No menu items!

COSTA RICA'S LEADING ENGLISH LANGUAGE NEWSPAPER

HomeTopicsEnvironment and WildlifeFrom Dinosaurs to Treetops: The Extraordinary Evolution of Sloths

From Dinosaurs to Treetops: The Extraordinary Evolution of Sloths

Did you know that sloths used to be one of the most biodiverse groups of mammals to ever live in South America before the formation of the isthmus? Yeah, maybe it’s not my best pickup line, but an excellent topic of conversation, nonetheless.

Sloths are some of the coolest and cutest creatures to exist in the 21st century, but their story really started 65 million years ago. Sloths are Xenarthrans, a group of animals that includes the armored armadillos and the fierce anteaters. Their evolution starts long before most any other mammal.

Xenarthrans as we now know them started to evolve at a time when non-avian dinosaurs still roamed the Earth! Cool, right? This group was particularly adept at what they did due to various specializations relating to digging, such as specialized joints. They also had extra points of attachment between the vertebrae in the back. Because of this they were able to branch out into the variety of forms we see today.

Armadillo in Costa Rica
Photo via Toucan Rescue Ranch.
Costa Rica Anteater
Photo via Toucan Rescue Ranch.

Sloths as we know them appeared on Earth roughly 46 to 33 million years ago, in what is known as the Oligocene epoch. The last common ancestor between two- and three-fingered sloths diverged almost 40 million years ago, making two-fingered and three-fingered sloths as related to each other as house cats and hyenas!

Two-fingered sloths and three-fingered sloths are as closely related to each other as cats and hyenas.
Photo by Charles J Sharp, via Creative Commons.

Sloths quickly diversified into lots of different forms, from the gigantic 6-meter tall Megatherium, to the marine sloths like Thalassocnus and even some of the weirder species like the digging Lestodon, the rock climbing Diabolotherium and the armored Glossotherium.

Sloths used to be everywhere – from mountain cliffs to oceans!

Marine sloth
Photo by Michael B. H. / Creative Commons.

Nowadays, however, sloth diversity has been highly reduced. After the Americas collided with each other and the Great American Biotic interchange occurred, there wasn’t a lot of space for the mighty sloth. Experts believe that overhunting by early humans may have lead to the decline of this mighty creature, and the reduced families that we have now are also facing this problem.

Today, we only have six different species of sloths, four of them three-fingered sloths and two of them two-fingered sloths. All living sloths are arboreal creatures and all of them are facing problems due to poaching and human interaction.

Twix the sloth in Costa Rica
Via Toucan Rescue Ranch.

That is why it is important that we have rescue centers like the Toucan Rescue Ranch! Its mission is to ensure that one of the most wonderful and, once mightiest, groups of mammals to ever exist doesn’t go extinct.

— Andrés Sáenz Bräutigam is a Veterinary Assistant & Tour Guide at Toucan Rescue Ranch. 

This article was produced by The Toucan Rescue Ranch. The Toucan Rescue Ranch specializes in helping wild animals recover so that they can be reintroduced into the wild.

Trending Now

Costa Rica’s Piangua Mollusk Threatened by Pineapple Farm Runoff

Costa Rica’s Térraba-Sierpe National Wetland, a 33,000-hectare haven of mangroves and rivers, is under siege from an unlikely source: pineapple farms. A study by...

A Costa Rica Love Story: From Rustic Cabina to Separate Dreams

My Tica wife and I have been together for over a quarter century. When we met, I was living a simple life here. Three...

Costa Rica Hunts for Nicaraguan Hit Squad After Exile’s Assassination

Costa Rica’s Judicial Investigation Agency (OIJ) is investigating whether a hit squad tied to Nicaragua’s Ortega-Murillo regime is targeting exiled critics on its soil....

Celso Gamboa Allegedly Ran Drug Ring with Costa Rican Government Ties

Celso Gamboa, once Costa Rica’s Security Minister and a Supreme Court judge, now faces extradition to the U.S. for leading a major cocaine trafficking...

2025 Gold Cup: Honduras Advances After Dramatic Shootout, Mexico Ends Goal Drought

Honduras, with a surprising and dramatic penalty shootout victory over Panama, and Mexico, with a lackluster win against Saudi Arabia, advanced Saturday to the...

Costa Rica’s Cutris Mining Bill Threatens Massive Environmental Damage

Costa Rica’s government is pushing a controversial bill that could open the entire Cutris district in San Carlos—848 square kilometers—to open-pit gold mining. The...
spot_img
Costa Rica Tours
Costa Rica Coffee Maker Chorreador
Costa Rica Coffee Maker Chorreador
Costa Rica Travel Insurance
Costa Rica Rocking Chait
Costa Rica Travel

Latest News from Costa Rica