Source news.wisc.edu

Sloths are my favorite arboreal folivore, which is just the short, scientific way of saying an animal that lives in trees and feeds only on leaves. Observing this placid-looking creature was and still is quite a novelty for visitors (and locals, like me) to Costa Rica given that its sluggish nature is uncommon for a arboreal vertebrate…and its adorable fuzziness is simply too cute not to stare at. To understand the rarity of this type of animal (arboreal folivores) better, a group of researchers from the University of Wisconsin traveled to Costa Rica and began to investigate the sloth’s adaptation to a slow lifestyle.

One of the reasons sloths move so slowly is because their leaf-based diet has low nutritional value, therefore they do their best (or should I say, do very little) to expend as little energy as possible. Researchers discovered that sloths “expend as little as 110 calories of energy a day, roughly the same amount of calories found in a baked potato. It is the lowest measured energetic output for any mammal.” Fascinating!

In addition, some biological adaptations are that their body has a reduced metabolic rate and a remarkable regulation of body temperature, all contributing to their slowness. As one of the researchers, Jonathan Pauli, notes, “the findings reinforce the concept that arboreal folivores are tightly constrained by nutritional energetics. The more specialized the tree-dwelling animal, the lower the daily energy expenditure.”

Read the full article here.