Life In The Slow Lane: The Sloths of Brookfield Zoo


If you’re in search of one of the sleepiest and slowest animals in the world, trek over to Tropic World - South America here at Brookfield Zoo. Keep your eyes peeled for a bundle of fur resting in a tree nook or curled up in an overhead basket catching some z’s. If you’re really lucky, you might even see these animals climbing on their rope bridges or having a healthy veggie snack. Who are we talking about? Sloths of course!

Brookfield Zoo is home to two different subspecies of sloth: Hoffman’s two-toed sloth (Choloepus hoffmanni) and Linnaeus’s two-toed sloth (Choloepus didactylus). There are two Hoffman’s two-toed sloths, Raisin and Lawrence, that can be found living on exhibit in Tropic World - South America. There is one Linnaeus’s two-toed sloth, Elsie, that lives at Wild Encounters behind the scenes but makes frequent appearances during zoo chats with the public as an Animal Ambassador.


Upon first glance, these two subspecies of sloths might look rather similar. Although they have many physical characteristics in common, they differ genetically. Studies have shown that an analysis of mitochondrial markers and chromosomes is one of the most effective ways to positively identify individual sloths to their correct subspecies (Steiner, Houck, & Ryder, 2011). In addition to the genetic identification techniques, there are also some differences between the species regarding hair length and color. Hoffman’s two-toed sloths have shorter hairs near their cheeks and throat that tend to be lighter in color.

Linnaeus’s two-toed sloths have longer hair around their face and neck that often matches the color of hairs found on their upper body as well. However, these hair color and length rules are not always accurate when determining a two-toed sloth’s exact subspecies. There is a high level of variation in coat color and length for individuals of different ages and geographic locations. In short, identifying two-toed sloths to a subspecies can be very tricky.

Regardless of any differences between the types of sloths found here at Brookfield Zoo, we can probably all agree that sloths have captured many of our hearts. These adorable animals appear to live a lifestyle that many of us would be jealous of; sleeping, eating, and hanging out all day. So what is a day in the life of a sloth really like?

All species of sloths are native to the tropical rainforest habitats of Central and South America. Sloths are arboreal animals, meaning they are well adapted to live almost their entire lives in the trees. They wake up in the trees, they move slowly around the trees, and then they fall back asleep in the trees (sleeping on average between 10-20 hours per day!). Their long limbs and claws allow sloths to grip branches comfortably as they move throughout the tree canopy. Sloths climb around with slow efficiency. An individual might only travel up to 40 yards in one day (World Wildlife Fund, 2019).

When moving about, sloths are often on the search for plants to eat and secure places to rest. Their slow metabolic rate allows then to conserve energy for long periods of time. Sloths don’t need to move quickly because their food source is stationary and their main defense from predators is their amazing camouflage in the trees. Their slow lifestyle isn’t actually laziness, it’s a survival method that allows them to fill a particular niche in the environment.

The life of a sloth may sound relaxing, but it has its unique moments as well! Sloths are surprising in several different ways. First, these animals move so slowly that algae grows on their fur and tints them a distinctly greenish color. Their coat of dense hair forms a controlled microclimate in the humid rainforest that allows the algae to flourish. In these cases, this makes them the only mammal to be considered even slightly “green” in color.

Secondly, although sloths are adapted to exist in the treetops, they are also strong swimmers! Sloths have been documented gently dropping out of trees into bodies of water, swimming (with speed), and moving from one section of habitat to another. This is an important skill if they want to find a mate as well.


Finally, sloths only defecate about once per week. Instead of going to the bathroom in the trees, sloths insist on climbing down onto the forest floor. This behavior is mysterious to researchers and a variety of theories have been put forth to explain why sloths do this. It seems like a risky choice to make as sloths are incredibly vulnerable to predators (like ocelots, jaguars, and pumas) on the ground. There is no definitive answer to this quirky behavior, but scientists theorize there could be some sort of symbiotic relationship between sloths, certain trees, and certain invertebrates found in the ground (Voirin, Kays, Wikelski, and Lowman, 2013).

Brookfield Zoo’s sloths can be found doing what sloths do best; sleeping, climbing, and eating their days away! Their home here involves access to multiple levels of habitat to climb within, a lot of nutritious vegetables and other plants, and an exhibit that is also home to a variety of other mammals and birds found in the sloth’s native Central and South American lands. Our sloths are cared for by a dedicated team of animal care specialists who check on their health, maintain trusting relationships with them, devote each and every day to studying their lifestyle, and are constantly working to develop innovative methods of care to give them the highest quality of life.

Feel free to stop by any day of the year, channel some sloth energy, and take a walk on the slow side.

 - Written by Mallory Fischer, Interpretive Programs Coordinator, Chicago Zoological Soceity

Works Cited

Steiner, C. C., Houck, M. L., and Ryder, O. A. (2011). Species identification and chromosome variation of captive two-toed sloths. Zoo Biology, 30(6): 623-635.

Voirin, B., Kays, R., Wikelski, M., and Lowman, M. (2013). Why do sloths poop on the ground? Treetops at Risk: Challenges of Global Canopy Ecology and Conservation, 195-199.

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Posted: 12/20/2019 2:06:22 PM by Sean Keeley

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Since the opening of Brookfield Zoo in 1934, the Chicago Zoological Society has had an international reputation for taking a cutting-edge role in animal care and conservation of the natural world. Learn more about the animals, people, and research that make up CZS here at our blog.


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