Why do sloths move so slowly?

Sloths are slow primarily as an adaptation to their low-calorie, nutrient-poor diet of leaves. To survive on this limited energy intake, they maintain a metabolic rate that is only 40–45 percent of what is expected for mammals of their size. Their slow-moving, arboreal lifestyle is specifically designed to conserve energy.12

Additionally, their slowness serves as a survival strategy. Many predators, such as jaguars, are visual hunters that rely on detecting movement; by moving slowly, sloths are less likely to attract attention. Their camouflage is further enhanced by algae that grows on their fur, allowing them to blend into the forest canopy.2

Physiologically, sloths are heterothermic, meaning they have imperfect control over their body temperature. When their body temperature drops, they can become torpid, which further necessitates a slow pace. Ultimately, sloths have evolved to be slow because it is an efficient and effective way for them to exist in their environment.23