First Creature Feature: The Two-Toed Sloth!

Greetings from the rainforest! I've decided to feature an animal once a week that I'm working with and write up what I've learned about their biology, behavior, and the little quirks that every animal has. Hopefully it will be an effective way to communicate information about species that not everyone encounters on a daily basis.

A two-toed sloth chowing down on a carrot.

This week, I've decided to feature the two-toed sloth (Choloepus hoffmanni), also called the "peresozo de dos dedos" in Spanish (this literally translates to lazy with two fingers). Two-toed sloths are one of the two species of sloths found in Costa Rica; the other species is the three-toed sloth. These names are misleading, because the difference between the two species technically lies in their number of fingers, not toes. All sloths have three toes, but the two toed sloth has two fingers. I'm not sure who decided on such a misleading common name, but they may have been translating from Spanish, where dedo refers to both fingers and toes collectively. The three-toed sloth is diurnal, meaning that they are active during the day, but the two-toed sloth is active at night, or nocturnal. Both species feed mostly on leaves, but will also eat fruit.

Casper, the one three-toed sloth at Kids Saving The Rainforest, sleeping in bootcamp

Currently at Kids Saving the Rainforest, there are ten sloths: nine two-toed and one three-toed sloth. Five are in the nursery, where the baby animals are cared for. Three are permanent residents of the sanctuary. Two sloths, one of which is the three toed sloth, are in bootcamp, being prepared to go back into the wild and monitored until their release. There used to be four sloths in bootcamp and rehabilitation, but two two-toed sloths named Patty and Speedy were recently released. On Tuesday, when the interns and vet staff were changing out the sloth food in bootcamp, we saw that Patty was sleeping in a location that was easy to reach. Before any animal is released, the vet staff performs a physical exam to double check that they are in the best condition possible before release, and this was the perfect opportunity to catch her for her physical. Clemence, one of the vet techs, brought up a basket and falconry gloves and warned us that Patty was more of a fighter than her slow movements and easygoing appearance indicated. Sure enough, the moment they grabbed the back of her neck so that she couldn't bite us, she started hissing and swiping at everybody. To get her into the cage, we had to hold her head and grab all four of her limbs while pinning her claws to her paw. Sloths' claws aren't like a dog or a cat's claw; they're growths of the finger bone itself, so they are sharp and very strong. However, we were able to safely and gently contain the angry, hissing sloth to conduct her physical. We were very happy when she passed her physical with flying colors, and we were prepared to release her along with another sloth named Speedy that same day. However, a storm blew in that delayed their release until Friday.

Conducting Patty's physical exam in the veterinary clinic.

​On release day, most of the staff and all the interns hiked out to the back of Kids Saving The Rainforest's property with the sloths in baskets. We found a tree for each sloth that they would easily be able to climb that didn't have bullet ants or other dangers dwelling on it. Ellen, the new vet tech, was releasing Speedy, which would be the first animal she had personally released. She opened the top of the basket and raised it up to a branch. Slowly, a paw with two long claws reached out, grabbed the branch, and Speedy pulled himself up into freedom. Patty was released in a nearby tree by Dani, the head of our nursery who had raised Patty from the moment she was brought into the nursery as an orphan. It was a special moment for everyone, and I was very lucky to be there to watch it. This won't be the last time I see Speedy and Patty though, because both sloths were released with a tracking collar and will be followed for several weeks with telemetry equipment that was bought with a generous donation to KSTR. When following the sloths, we will observe the them and collect post-release behavioral data to double check that the methods we use to rehabilitate these animals are effective and that the animals are surviving and thriving upon release.

Speedy climbing up the tree he was released in.

After watching and working with sloths for about a week, I finally understand better why they are the way they are. Their most famous trait is their slowness and supposed laziness. Indeed, after observing sloths both in bootcamp and after release, I can confirm that they spend much of their time sleeping. When they do move, they move at an excruciatingly slow pace that is peaceful to watch but could possibly drive some people crazy. Biologically, what they've done is slow down their metabolism so that they have reduced calorie needs, rarely need to defecate, and spend most of their life moving slowly and sleeping. You wouldn't think  this is the best strategy in the unforgiving rainforest, but the jungle is so thick and tangled that they easily go unnoticed. Walking through bootcamp, there's been several times that I've walked right under a sloth curled up in a tree without even noticing it until someone pointed it out to me. If there was a sloth slowly climbing high up in a tree, any predator that was not actively looking for a sloth in that area would most likely miss it, which explains why they have survived for so long. I'm very glad that I've gotten the opportunity to learn about them, and I realize how important it is to look at animals in the context of their environment. For right now, I'll be continuing to track Speedy and Patty until we can confirm that they will be fine in the wild. I hope that you enjoyed learning about sloths as much as I have; thanks for reading!