How Often Do Sloths Poop? The Weekly Trip to the Ground

Why do sloths poop so rarely?

Sloths poop rarely because everything in their body runs slowly. They eat leaves, which are low in energy and hard to digest, and they break them down slowly with the help of bacteria in a large, many-chambered stomach. Food can take days to weeks to pass from one end of a sloth to the other.

Because so little food passes through each day, droppings build up gradually in the lower gut, and the sloth can hold them for a long time. When it finally goes, the amount is impressive. Often-quoted estimates suggest a sloth can lose up to about a third of its body weight in droppings and urine in one visit, although the true figure varies a lot between individuals.

The weekly trip to the ground

For a three-toed sloth, the bathroom routine follows a set pattern:

1. The descent. The sloth climbs slowly down the trunk of its tree, often the same tree where it feeds.
2. Digging. At the base it makes a shallow hollow in the leaf litter or soil, using its short tail and hips.
3. Relieving itself. It defecates and urinates, a process that can take several minutes.
4. Covering up. It scrapes some leaves or soil over the pile.
5. The climb. It heads back up into the canopy, where it is safe again.

Because sloths climb so slowly, the whole trip down and back up takes a long time, and the sloth is exposed for all of it. Videos of sloths shifting their hips as they dig have made the “poop dance” famous online.

Why risk coming down? The main ideas

Coming down is costly. A sloth on the forest floor is slow and exposed to jaguars, ocelots and other predators, and climbing down and back up burns energy that a sloth can hardly spare. Yet three-toed sloths keep doing it. Scientists have suggested several reasons:

• Hiding from predators. Dropping dung from the canopy might draw attention to the tree, so burying it at the base could keep the sloth hidden.
• Communication. Dung piles at the base of trees may carry scent messages, for example helping males and females find each other.
• Feeding their trees. Dung left at the foot of a favorite tree returns nutrients to that tree. Most experts think the benefit is too small to explain the behavior.
• An old habit. Some researchers argue that sloths simply inherited the behavior from ancestors that lived on the ground, and that predation during these trips is rare enough that there has been no strong pressure to change it.

The sloth moth hypothesis

One of the most surprising ideas involves the moths that live in sloth fur. Several species of small moths, such as Cryptoses choloepi, spend their adult lives in the coat of three-toed sloths. When the sloth comes down to defecate, female moths leave the fur and lay their eggs in the fresh dung. The caterpillars feed in the dung pile, and the new adult moths fly up into the canopy to find a sloth of their own.

A 2014 study led by Jonathan Pauli in Costa Rica suggested this could be part of a three-way partnership. Sloths carrying more moths had more nitrogen in their fur and more algae growing there. The algae are eaten by sloths and may give them extra nutrients. If this is right, the trip to the ground helps keep the moths, which in turn help feed the sloth’s algae “garden”. Other scientists are not convinced, and the question remains open. Learn more about this fur ecosystem in why do sloths have green fur?

Two-toed sloths do it differently

Two-toed sloths, such as Hoffmann’s two-toed sloth, also come down to defecate every few days, but their habits are less fixed. They are more mobile on the ground, come down more often for other reasons such as changing trees, and do not always use the same tree. Their fur carries far fewer moths.

Their diet also differs. Two-toed sloths eat more fruit and travel more widely, which may make an occasional trip to the ground less of a burden for them than for the slower, leaf-only three-toed sloths.

A risky moment, but a rare one

Predators do sometimes catch sloths on or near the ground, and near towns domestic dogs are a growing danger. How often this happens is still debated: some researchers describe the trip as a major cause of sloth deaths, while others point out that few attacks during defecation have actually been recorded.

If you visit a forest in Central or South America and see a sloth near the ground, give it space and keep dogs away. It is probably just making its weekly trip and will soon head back to the safety of the treetops. Disturbing it may make it abandon the effort or stay exposed for longer.