The waning of dependence in infant free‐ranging yellow baboons (Papio cynocephalus) of Mikumi National Park

Abstract

Development toward independence during the early years of baboon life is reflected in the infant's transition from riding on its mother to walking on its own during progressions from one location to another. This transition was studied during the first year of life in 55 infants from two differently sized troops living in Mikumi National Park, Tanzania. There was a nearly linear transition in the first year from almost 100% ventral riding to almost 100%walking. The amount of dorsal riding started near zero, reached a plateau lasting from about the 15th to the 26th wk of life, and then gradually declined to zero. Dorsal riding did not replace ventral; rather, dorsal riding increased in frequency until it occurred about as often as ventral riding. Prolonged ventral riding by infants of the smaller of the two troops may have been due to spacing differences or to greater nervousness among members of the smaller troop. There were no significant differences in riding or walking associated with the time of day or the infant's sex. The rate of transition from riding to walking was greatest from about the fifth to the seventh months, which may be especially significant time in the early development of independence.

Lifetime reproductive success, longevity, and reproductive life history of female yellow baboons (Papio cynocephalus)of Mikumi National Park, Tanzania

“…All 72 females were dead as of 9 May 1996. The birth and death dates of their 302 observed offspring were either known to the day or could be determined usually to within two or three days and never more than a month [Rhine et al, 1984]. On 10 April 1999, all offspring of the subjects were either dead or had reached the age of at least six years.…”

Insect and meat eating among infant and adult baboons (Papio cynocephalus) of Mikumi National Park, Tanzania

“…Adults were observed over a period of 37 months, including a period of 25 months during which infants were also studied. The censusing procedures by which an infant's age was determined were described previously (Rhine et al, 1984).…”

Costs of maternal care: infant-carrying in baboons

“…At birth, a neonate is carried continuously as it clings to its mother's ventrum, grasping with hands and feet to the fur on her sides. After a few months, the infant generally shifts to sitting or lying on its mother's back (DeVore 1963;Ransom and Rowell 1972;Rasmussen 1979;Altmann et al 1981 ;Rhine et al 1984). Infant-carrying by individuals other than the mother is rare and usually of brief duration.…”

“…Most maternal care declines after the infant is several months old (DeVore 1963;Ransom and Rowell 1972;Nash 1978;Altmann 1980;Nicolson 1982Nicolson , 1987Rhine et al 1984Rhine et al , 1985. Although some amount of suckling, thermoregulatory and predator protection, and social support continues beyond the first year of life, mothers in two groups of Amboseli baboons usually resume sexual cycling by the time their infants are 8-14 months of age, and conception occurs a few months later.…”