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Monkey Mashup Matchup

By: Breanne Cyr, PI behavior specialist

Extra, Extra, Read all about it! We’ve recently had some new pairings and social group switch-ups!

Our two latest arrivals, Hanu and Ganesh, each came to us housed individually from a research facility. As far as we know, neither of them had lived with another monkey for years – possibly even many years. From the time they arrived to Primates Inc, we began watching their social cues, collecting behavioral data, and understanding their personalities to see who might make good companions with each of them. Around the same time, the dynamics between two of our existing pairs had started becoming less ideal than when the pairs had first formed. This created multiple monkeys ready to participate in the monkey mashup matchup to find new roommate companions.

The Backstory

We had initially paired Rocky with Junior. As you may recall, they had a positive relationship where Junior loved to groom Rocky. Rocky was a great teacher/role model and essentially taught Junior how to be a monkey, since Junior, a former pet, had never seen other monkeys. Rocky was very patient with Junior and allowed him to figure out how to communicate, including their differences between species. (Rocky is a rhesus macaque and Junior is a lion-tail/pig-tail hybrid macaque).

However, eventually Rocky started becoming very food dominant and realized he could take advantage of Junior’s submissiveness and eating habits. Rocky liked to eat everything all at once, whereas Junior liked to graze. However, because Rocky became a bit pushy with food, Junior became anxious to eat. Both monkeys ate in separate bedrooms, and we tried numerous interventions to address their food inequalities over the couple years they were together. Ultimately, although it was a tough decision, we decided to make a roommate change in order for Junior to sustain his nutritional needs.

At that point, Rocky moved across the hallway to live with Mars. Again, things mostly went well. In fact, we’d never seen Rocky or Mars groom another monkey before – each had only been on the receiving end of the grooming. Suddenly, both Mars and Rocky were grooming each other multiple times a day! For the most part, their relationship was positive. BUT…Mars was very fast and strong and Rocky did not have the quick and fancy moves like Mars. Mars sometimes forgot his strength, and was catching up to Rocky. While aggression is common and to be expected in rhesus macaques, most of it should not involve contact and is mostly used as an intimidation or reminder rather than a physical altercation. In order to protect Rocky from the times where Mars got a little too aggressive, we had to separate them after several months.

Monkey Matchup

Using our socialization tunnels, we gave our potential monkey pairs multiple “date” opportunities where each monkey could be in closer proximity to a potential roommate. We collected data about each pairs’ interactions and potential compatibility. Ultimately, we ended up with the following successful new roommates:

Rocky and Hanu

Hanu is our diabetic monkey. Because of his diabetes care, treatment, and health risks, Hanu needed a roommate who would be on the submissive side, easy going, and adaptable. Of course, Rocky came to mind, particularly when we discovered that he was submissive to Hanu. This would minimize stress for Hanu, and meanwhile, Rocky would not be able to become food dominant over Hanu. Excellent!

After about several months now, Hanu and Rocky like to sit next to each other and observe what we’re doing. They forage together nicely, without aggression. They haven’t gotten to grooming each other yet, but if they decide they want it, they’ll do it. Hanu is slightly dominant, but he’s very considerate and Rocky is very comfortable with him. Because they have different diets, they eat separately, which allows us to better monitor how much food Rocky is taking in and monitor how much of Hanu’s detested diabetes medication he consumes vs trying to hide it on the floor. Their spats have been minimal, although they do occasionally like to team up to try to take on their larger, more dominant neighbor, Izzle. Fortunately, this co-aggression is a bonding experience for Hanu and Rocky and for the most part, Izzle seems to enjoy having their company right next door (he gets upset when he can’t see them!)

Junior and Ganesh

Both Junior and Ganesh have arthritis and are slower to get around.  Additionally, they both have similar eating styles, where they eat their favorite foods right away and then graze throughout the day. Ganesh is dominant to Junior, but nonetheless, Ganesh is a gentle dominant and would likely be submissive to many other residents at Primates Inc. This is helpful to Junior so that he is not overly intimidated or anxious to eat.

After several months, Junior is eating well and getting more grazing opportunities now that he is paired with Ganesh. They are still working out their communication and how much proximity or grooming together they want. However, both monkeys are doing great, and even if they aren’t as obviously “friends”, we’ve seen that Ganesh will hold back and wait for Junior and they get anxious when they are separated for very long. Junior attempts to interact with Ganesh, but Ganesh often doesn’t know what to think – and we don’t blame him after so many years alone! It will take time, and fortunately, he can take all the time he needs in sanctuary life.

If you’re wondering about Mars, he’s doing well, too. We attempted to reunite him with his former pals, Batman and Timon, but their relationship had evolved as well, creating too much aggression. They are immediate neighbors, however, where they can be face to face or fingers to fingers through a mesh paneling. Mars is doing well with limited contact with Batman and Timon, such that he is able to safely benefit from some sociality and seems content with a good repertoire of “normal” activity and behavior.

Our behavioral data shows that the monkeys are exhibiting fewer stress behaviors and their activity is closer to that of their wild counterparts – a sign we look for to indicate a natural, “wild” environment. We will continue to observe the new pairs (and all the monkeys) over time and watch their relationships evolve. We collect behavioral data to ensure that we aren’t missing any signals that the pairs’ welfare hasn’t decreased.

We hope they continue building on their new relationships, but if they start getting impatient with one another, they can again befriend new roommates. We really want to give them the living conditions and choices that make each of them most content and allow them to live a peaceful and enjoyable sanctuary life.

Junior and Ganesha: Junior is black, Ganesha is grey


Hanu (back) and Rocky (front)


Hanu on ground, Rocky on table