Preliminary study on eye colour in Japanese macaques (Macaca fuscata) in their natural habitat

摘要: Eye colour in Japanese macaques shows apparent differences between individuals, continuously ranging from orange (bright), through shades of yellow and hazel-blue to dark blue (dark). We arbitrarily classified them into either ‘yellow’ eyes or ‘blue’ based on the area occupying iris’ peripupillary ring. Most have after infant phase, whilst 19, 17, 12, 15% monkeys (>6 months, sexes combined) blue-eye studied two groups Shodoshima Takasakiyama, respectively. Frequency eye did not differ males females, but significantly differed each age class. Blue more frequently occurred newborns, infants aged than juveniles prime adults. Data mother–infant pairs indicated could be inherited their parents. A case asymmetric was found a sample 1962 individuals. variation discussed relation those humans rhesus macaques. possible evolutionary model discussed.