Abstract
A measure of cranial size is calculated for 15 samples of 11 macaque species by means of a principal component analysis of variancecovariance matrix of logarithmically transformed 17 cranial measurements. The sex difference of cranial size (CSSD) is defined as a ratio of male cranial size to female cranial size. CSSD shows a weak tendency of negative correlation with several body size measures, and a low level of positive correlation with body weight dimorphism. Associations of CSSD with mating patterns (Caldecott, 1986), relative testis weight (Harcourt, 1981), canine dimorphisms (Plavcan et al., 1995), maximum values of intrinsic rate of natural increase (Ross, 1992), weed or non-weed dichotomy (Richard et al., 1989), and female dominance style (Matsumura, in press) are all weak or insignificant. While CSSD ranges widely among the “paraphyletic” silenussylvanus species group (1.107-1.172), the CSSDs of the two “monophyletie” species groups minimally overlaps; 1.093-1.142 in the fascicularis species group and 1.142-1.160 in the sinica species group including M. arctoides. Sympatry among macaque species appears to strongly influence CSSD; 1.172-1.160 in tropical isolated species, 1.153-1.125 in sympatric heartland species, and 1.121-1.093 in subtropical or temperate isolated species.
