About This Project

It’s well established: tree sloths are weird. So we can assume that extinct ground sloths were weird too. Studying sloths is tough because it’s hard/impossible to observe their behaviors, yet knowing their (paleo)ecology is important for conservation and interpreting paleoecosystems. Our project will use stable isotopes as a proxy for diet/habitat thus eschewing direct observation. This serves two goals: a better grasp of sloth ecology and a metric for applying these techniques to fossil sloths.

Ask the Scientists

What is the context of this research?

I was inspired to do this project because the more I learn about sloths the more I realize just how little we know about them. The work I did for my Masters looked at the microscopic surface texture of modern and fossil sloth teeth to tell what they were eating, and for my Ph.D. I wanted to take those sorts of proxies to the next level. Stable isotope analysis is a really great tool for that. The technique relies on the old adage, “you are what you eat” but in this case we’re talking about the actual atoms in your food and water that turn into the tissues of your body. By analyzing those tissues, we can get a sense of what you were eating and drinking when those tissues were forming, which is super helpful when you can’t observe the animal because they’re extinct or up a really high tree.

What is the significance of this project?

The reason I really wanted to develop this project is simple: it’s work that needs to be done but hasn’t yet. As a paleontologist, I was aware of a handful of studies that looked at the stable isotope geochemistry of fossil sloths. These results were typically interpreted as any other large herbivore (remember: ground sloths were huge) even though the tissue being sampled was different and sloths weren’t closely related to the herbivores they were being compared to. I see this as a problem. Sloths are weird. Weird enough that I was skeptical of any untested assumptions about their ecology, so that’s why I’m proposing this project, which will test modern sloths to learn a lot we don’t know about their ecology and see if they’re better a comparison for interpreting their fossil relatives.

What are the goals of the project?

There are two main goals for this project. The first is to use stable isotope analysis to greatly increase our knowledge of modern sloth ecology. The second is to use those insights to rethink how we view similar data from fossil sloths. These results will form a chapter of my Ph.D. dissertation and will also be presented at conferences, published in peer-reviewed journals, and talked about on my podcast. Last year I collected the samples I’d need from deceased frozen sloths at the Sloth Sanctuary in Costa Rica, but I left the samples there while I waited for the proper permits to export them to the US, which we got a few months ago. With funding, I’ll head down to pick them up. Once back, I’ll get the samples prepared and analyzed over the summer with plans to begin writing in the fall.