Sloths are tree-dwelling mammals recognized for their slow movements, a pace that extends to nearly every aspect of their lives. This deliberate approach also influences their internal processes, including digestion and elimination. The infrequent nature of their defecation, combined with the unique ritual surrounding it, presents an intriguing biological phenomenon.
The Infrequent Pooping Schedule
Sloths defecate only once per week, ranging from every five to seven days. This infrequent schedule results in a substantial accumulation of waste. During a single defecation event, a sloth can expel an amount of faeces equivalent to one-fifth to one-third of its body weight. This volume is often released as a single, large mass or several cherry tomato-sized “nuggets.” The faecal matter is dark and fibrous, reflecting their leaf-based diet.
While two-toed sloths sometimes defecate directly from the canopy, three-toed sloths are more particular, consistently descending to the forest floor, often at the base of the same tree.
Biological Reasons for Slow Elimination
The reason for a sloth’s infrequent bowel movements lies in its slow metabolism, among the lowest observed in any mammal. Their diet consists mainly of leaves, a food source low in calories and difficult to digest due to its high cellulose content. This necessitates a prolonged digestive process, with a single meal taking 11 to 30 days to pass through, averaging around 16 days.
Sloths possess multi-chambered stomachs that function as fermentation tanks, housing specialized bacteria to break down the tough plant material. This slow digestion allows them to extract the maximum possible nutrients from their limited diet. Consequently, their bodies accumulate waste products at a gradual rate. Conserving energy is important for sloths, and frequent defecation would expend resources. Each trip to the ground for elimination can consume approximately 8% of a sloth’s daily energy budget.
The Risky Trip to the Forest Floor
For three-toed sloths, defecation involves a slow descent from the tree canopy to the forest floor. This journey exposes them to predators such as jaguars, ocelots, harpy eagles, pumas, and other ground carnivores. Studies indicate that more than half of all adult sloth deaths occur during these vulnerable moments on the ground.
Once on the forest floor, the sloth performs a distinctive “poop dance,” wiggling its hindquarters to dig a small hole for its faeces. Three-toed sloths use their tails for digging, while two-toed sloths may use their entire pelvic area. After defecating, they may cover the waste with leaf litter.
Several theories attempt to explain why sloths undertake this risky behavior. One theory suggests it aids in nutrient cycling, as their nitrogen-rich waste fertilizes the trees they inhabit. Another posits that it serves as a form of communication, with pheromones in the faeces providing information about territory or reproductive status, particularly for females in estrus.
A theory suggests a symbiotic relationship with moths and algae that live in the sloth’s fur. When the sloth descends, female moths lay their eggs in the dung, and the larvae feed on it. Adult moths then return to the sloth’s fur, bringing nutrients like nitrogen, which fertilize the algae growing on the sloth’s coat. Sloths are believed to consume this algae, which is rich in lipids, to supplement their low-nutrient leafy diet. This complex interaction may provide a nutritional benefit that outweighs the dangers of the ground descent.