A troop of the Japanese Macaque consists of several adult males, adult females (two or three times the number of males) and their babies, total 5-30 individuals or sometimes more than 100 individuals.
They are in constant motion in their territory (several kilometers in radius). Females remain in their natal troop, usually in her entire life. Most of males move to another troop during young age, they have several troops in his entire life.
There is a strong bond between the members, especially among females and their babies. They do not bow down to the power of any specific monkey. They trust and rely on each other.
However they have skirmishes as a matter of daily practice and are injured often. It is nature that there are strong monkeys as well as weak monkeys. There is a dominance hierarchy in a troop. The highest ranking male is called boss of the troop. Not only males but also females have ranking.
The offspring of high-ranking females inherit their mothers’ ranking.
Among brothers and sisters, younger one gets higher ranking under his/her mothers’ sanctuary. Ranking exists to avoid unwanted fights in the troop. This does not mean that high-ranking monkeys control the lower-ranking monkeys.
Monkeys mainly get information by eyesight. Also they communicate each other through sights. They read partners mood with seeing their expression and attitude.
Although it is not quite language, they have some typical sounds such as alarm, intimidation, yelp and signal of existence etc. They express their feelings by differences of tone and volume. Firstly they make sounds to get attention and then confirm with eyesight. Monkeys have better hearing and sense of smell than human, and use five senses, mainly eyesight, to live.
For monkeys in a troop, it is very important to understand each other.
They always care about members’ attitude and the atmosphere in the troop. This is the same that we call ‘Read between the lines’. Monkeys have an amazing ability for it.
In the society of the Japanese Macaque, both males and females have many partners in a breeding season. Females know own mother-child relationships between their infants but there is no father-child relationships. Neither males nor infants know their own father-child relationships. That’s why males do not get engaged child-raising.
Only mothers breast-feed infants and stay together all the time to guard them from dangerous. But this is only for infants of one’s own and for immediate family. They do not care if other infants are in a danger. In that case males help such infants. Males have the role of father for all members of the troop.