Final answer:
Chimps, gorillas, and women in foraging societies typically nurse their infants for 1-2 years (option B). This extended nursing period is due to the helpless nature of infants at birth and their long adolescence. Cultural practices and environmental adaptations result in variability in weaning age across different societies and species.
Step-by-step explanation:
The duration that chimps, gorillas, and women in foraging societies nurse their infants is best answered by option B, which suggests a time frame of 1-2 years. This period aligns with the observation that female great apes and foraging human mothers provide substantial care to their offspring during their early years, a necessity due to the infants being born helpless and their long maturation time.
While La Leche League International reports a worldwide average weaning age of four to five years, in some foraging societies this period may extend for several years as part of their cultural practices. In contrast, a study of U.S. mothers showed that the mean weaning age was nine months, indicating significant variation in nursing duration across different cultures and species. In terms of primates, their social structures and parenting behaviors are complex and adapted to their environments, necessitating a flexible and extended period of nursing that supports the development of offspring.
The gestation period for great apes lasts 8-9 months, and young are heavily reliant on their mothers for survival and learning throughout their early years. This prolonged adolescence is clearly seen in species such as chimpanzees and gorillas, and is similarly mirrored among human foraging societies, albeit with cultural differences influencing the length and nature of the nursing period.