Communities of baboon troops (Papio cynocephalus) in Mikumi National Park, Tanzania. A preliminary report.

Daily censuses were collected on a troop of 108-130 yellow baboons (Papio cynocephalus) for 22 months. 12 adult females, 5 subadult males, and 26 adult males either emigrated from or immigrated into the troop. 10 adult females immigrated into the troop over a 4-month period. 2 adult females emigrated from the troop. 1 of the latter probably conceived while absent. This female returned to the troop when pregnant and subsequently bore and successfully raised the offspring. There was a strong negative correlation between the relative size of the subadult males (a correlate of age) and the date on which they emigrated. Only 6 old and past-prime males never emigrated from the troop.