The most common monkeys kept as pets are marmosets, capuchins, squirrel monkeys, tamarins, spider monkeys, and macaques. Of these, marmosets are the most frequently bought and sold, partly because of their small size and relatively low purchase price. But “can” is doing a lot of heavy lifting in that question. Owning a pet monkey is legal in some U.S. states and banned in others, costs hundreds of dollars a month in ongoing care, and comes with serious behavioral and health risks that most people don’t anticipate.
Species Most Commonly Kept as Pets
Marmosets are the most popular pet primate by a wide margin. Common marmosets weigh under a pound and fit in the palm of your hand, which is part of their appeal. Baby marmosets are sometimes misleadingly sold as “pygmy marmosets” or “finger monkeys,” but true pygmy marmosets are a different, rarer species. Marmosets typically cost $1,500 to $2,500 from a breeder and can live up to 17 years in captivity, though many die much younger.
Capuchin monkeys are the next most common. They’re larger, smarter, and significantly more expensive, running $5,000 to $7,000. Capuchins are the species you’ve probably seen in movies or on social media. They can live 40 years or more, which means buying one as a young adult is a commitment that could outlast a mortgage.
Squirrel monkeys are small, active, and relatively common in the pet trade, typically priced at $9,000 or more. They can live into their early 20s. Spider monkeys cost $6,000 to $14,000 and are among the most difficult to keep because of their size, strength, and need for space. Macaques range from $4,000 to $8,000 and can live 30 to 40 years, but they carry a uniquely dangerous disease risk (more on that below). Tamarins, close relatives of marmosets, are similarly small and priced in the $1,500 to $2,500 range.
Where It’s Legal to Own One
There is no single federal law banning private ownership of pet monkeys in the United States. A bill called the Captive Primate Safety Act, which would prohibit interstate sale and transport of primates as pets, has been introduced in Congress multiple times, most recently in 2025, but it has never passed.
Legality depends entirely on your state. Some states ban private primate ownership outright, including California, New York, Colorado, and Georgia. Others allow it with a permit, and a handful, like Texas, Nevada, and North Carolina, have relatively few restrictions. Even in states where ownership is legal, your city or county may have its own ban. You’ll need to check state wildlife agency rules and local ordinances before purchasing.
The Real Monthly Cost
The purchase price is the smallest part of the financial commitment. Monthly care costs run between $200 and $1,000 depending on species and size. Food alone can account for $100 to $1,000 per month because monkeys need fresh fruits, vegetables, insects, and species-specific nutritional supplements, not just commercial pellets. Feeding a capuchin or spider monkey properly is closer to feeding another person than feeding a dog.
Veterinary care is the wildcard expense. Most vets don’t treat primates, so you’ll need an exotic animal specialist, and visits typically start at $500 or more. Pet insurance runs about $50 per month but varies by species. You’ll also need to budget for enclosure maintenance, enrichment toys, and potential home modifications. Over a 30-year capuchin lifespan, total costs can easily reach six figures.
Aggression After Sexual Maturity
This is the issue that catches most pet monkey owners off guard. Baby monkeys are affectionate, clingy, and dependent. That changes dramatically once they hit puberty. In macaques, males begin showing increased aggression around age three, directing it at other males and increasingly at their human handlers. Females go through their own behavioral shifts around the same age. Sexual behaviors start appearing one to two years before full reproductive maturity, meaning your “baby” monkey may begin mounting, displaying, and becoming territorial well before you expect it.
Capuchins follow a similar pattern. A capuchin that was gentle and cuddly as an infant can become unpredictable and aggressive by age five. They’re strong enough to cause serious bite wounds, and their canine teeth are built for cracking nuts. Many pet monkeys are surrendered, re-homed, or kept in increasingly isolated conditions once this stage hits, which only makes the behavior worse. There are very few sanctuaries that accept former pet primates, and most are already at capacity.
Psychological Harm From Isolation
Monkeys are intensely social animals. In the wild, they live in groups ranging from a handful to several dozen, depending on the species. Classic primate research demonstrated decades ago that monkeys raised without their mothers or without social contact develop severe psychological problems: self-mutilation, blank staring, repetitive circling, refusal to eat, and an inability to interact normally with other monkeys even when later introduced to a group.
Pet monkeys are typically pulled from their mothers within days or weeks of birth so they’ll bond with humans, a process called hand-rearing. This creates the very attachment that makes them appealing as babies, but it deprives them of the social learning they need to develop normally. A single monkey living in a human home, no matter how much attention you give it, does not have its social needs met. You are not a substitute for a troop. Many pet monkeys develop compulsive behaviors like rocking, over-grooming, or self-biting that are direct analogs to the disturbed behavior documented in isolation-reared primates.
Disease Risks for You and the Monkey
Because primates are so genetically close to humans, diseases pass between the two species with unusual ease. Bacteria, viruses, fungi, and parasites can all jump the gap in either direction.
The most alarming risk involves macaques specifically. Up to 90% of adult macaques carry a herpes virus called B virus. In the monkeys, it’s usually harmless or causes minor mouth sores. In humans, it causes a rapidly progressing brain infection that is fatal about 70% of the time. Most documented human cases have come from bites or scratches. If you’re considering a macaque, this is not a theoretical risk.
Tuberculosis goes the other direction. Monkeys are highly susceptible to human TB and can contract it from their owners or from exposure in any environment where human TB is present. A monkey with TB can then transmit it back to other people in the household. Other transmissible infections include salmonella, various intestinal parasites, and other viral diseases that both species share because of their biological similarity.
What Daily Life Actually Looks Like
Monkeys cannot be housebroken. They can be diaper-trained to a degree, but most owners report ongoing issues with urination and feces throughout the home. Monkeys also need several hours of direct interaction and stimulation every day. Leaving a monkey alone while you work a normal schedule is a recipe for destructive behavior and psychological decline.
Enclosures need to be large, secure, and enriched with climbing structures, foraging opportunities, and rotating toys. A marmoset needs a minimum enclosure far larger than any standard cage sold for birds or small mammals. Larger species like capuchins and spider monkeys need room-sized or outdoor enclosures. Many owners convert entire rooms or build dedicated outdoor structures, then find that the monkey still shows signs of stress and boredom.
Travel becomes complicated. You can’t board a monkey at a kennel. Finding a qualified pet-sitter is difficult, and many monkeys react badly to changes in their routine or handler. Veterinary emergencies can mean driving hours to reach a specialist. The daily reality of monkey ownership is far more restrictive than most people imagine when they see a cute baby marmoset on social media.
Species Comparison at a Glance
- Marmosets: $1,500 to $2,500, up to 17 years, smallest and most commonly sold, still develop behavioral issues
- Tamarins: $1,500 to $2,500, similar size and lifespan to marmosets, slightly less common in the trade
- Capuchins: $5,000 to $7,000, can live 40+ years, highly intelligent, significant aggression risk after maturity
- Squirrel monkeys: $9,000+, live into their early 20s, very active and need extensive space
- Spider monkeys: $6,000 to $14,000, large and strong, need the most space of any common pet species
- Macaques: $4,000 to $8,000, live 30 to 40 years, carry B virus with a 70% fatality rate in humans
If you’re seriously considering a pet monkey, the most important step is spending time with adult monkeys, not babies, at a sanctuary or with an experienced owner. The baby phase lasts a year or two. The adult phase lasts decades.