Wikipedia says:
"Because of their similarity to monkeys, apes such as chimpanzees and gibbons are often called monkeys in informal usage, though biologists don't consider them to be monkeys"
And if you consider keeping one as a pet:
"Although they may appear to be friendly and nice and can resemble human babies for some people, many people believe that monkeys should not be kept as, or thought of as, pets. While baby monkeys are usually as easy to keep clean as a human infant (by diapering), monkeys that have reached puberty usually remove their diapers and cannot be toilet trained. They require constant supervision and mental stimulation. They usually require a large amount of attention. Monkeys cannot handle being away from their owners for long periods of time, such as family trips, due to their need of attention. Bored monkeys can become extremely destructive and may, for example, smear or throw their own feces. There often needs to be a lot of time set aside for cleaning up messes the monkey might make. Most adolescent monkeys begin to bite unpredictably and pinch adults and children. Any surgical means to stem this behavior (such as removing the teeth or fingertips of the monkey) is widely considered cruel, and it is usually difficult to find veterinarians who will treat them: even exotic-animal veterinarians may not be familiar with them. Monkeys eventually have to grow up and may in many cases can become wild and difficult to control. The monkeys may also become aggressive even to their owners. In some cases their behavior can change from one minute to the next without warning — making it hard for the owner to fully understand or control them.
While a majority of monkey owners find other homes for them, such as zoos and monkey rescues, some people report having long and rewarding relationships with monkeys. Monkeys are known to get attached to their first owner, so switching from one to another can be traumatic to the monkey and may aggravate behavioral problems. It is not easy for a monkey to get used to a new environment. Monkeys need to be placed in social areas. It is bad for the monkey to place them in non-social environments, and doing this typically leads to problems. It is also expensive to care for a monkey — housing, food, and veterinary care can become very costly. Some monkeys have special needs such as diets."
Cheers
Reachy
