knew their favourite trees and hiding places. He had a name for each one: Raoul, Ronaldo, Walter, Rebecca, Scarlet. Many were sleeping and all we saw was the ball of fur, but a few showed their faces!

Hairy animal sleeping on a branch
A ball of fur

As we walked between sightings, and while we waited for sloths to move (!) Edson shared some interesting facts.

Firstly, although the two types of sloth are known as two-toed and three-toed, they actually both have three claws, or ‘toes’, on their hind limbs. It would be more accurate to call the ‘two-toed’ sloth a ‘two-fingered’ sloth, as the difference between them both can be found only on their front limbs. They are actually quite distinct species but have evolved similar characteristics and habits.

Hairy animal hanging from a branch
Two-fingered sloth

One reason they are so hard to spot is all the algae on their fur. They have a symbiotic relationship with this. The sloth provides the algae with shelter and water (sloth fur is highly absorbent); meanwhile the algae provide the sloth with camouflage. Sloths’ fur also supports an entire mini-ecosystem, including several species of moths and beetles found nowhere else on earth!

Hairy animal in a tree
Three-fingered sloth

And did you know that the fastest a sloth ever gets is while mating? They can accomplish this in just five seconds according to Edson! I was struck when I read the other day on a post from Dianne, the Rambling Ranger, that,

‘When it comes to sexual endurance, the Monarch Butterflies put humans to shame. A pair of Monarchs will mate for up to 15 hours! They start mid-afternoon and finish shortly after sunrise.’

Who would have guessed that between a flighty butterfly and an almost soporific sloth, it would be the latter that does it in just five seconds while the butterfly takes 15 hours!

Another of Edson’s facts was that the mother gives birth up her tree, shooting the baby out on the umbilical cord so he/she hangs like a bungee jumper before being hauled up to cling to her fur.

Hairy animals in a tree
Sloth and baby

Sloths are also quite nippy on their once-a-week descent to the ground to poop, as it’s much riskier down there for them. One of the other guests asked why they don’t just do this in their tree; Edson explained that this would leave a scent that would make them easier for predators to find, so they need to climb down and bury their poo. I’ve read another theory online however; that the poo marks out their tree for potential mates to find.

And he told us that they swim much faster than they walk; and he showed us a video on his phone that he had taken of a sloth swimming.

Hairy animal hanging from a branch
Three-fingered sloth – my favourite of the photos I managed to get

Talking of phones, not only did I get quite a few photos myself, Edson cleverly took photos on some of our phones through his telescope with excellent results. Here are a few of his shots; spot the bonus iguana in one of them!

When I saw a few days ago that Tina’s theme for the Lens Artists challenge this week was to be Odds and Ends, I assumed, wrongly, that she would be asking us to share images of odd things. I thought immediately of these cute but decidedly odd creatures. It turns out, however, that what she is looking for is odd photos, that have never really fitted a challenge. Well, because quite a lot of my posts aren’t linked to any challenges, I don’t really recognise that as an issue; any of my shots has the potential to make it into a post at some point. So I’m taking the liberty of going ahead with my original plan even if it isn’t quite what Tina intended!

As to the ‘Ends’, after our walk along ‘Sloth Alley’ we drove to another area where we ended our tour with a sighting of two toucans, a Collared Aracari Toucan and a Yellow-throated Toucan.

Bird with large beak and yellow and red breast
Collared Aracari Toucan
Large mainly black bird with big beak and yellow throat
Yellow-throated Toucan

I visited Costa Rica in February 2022


  • Leya

    Sarah, thank you for this excellent post! I too learned from sir David first, but you did it so well – and the photos were all brilliant. Your favourite is mine as well – it is so difficult to get their faces! You had a great tour, I understand, and a good guide is essential here. Costa Rica would be a dream for me, I know, but I cannot stand the heat and the humidity, so – thank you for the virtual tour, it really made my morning ♥

    • Sarah Wilkie

      Thanks so much Ann-Christine 🙂 We were very pleased with almost all our guides in CR – only one let us down a bit as he seemed only interested in showing us trees on our night walk whereas we hoped to see night creatures (but he did find us two tarantulas!) Inland the country isn’t too hot – we had around 20 degrees in Monteverde, 26 in Arenal. But it can be humid, yes, and the coast was very hot – too hot for me in the north west at around 32!

  • Marie

    Ah you did so well…. Good idea to take a specific tour. I’ve one or two photos of sloths but only I know what I’m looking at!!!! Your favourite is also my favourite. Such odd creatures!

  • Smitha V

    I’m so glad I read this post.It has such a wealth of information and so interistingly put. i had no idea about the fur having algae growing on it or the mating or sloths coming down once a week to poop. Thank you for sharing this, Sarah. I’m sharing your post.
    The sloth on a tree (where the face isn’t visible) looks like big nest. It’s fur looks like the husk of a coconut.

    • Sarah Wilkie

      The structure of their faces is such that they always look like their smiling but of course that’s us projecting human behaviour on to animals! But it does make them look cute!

  • restlessjo

    It occurs to me that I knew nothing about sloths till I read this, Sarah. What I now know is that I wouldn’t much like to be one. Thanks for a very enlightening article.

  • pattimoed

    Fascinating post, Sarah, of this shy and eccentric creature. I’m still pondering their habit of climbing down the tree once a week to poop and the fact that they have algae living symbiotically on their fur. Odd indeed and fascinating. 😀😀

  • Tina Schell

    Well it may not match what I intended Sarah but it’s a terrific post about, yes, a very odd animal (but not to another sloth I expect!). Had no idea they had algae on their fur, plus they house other critters in it – yikes! Happy to have given you an opportunity to share this one!

    • Sarah Wilkie

      Gosh, no, or at least I can’t imagine that they are. Maybe if you mishandled one it would scratch you with those long claws, but they’re far too slow to be a threat and they’re herbivores so don’t hunt prey.

  • maristravels

    How on earth …..? But I know how, patience and a good guide. I only managed to get a so-so picture of a sloth when I was in Costa Rica and I have to point it out to people as otherwise the’yd miss it. Your images are brilliant but what we’d expect from you. And yes, the sloth is definitely odd.

    • Sarah Wilkie

      Yes, the good guide is key. I wouldn’t be at all surprised to learn that on the one occasion we did a walk in one of the reserves on our own, unguided, that we missed several sloths! Thanks so much for the kind words about the photos, but you should see how many of my attempts were completely unpublishable 😆

  • Sandy

    Interesting facts Sarah. I was marveling at your photos and your incredible close-ups. I figured you were very agile in climbing trees 🙂 or had a very good zoom. It’s a very good tip to use the telescope & phone camera. I’m guessing it’s a lot lighter to carry than big lens

    • Sarah Wilkie

      My photos were all taken with my zoom – no tree climbing was involved 😆 And I discovered that the trick with using a phone with the telescope is that the phone’s lens is small enough to line up with the viewing circle of the telescope. Clever stuff!

  • lisaonthebeach

    Sarah, this is a wonderful post! I love the photos, and the interesting facts and info. Fascinating! I had no idea they had algae on their fur. What a fun adventure! 🦥🦥🦥

  • Alli Templeton

    Fascinating, Sarah. They’re wonderful and intriguing creatures, and I’ve learned some surprising stuff about them here. ‘Oddities’ is the word for them, but lets face it – they’re incredibly cute with it! You’ve gotta love ’em!

    Great photos, as always, and what a boon to finish with such a good view of the toucans. 🙂

    • Sarah Wilkie

      Thank you Alli. They are cute, but that can be a disadvantage at times. In some places (not in Costa Rica, as far as I know) locals capture a sloth and charge tourists to pose with it, and because the animal looks as if it is smiling the tourists think it is happy and well looked-after when the opposite is true 🙁

      And you’re right about the toucans. They were proving elusive but late in the tour we found these two!


    They were just brilliant to see, weren’t they, Sarah? Just standing staring at them was great, watching their slow movement even better. On the subject of copulation endurance (oh sorry about that phrase!), we also saw a species of frog where the female is hugely bigger than the male. This is due in part to the fact that she has to carry the male on her back while insemination takes place…and it takes 48 hours! The things you learn huh…

    • Sarah Wilkie

      Oh yes I loved them – although we didn’t see much slow movement apart from some languid turning of the head! That frog sounds amazing and makes nonsense of the comment by Michael (CliffClaven) that 5 seconds and 15 hours are the outliers 😆

  • Easymalc

    I love this post Sarah, not just because you’ve captured some wonderful shots of one of my favourite animals, but also because I’ve become one 🙂

  • CliffClaven

    I guess that 5 seconds and 15 hours are the outliers. Apart from that, it is perhaps better to offer no further comment! I thought of having a rummage in the cellar in the hope of finding some photos of the sloth I encountered in Panama many years ago. But then I thought: “Why bother? Sarah’s photos are so much better!”
    Congratulations on another great read.

  • margaret21

    Oh fabulous. Who doesn’t love a sloth? Or a toucan? And you’ve given me more odd information about sloths in an afternoon than I’ve previously had in my entire life.

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