Table 1.
Individual information on the eight Japanese macaque infants whose facial development and behavior were monitored.
Fig 1.
Example of landmark plots on the frontal face view of Japanese macaque infants.
Table 2.
Definitions of Japanese macaque infant facial landmarks evaluated in this study.
Table 3.
Facial parts and inter-rater reliability of the measurements.
Table 4.
Summary of the six facial measurement indices calculated for the analysis of facial development in Japanese macaque infants.
Table 5.
Description of the five behavioral milestones observed during Japanese macaque infant development.
Fig 2.
Comparisons of each facial feature between infant, juvenile, and adult Japanese macaques.
Horizontal lines indicate significant differences between age classes. See text for significance levels.
Table 6.
GLMM results comparing the facial index between age categories in Japanese macaques.
Fig 3.
Developmental changes of IFS in Japanese macaques of all ages.
The ages of adults were included as whole numbers (years, integers), while the ages of infants and juveniles were included as their age in days divided by 365.
Table 7.
GLMM results examining the association between IFS and affiliative contact duration with caregivers of Japanese macaque infants.
Fig 4.
IFS development of each infant within the first 24 weeks of life.
Black lines and gray ribbons represent the estimated values and 95% confidential intervals. The circles and triangles indicate females and males, respectively.
Fig 5.
Facial appearance of each infant at three different stages: (a) newborn, (b) between approximately 41 to 72 days of age, when IFS peaked for some infants, and (c) around 1 year after birth. In (a), the youngest facial photographs of each infant were shown.
Fig 6.
The age with estimated IFS peaks and the first-observed age in days of the five behavioral milestones in the eight Japanese macaque infants observed.
Certain information is missing due to the temporary suspension of observations.