Energy and water requirements of lactation in the North American porcupine, Erethizon dorsatum.
1. Energy and water requirements of lactating porcupines were compared with results of previous studies on energetics of reproduction in small-bodied rodents. 2. Mass-specific food and water intake of control and lactating porcupines was examined throughout the 68-78 days of lactation. Water intake of lactating females was 16% higher than that of non-lactating animals. 3. Digestive efficiency of porcupines fed commercial rabbit chow was 54-60%; there was no significant difference in efficiency between lactating and non-lactating animals. 4. Total mean energetic intake throughout lactation was only 17% greater than that of non-lactating animals. 5. Reproductive rate and costs of lactation in porcupines are considerably less than in other rodents and other comparably-sized mammals, but the amount of energy allocated to each offspring is quite high. 6. The reproductive pattern of porcupines is associated with low juvenile mortality and long adult lifespan (both of which reflect the porcupine's protective morphology), and may be related to the quality of winter diets.