Most mammals, including primates, pass through three stages--infant, juvenile and adult. Here are some general ways in which most nonhuman primates species--capuchins (Cebus), spiders (Ateles), macaques (Macaca), and so on, change as they grow and develop: More often than not, the success of longtime monkey keepers seems to be in the development of an attitude of tolerance toward nonhuman primate behavior, including aggression.
INFANCY--In infancy primates are helpless and therefore dependent on someone else for survival. They require round-the-clock care by their own mother or a human surrogate and generally have compliant attitudes for the first several months.
As monkeys grow, they start gaining independence, similar to other growing mammals or to a human toddler. They need to experiment and investigate the world around them and will usually begin to push away a helping hand.
JUVENILES--With adult life on the horizon, the juvenile stage is a preparatory one. Play-fighting and play-mating are two typical behaviors. A juvenile female may carry another monkey's infant in a colony, or carry a stuffed toy in captivity as a practice infant. This is the ideal time for monkeys to learn their status or place in the social hierarchy Play is a good testing ground, especially for juveniles, and monkeys can become rougher in their play with you as they grow.
Many primates have a natural desire to dominate, and some have a stronger tendency in this regard than others as they mature. A monkey may bite simply as an easy way to say "no" to someone or something, but it is not always easy to determine the reason why a monkey has bitten. At the same time a monkey may become more aggressive from time to time, he may also be developing a more gentle, loving, sensitive and responsive side to his personality. Also, as juveniles mature, the bond between mother or parent and child weakens. This varies in human relationships with hand-raised monkeys. Some monkeys remain more affectionate and attached than others.
ADULTS--Increased strength comes as capuchins, spider monkeys, macaques and larger monkeys mature. (By comparison, strength is not significant in small nonhuman primates like bushbabies, marmosets and squirrel monkeys.) Along with maturation comes the cunning and ability to manipulate their environment, unlock or open heavy doors, take their waist belts off, get into the refrigerator, open or even break windows and numerous other abilities and scenarios. You will probably not know a monkey has developed the ability to do something, until her or she surprises you by doing it. For example, an adult spider monkey (Ateles) can drag a couch or a picnic table with his or her tail and one macaque was strong enough to pull the hair right out of his owner's head when she chastised him for breaking eggs.
The transition to adulthood takes longer in some species than others. Here are some behaviors found in wild-living adult monkeys, which we can see duplicated or find some variations in pet monkeys: Touching, hugging, affectionate leaning or snuggling, mouthing, lip-smacking, vocalizing, greeting, sexual mounting, sexual activity, sexual displays, mothering or parenting behavior, urine scenting, dominant or possessive or protective behaviors, grooming, aggressive displays or threats, biting, pinching, hair pulling, intimidation, aggressive or play chasing, temporary social alliances, long-term social alliances and so on.
Here are a few courses taken by monkey owners, as they deal with maturing monkey:
One seasoned monkey owner with a positive attitude says, "From my elbows to my hands, I am covered with little scars, the work of monkey hands and teeth, some done in rough play and others in aggression. But even the scars are dear to me, made by the monkeys I have loved....."
Monkeys and their personalities are individual, just as the personalities of their owners are. There is no blueprint for sharing your life with a monkey, but here are some techniques for working with some primate behaviors. These will probably work best on monkeys kept from juvenile age or younger and are offered as suggestions that will work with varying success, depending on the monkey and surrounding circumstances.
As a general guideline, use language and develop trust. Again, the better your relationship at every stage, generally the easier it will be to get through the harder "teenage" and early adult stages.