Proximity between the infant and its mother and the development of independence in rhesus monkeys (Macaca mulatta).

A randomly selected group of rhesus monkeys (Macaca mulatta) living in seminatural conditions has been utilized to study the relationships between an infant and its mother and between an infant and the other members of the group during the development of the infant from the 1st to the 6th month of life. Considering the proximity (0 to 3 m) for different types of partners, it has been found that the greatest difference between sexes occurred towards the 3rd month of the infant's life. For the behaviour On mother (proximity 0 m) the author has made an extra analysis. The results show that, in respect of the development of the infants, the relative frequency and duration of On mother decrease for both male and female infants, though at different rates: from the 3rd month of life, the female infants stay longer in On mother than the male infants. A significant positive correlation between frequency and duration of On mother was found in females.