Cover Image: May 2009 Scientific American Magazine See Inside

On a Mission to Save Sloths

A living Muppet among the tropical treetops















Share on Tumblr



Image: MATT COLLINS

  • What a Plant Knows

    How does a Venus flytrap know when to snap shut? Can it actually feel an insect’s tiny, spindly legs? And how do cherry blossoms know when to bloom? Can they...

    Read More »

Life is going to present special challenges to any creature named for a deadly sin. Sloths really deserved better. They could have been called deliberates or contemplatives. How sloths conceive of themselves remains a secret—three-toed sloths (Bradypus variegatus) seem to smile a lot, but they’re not talking.

They didn’t say anything to me, anyway, at the Aviarios Sloth Rescue Center just north of Cahuita, along the Caribbean coast of Costa Rica, which I visited on March 6. How I got to Aviarios is a story of hardship and struggle. Not on my part, of course. I’m talking about the incredibly diligent and attentive staff on the luxury cruise ship Zuiderdam, which left Fort Lauderdale on February 27 for the Bahamas, Aruba, Curaçao, Panama and Costa Rica before returning to Florida. The biggest test of my mettle was seeing whether I could finish yet another extravagant dinner. If the creatures slowly digesting leaves in the trees of the Aviarios sanctuary are sloths, call me glutton. (Which, coincidentally, is the opening line of my planned novella Mopey Doc, about a melancholy physician with a body mass index of 37.)

The trip was the third in a continuing series of Scientific American cruises put together by InSight Cruises, in which a sterling faculty of expert scientists and the occasional freeloading journalist lecture to an enthusiastic and well-adapted audience. On this creative and intelligently designed voyage, the theme was evolution.

Along the way, the ship was lifted 85 feet in the legendary Gatun Locks, the Atlantic-side steps of the Panama Canal, into the vast Gatun Lake. Four cruise lecturers then took a small motorboat across the lake’s choppy surface to tour Barro Colorado Island, home to the Smithsonian Tropical Research Institute. A century ago, before the flooding of the island’s valley as part of the canal’s construction, Barro Colorado was a hilltop. Now it’s a giant island laboratory (that’s also home to sloths). A historic three-decades-old research effort includes tagging and periodically evaluating every single plant—a quarter of a million currently—on part of the island to try to get a picture of how tropical biodiversity is established and maintained. All that foliage provides ample cover for countless ticks, some of which temporarily enjoyed my patronage while masquerading as freckles.

The day after going through the Gatun Locks, I was face to incredibly cute face with Buttercup, the original rescued sloth at the Aviarios center. Husband-and-wife team Luis Arroyo and Judy Avey-Arroyo were bed and breakfast proprietors in 1992 when three neighborhood children brought them Buttercup, then an orphaned infant. The Arroyos nursed the three-fingered sloth to a healthy adulthood and became known as sloth savants. When local people found hurt or orphaned sloths, they brought them to Luis and Judy. By 1997 the Arroyos were in the sloth-saving business full-time.

The challenges are constant, as the scientific literature on sloths is sparse. The Arroyos are attempting basic studies, for example, on the makeup of sloth milk. Babies being fed by their mother “gain weight sometimes three or four times faster than the orphans we’re hand-raising,” Judy says. “So mother’s milk has something—maybe a high fat content. Our milk study has failed so far because we can’t take enough milk from the mother to analyze.” And that’s because mothers don’t bother to store milk, as the baby is always right there, hanging on. In business jargon, sloth milk production is a just-in-time inventory strategy—foxes may have the rep, but it’s sloths that are sly.

Despite their name, sloths are actually real go-getters, sleeping only about 10 hours a day as compared with the 24, minus meal breaks, of your average house cat. Their Muppety, monkeylike appearance belies their true taxonomical standing, more closely related to anteaters and even armadillos. And a sloth does indeed spend most of its time in the canopy, coming down to ground level about once a week to urinate and defecate. Its lifestyle is thus eerily similar to a rare variety of primate, the New York City penthouse-dwelling supermodel.



4 Comments

Add Comment
View
  1. 1. radapetric 02:57 PM 11/19/09

    Do sloths produce ultrasound and if so is there a scientific article to support that.

    Reply | Report Abuse | Link to this
  2. 2. radapetric 03:00 PM 11/19/09

    Do sloths produce ultrasound? and if so is there a scientific article that supports it?

    Reply | Report Abuse | Link to this
  3. 3. PacificLots 07:25 AM 12/10/09

    As a property owner in Costa Rica, sloths are a regualar occurance in my life. I recently wrote a story about them in our blog which you can find on our website at www.pacificlots.com/Costa-Rica-Blog/

    Reply | Report Abuse | Link to this
  4. 4. Alllies 01:19 PM 9/30/12

    They are now up to 140 sloths, keep them caged up 24hours and feed them dog food. I can't believe you are not reporting on the abuse that is occuring everyday at this place. They charge volunteers to work there and provide the minimal care to these animals. They are also BREEDING them and keeping them captive. This has become a money generating business for Judy Avey-Arroyo and her family and it's not about saving these animals. This lady is sick and has some serious mental issues. She also houses other wild animals that are perfectly healthy in her home. She is a animal hoarder with a serious problem and articles like this are not telling the true story. STOP GIVING YOUR MONEY TO THIS PLACE.

    Reply | Report Abuse | Link to this
Leave this field empty

Add a Comment

You must sign in or register as a ScientificAmerican.com member to submit a comment.
Click one of the buttons below to register using an existing Social Account.

More from Scientific American

See what we're tweeting about

Scientific American Editors

More »

Free Newsletters


Get the best from Scientific American in your inbox

Solve Innovation Challenges

Powered By: Innocentive

  SA Digital
  SA Digital

Science Jobs of the Week

Email this Article

On a Mission to Save Sloths: Scientific American Magazine

X
Scientific American Magazine

Subscribe Today

Save 66% off the cover price and get a free gift!

Learn More >>

X

Please Log In

Forgot: Password

X

Account Linking

Welcome, . Do you have an existing ScientificAmerican.com account?

Yes, please link my existing account with for quick, secure access.



Forgot Password?

No, I would like to create a new account with my profile information.

Create Account
X

Report Abuse

Are you sure?

X

Institutional Access

It has been identified that the institution you are trying to access this article from has institutional site license access to Scientific American on nature.com. To access this article in its entirety through site license access, click below.

Site license access
X

Error

X

Share this Article

X