Abstract 1. 1. Oxygen consumption was determined after intense work periods varying from 10 sec to 270 sec. 2. 2. Exhaustion occurred in 2 min. 3. 3. Lactate was produced during the first 10 sec at a rate severalfold that of the last 10 sec of the 2 min work period. 4. 4. Although the rate of anaerobic glycolysis in the alligator resembled that of the smaller anolis lizard, the rate of repayment of the resulting oxygen debt was inversely proportional to the metabolic rate, requiring 300 min for the 500 g alligator compared to 90 min for the 5 g lizard.