Clues to the sloth’s sloth found in its genome

Researchers sequenced the genome of the pale-throated sloth, revealing genetic adaptations that contribute to its exceptionally slow metabolism and movement. Published online on June 18, 2026, in Nature, the study identified duplications in genes associated with mitochondrial function. Mitochondria are the powerhouses of cells, responsible for energy production, and alterations in these genes likely impact the sloth's energy expenditure. The findings suggest that the sloth's unique physiology is deeply rooted in its genetic makeup, allowing it to thrive on a low-energy diet and conserve resources. This genetic insight offers a molecular explanation for the evolutionary success of one of the slowest mammals on Earth. The research team analyzed the complete genome, identifying specific gene families that have undergone expansion or modification. These changes are hypothesized to optimize energy conversion and reduce metabolic rate, a crucial adaptation for an animal with limited caloric intake and a lifestyle that minimizes energy use. The study provides a foundation for further investigations into the physiological mechanisms underlying the sloth's extreme slowness and its ecological niche.