Sloths show remarkable breath‑holding ability thanks to a slow metabolism and physiological adaptations that let them remain submerged far longer than many marine mammals
Recorded breath‑holding capacities
Sloths have been observed to slow their heart rate and remain submerged for extended periods, with reported breath‑holding times of up to about 40 minutes in some cases.
Comparison with dolphins
By contrast, dolphins—adapted for active swimming and regular deep dives—typically hold their breath for far shorter periods on routine dives, commonly around several minutes and often in the range of about 5–10 minutes depending on species and activity.
Physiological explanations
Sloths’ slow metabolic rate reduces oxygen demand, allowing their bodies to conserve oxygen while submerged; they can also reduce heart rate to minimise oxygen consumption during dives. Dolphins instead rely on efficient oxygen storage in blood and muscle and rapid gas exchange at the surface to support active swimming, which favours shorter, more frequent breaths rather than very long apnoeas.
Ecological significance
For sloths, extended submergence is an adaptive behaviour that helps them evade predators and cross waterways with minimal energy expenditure; for dolphins, shorter but more controlled dives suit pursuits of active prey and long‑distance travel, illustrating different evolutionary solutions to life in and around water.
Takeaway
Although it may seem surprising, sloths can outlast dolphins in single breath‑hold duration due to their low metabolic demands and physiological adjustments, while dolphins use different respiratory strategies optimized for an active marine lifestyle.