A few months ago we introduced you to Sam Trull, a zoologist in Costa Rica who had taken on an incredibly difficult job: teaching orphaned baby sloths how to be wild. We delved into both sloth science and Trull's deeply committed, intimate care of these unique creatures that, from a scientific perspective, remain largely mysterious. We also created a Facebook-exclusive video featuring photos from Trull's excellent photography book, Slothlove, which documents her work with (and, clearly, love of) sloths. In short, we couldn't get enough of these sloths—and judging from the huge response to our coverage, neither could you.

Which is why we're now sharing some sad news: Monster, one of Trull's sloth stars, was recently attacked and killed by an ocelot.

Monster, a three-toed sloth, was just two weeks old when she came into Trull's care after having been rescued from the middle of a road. I met Monster—and Trull—in Costa Rica two years ago at Kids Saving the Rainforest, a rescue and rehab center for wildlife near Manuel Antonio, on the Pacific coast.

"Met" is the wrong term though; in her efforts to keep the sloths as wild as possible, Trull kept almost all the sloths out of sight and completely forbade any interaction between them and visitors (and most staff) of the wildlife rescue center. I lucked out during my visit, because Trull had taken Monster into a windowed lab with her while she tended to Tommy, a newborn baby howler monkey she wore strapped to her chest for hours on end. Our primate relatives need constant contact when they're young as much as our human newborns do, so Trull wore Tommy all day, every day.

In the video below, you can see baby Monster sitting in a basket serenely nibbling on hibiscus flowers while Trull feeds Tommy through a syringe. Trull is also a trained primatologist who spent years working with lemurs, so simultaneously tending to both Tommy and Monster—very different animals with very different needs—wasn't as strange as it may seem at first glance. It was impressive though.

Shortly after I shot this video, Trull and I sat down for a lengthy and fascinating interview. (She didn't wear Tommy to the interview; despite acting as his monkey mom, she was trying to keep him wild too, so my presence would have been problematic.) Her ambitious sloth rescue-rehab-release program—the main initiative of her newly launched nonprofit, The Sloth Institute Costa Rica—was in the late planning stages and hadn't really gotten off the ground yet. So there wasn't much to report on.

Yet for the next two years, her work stuck with me; it seemed like research that would push the envelope on both wild animal release and sloth science. People had attempted to release rescued sloths back into the wild before. It was largely a death sentence.

During that time, I checked in periodically with Trull to see how the project was progressing. She had created a sloth "boot camp": an enclosed, protected patch of forest where the animals could learn how to forage, among other essential skills, before being released back into the wild to fend for themselves. When I learned earlier this year that the first sloths to "complete" the boot camp were going to be released into the rainforest, I knew it was finally time to go full sloth for mental_floss readers.

The first sloths to be released were Kermit and Ellie. Monster, now 2.5 years old, followed suit soon after. Before Monster was released, Trull told me that she was both nervous and excited that her "slothy soulmate" would be living wild for the first time since she was just two weeks old. “Releasing her will be very emotional," she said. "But it’s also very amazing and reassuring to see their instincts kick in with certain things. At least they’re coming at this with some knowledge, and I don’t have to teach them everything. But to see them learn everything I’ve taught them is very rewarding as well.”

Monster survived for months on her own before the ocelot attacked her. Her death is a sad outcome, but it's also not especially surprising. Ocelots are a main predator of sloths, and sloths have few defenses. Their legendary slowness generally helps them avoid detection. But once spotted by a creature redder in tooth and claw than they are, there's little they can do to protect themselves.

So why are we telling you this story? Partially because I kind of fell in love with Monster when I saw her in that basket in Costa Rica two years ago. But primarily, because science is often portrayed inaccurately: as a flawless "last word" on a subject, a cold-hearted endeavor, or both. But science is neither absolute nor heartless. It's a method of investigating the natural phenomena of the world used by people who are, in my experience as a science journalist, largely driven by sincere curiosity and passion. It's a work in progress. It doesn't always go as planned. There's a lot of trial and error. Monster's death is a prime example of this basic truth: All the research, preparation, and good intent undertaken by a committed scientist couldn't save this one sloth from a predator who eats her kind. That's just the way it works in the rainforest.

But while Monster may be gone, what Trull learned about sloths by training, studying, releasing, and—yes—loving that three-toed, algae-covered, moth-hosting, hibiscus-eating, infrequently pooping animal will likely inform sloth science for years to come. And in a bit of good news, the other sloths Trull has released are doing well in the wild.

RIP, Monster.

If you'd like to support this science, The Sloth Institute of Costa Rica has created the Monster Memorial Fund; donations will support the construction of a Wild Sloth Health (WiSH) lab, where "research efforts will focus on monitoring different health parameters to get an overall picture of the quality of life of populations of sloths." They'll name the lab after Monster. You can also keep up with the Sloth Institute’s work through Trull’s Tumblr and Twitter feeds.