Summary
A study was made of respiration and metabolism in Amazonian manatees (Trichechus inunguis) weighing between 20 and 170 kg. Thse animals had a low metabolic rate, 0.36 times that predicted by Kleiber's (1975) equation for placental mammals. They also had a low breathing frequency and minute ventilation, and high O2 extraction and CO2 output. The mean dive times were less than 2 minutes but dives of up to 10 min. duration were noted. Sequential dive times exhibited a pattern only in that several short dives followed a prolonged dive.