No abstract

A heritable positive and causal relationship will have been selected between pairbond strength and stability and reproductive success if a male-female pair bond has been the major unit of reproduction during the evolutionary history of a population. All the descriptive studies reported on pair-bonding birds and on humans are consistent with this evolutionary deduction. Pair-bonded individuals with poor reproductive success are predicted to alter their behavior so that their reproductive success is increased or so that their inclusive fitness is increased through kin selection. Specific examples of these alterations are elaborated for a monogamous and territorial population. Five hypotheses are formulated so that the assumptions on which the deduction is based may be tested experimentally in specific subject populations of animals.

No abstract

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.

A method for understanding how patterns of range use are related to either environmental or to social factors is first to assess quantitatively characteristics of the patterns with descriptive indices, and second, to use appropriate univariate or multivariate methods to determine the proportion of variation in the patterns associated with immediate ecological or social factors. This paper is focused on methods for quantitative assessment of two characteristics of patterns of range use: the degree to which occupational densities of areas within a range are clumped and the degree to which occupational densities within a range are consistent over time. The method of analysis of patterns of range use advocated in this paper is compared with other, previously used methods.