Intraday Feeding Patterns in Infant Rhesus Monkeys and the Effects of Missing a Meal

During the first month of life, infant rhesus monkeys (N = 96) were fed 7 times a day for the first 21 days and were fed 6 times a day thereafter. Fifty monkeys were fed SMA, a formula designed for human infants (9% protein, 43% carbohydrate, and 48% fat); 46 were fed one of three laboratory-confected diets varying in the amount of protein and carbohydrates provided. Although the diets had differential effects on weight gain, overall daily consumption was practically unaffected. A characteristic pattern was evident soon after birth: The first meal of the day (8:00 am) was one of the largest, and the following two meals were usually the smallest; the next peak spanned the 4:00 pm and 8:00 pm feedings. The meal following a missed meal was slightly larger than normal. To some extent, the large meal at 8:00 am can be attributed to the 10-hr absence of food during the night, but the peak at 4:00 pm and 8:00 pm cannot be so accounted for. The adult bicuspid pattern of eating hence appears to develop very early in life.