All of them.
Monkeys are illegal as pets in the USA
Here's why:
So you want a pet monkey?
Is it possible for monkeys to receive excellent quality care and enjoy a fulfilling lives as pets? Yes, but realize first that monkeys are complex social/emotional animals that can best be termed as "high-care/high-need", "difficult" pets. Difficulty levels vary between species and individuals, larger monkeys generally being more problematic in some respects and smaller ones in others. In reality, it is unlikely that most people will be the highly motivated, committed caretakers required to provide for a monkey's lifetime needs.
Did You Know:
1. Prosimians, monkeys, apes and humans are all primates. We share many characteristics and we share diseases. As our closest relatives, non-human primates can transmit mild to highly dangerous diseases to their owners, their owners' family and friends. Diseases like the common cold, internal parasites, hepatitis A, tuberculosis and even the often fatal Herpes B virus.
2. Non-human primate ownership can be regulated at the local, state or national level. Even if legal at the state level, numerous cities and counties have made it against the law to keep pet primates; illegal possession can result in fines and confiscation of the innocent victim, your pet.
3. To be made into a "pet," baby primates are taken away from their mothers when only hours or days old. Evolved to have continual (24 hr/day) body contact with their moms, infant primates are left to hug towels or stuffed animals. Depression is not restricted to human primates, these infants and mothers typically suffer depression from the forced separation.
4. Infant females taken away from their mothers' care don't develop the parental skills necessary to raise their own young. A vicious cycle of rejected infants that must be raised by humans in order to physically survive is started.
5. Primates are social. Under natural conditions they live in social groups and have constant companionship. Now think about the number of minutes per day you spend with other pets such as a dog. Thirty minutes? Two hours? Primates need more, much more. Once the decision has been made to remove the infant primate from its mother's care in order for it to become Your pet, You become its social life. Planning to have a job, go out with friends, see a movie, shop? Continuing to lead your normal life and leaving your pet to spend the majority of its day alone is both unnatural and inhumane.
6. Given good care and proper nutrition, non-human primates can lead very long lives. Twenty five to 30 years is not unusual for the smaller species while macaques, baboons and spider monkeys can easily reach 40 and apes can live to be 55 years old. A high school senior who buys an infant macaque can get a job, get married, raise a family and become a grandparent before the pet macaque dies of natural causes. Most people are not able to make that type of life-long commitment to a domestic pet yet alone a challenging exotic pet.
7. Once they reach sexual maturity, non-human primates become more unpredictable and dangerous. Even small primates are deceptively strong and all primates have damaging canines. Gentle one minute, they can inflict severe wounds when suddenly frightened, surprised, confused or frustrated. Owners are often shocked and feel betrayed. Believing they should not risk further aggression, responsible owners typically make the decision to reduce contact with the pet.
8. Non-human primates that become emotionally bonded to their owners, a trait that pleases and is encouraged by the master, can become jealous and attack visiting family, friends, neighbors, new boy/girlfriend or even the mailman. Owners can be held responsible for resulting medical bills and may be subject to lawsuits. Vacations could be out of the picture; finding a qualified caretaker who is accepted by the pet primate and willing to risk chance of being bitten may prove impossible.
9. Many small animal veterinarians do not want to accept the risk of injury or disease transmission and will not treat non-human primates. Additionally, few have the training to provide expert care.
10. Non-human primates are intelligent, curious and active. Unless caged, they can destroy furniture, curtains and any household decorations. They can throw their food around and easily rip off their diapers and soil the house.
11. Tired of dealing with the array of problems caused by pet primate ownership, most owners end up wanting to get rid of their pet. Lacking infant appeal, adult non-human primates are difficult to place. They may be transferred from inadequate to bad to worse homes, bought by an animal dealer or sent to an animal auction, shot or euthanized. Exotic animal sanctuaries are at capacity, zoos don't have the space for former pets. Rarely is the story ending a happy one.
12. Baby primates raised to adulthood by humans have not acquired all the necessary social skills to live with others of their own kind. If an owner is able to convince a sanctuary or roadside zoo to take his pet, integrating the imprinted primate into a peer group can be life threatening. Sending inappropriate signals to its new and strange companions, the former pet can be harassed, intimidated, and even attacked. If accepted, ex-pets can nevertheless remain social outcasts, individuals who through no fault of their own are caught between two worlds and can't live successfully in either. Neurotic behavior and depression are common consequences.
13. You may be the best pet-primate owner in the world, but by purchasing an infant primate, you are perpetuating a business that leads to miserable lives for many of the very animals you profess to adore.