OPTIMAL LITTER SIZE - DOES IT COST MORE TO RAISE A LARGE LITTER IN CALUROMYS-PHILANDER

Food intake of lactating Caluromys philander, a didelphid marsupial, was recorded from parturition until weaning of the pouch young. Variation in the average caloric value of daily food intake throughout lactation, in relation to litter size, showed no significant differences, but females increased food intake during late lactation, prior to weaning. Food intake was positively correlated with total litter mass at weaning. Moreover, there were significant differences in body mass and body length of offspring at first pouch exit (3 months) and at weaning (4 months): young born in small litters (1-3) were bigger than those born in large litters (6-7). Reproductive success is discussed on the assumption that pouch-young survival depends on food resources.