Rescue to the Research: An Update on Mateo the Spider Monkey
With the help of Mateo, the orphaned monkey Florida Tech helped to re-home in 2020, university researchers are learning about the complex social relationships of primates and how those dynamics may illuminate human behavior.
Mateo the monkey is living the good life. But it didn’t start that way.
Likely bound for the illegal wildlife trade until he was found in the center console of a truck attempting to cross the Texas-Mexico border in June 2020, he was rescued through the combined efforts of Florida Tech and Brevard Zoo.
After confiscating him, the officers who found Mateo contacted the U.S. Fish and Wildlife Service, who brought him to be quarantined at Dallas Zoo for a couple of months. In the meantime, the Association of Zoos and Aquariums Species Survival Plan set to work finding Mateo a new home, where he could—hopefully—integrate with a new monkey troop.
The organization quickly found one at Brevard Zoo, where associate professor Darby Proctor had recently developed a spider monkey cognitive testing complex, home to Shelley, the troop’s alpha female who already had an infant about the same age as Mateo and who, they’d hoped, would essentially adopt him. The only problem was getting him there.
At the time, commercial airlines, the usual transportation in these types of situations, were not flying nonhuman primates due to COVID-19 restrictions. But Proctor had a solution: FIT Aviation.
After much coordination, on Sept. 17, 2020, two FIT Aviation pilots and Brevard Zoo’s curator of animals took off in one of Florida Tech’s Piper Seminoles bound for Dallas, returning the next day with a safe, albeit exhausted, fourth passenger: Mateo.
He was introduced to the troop at the zoo, and this is where we left Mateo: without a primate caretaker when Shelley refused to let Mateo near her offspring. Researchers had thought Shelley would be a good mother for him, but she was, in fact, too good of a mom—determined to protect her babies from the new stranger.
“I think we did most of the interview about Mateo not very long after he had come here, and wow, did I get nervous at that point,” Proctor says. “He was not doing well at all.”
She says Mateo had been alone for a minimum of half his life, causing him to develop abnormally. Since he was not clinging onto his mom, his body shape was different, and the musculature of his legs did not develop the way it normally would.
“He also had this huge potbelly, which is indicative of not having a very good diet,” Proctor says. “He was in a bad nutritional state. He was terrified of other monkeys. Now, I don’t think even another expert could pick out which of our monkeys was that monkey, because he is doing so, so well.”
Mateo has completely integrated into the spider monkey troop at the zoo. He now spends his days looking after and playing with the other young monkeys and has shown healthy signs of development.
So, how did Mateo go from a scared, isolated infant to the healthy youngster seen today? For that answer, we have to turn to troop alpha male, Shooter.
An Unexpected Bond
After settling in at the zoo, Mateo was slowly introduced to the group of spider monkeys, meeting the other juvenile monkeys and the females first. He met the other males of the troop last, as researchers thought they would pose the biggest threat.
They couldn’t have been more wrong.
Upon meeting Shooter, Mateo was terrified. Shooter hung out near Mateo but did not approach him. After Shooter outstretched his arm, which is a reassurance gesture, Mateo curled into Shooter’s belly area, and Shooter protected him—like a mother would.
“It was one of the most beautiful interactions I’ve ever seen in my life, and I’ve worked with around 13 different primate species, including chimpanzees,” says assistant professor Catherine Talbot, who works with the spider monkeys at the zoo with Proctor. “The alpha male wound up adopting Mateo. Mateo sleeps with Shooter and follows him all around.”
While it is typical of the species for young males to want to spend time around adult males, it is rare for an alpha male to adopt an orphaned monkey. So rare, in fact, that it has never been documented, to Talbot’s knowledge, with wild spider monkeys before.
“There’s only very few cases in which we’ve seen any sort of adoption in captive environments,” Talbot says. “Shooter regulates the group when anyone’s getting rough. With infant spider monkeys, sometimes, their play gets a little rough, and then often, the mothers will come and intervene on behalf of their offspring. In this case, Shooter will do the same for Mateo.”
While the bond between Shooter and Mateo was unexpected, Proctor says Shooter may have seen a bit of himself in Mateo.
After Shooter adopted Mateo, Proctor obtained Shooter’s zoo records, which showed that at 9 months, he was integrated into a social group that he was not born into, giving him a similar background to Mateo’s.
“We cannot say this with any sort of scientific certainty, but I really wonder if Shooter remembers that,” Proctor says. “We know primates have robust long-term memories. Does he remember that? Is that why he was so open to helping this little monkey without a mom?”
Regardless of the reason, thanks to his new caretaker, Mateo is now growing and thriving, going as far as to show higher prosocial behavior than the other monkeys in his troop. Prosocial behavior is behavior that’s affiliated in nature, such as sharing of resources or initiating play.
Researchers noticed Mateo carrying other infants—something documented in only a few cases in the wild and usually performed by juvenile females—and protecting other young monkeys during rough play.
One monkey Mateo looks out for is his best friend, J, who was rescued in a similar way.
In fall 2021, a patrol officer found another young spider monkey at the Texas-Mexico border in a suitcase on the side of the road.
Named J after the first initial of the officer, Brevard Zoo went through a similar process to integrate him into its spider monkey troop.
J was younger than Mateo, but it was clear he had spent more time with his original spider monkey family, as he was good at communicating with the others.
“J was integrated into the troop, and Shooter essentially adopted J, as well,” Talbot says. “I would say that the bond between Shooter and Mateo seems to be a little bit stronger, but Shooter also looks out for J, and Mateo and J have become best friends.”
Mateo has also taken on the role of looking out for J and keeping him out of trouble.
“When some of the other juveniles are playing a little too rough with J, Mateo will come and almost drag the other individuals away to not bother J,” Talbot says. “It’s adorable.”
While everyone is glad Mateo is happy, healthy and adjusted, his arrival and interactions with the other spider monkeys has also helped to progress research.
Proctor says there isn’t a lot of research on spider monkeys in captivity, as most primate research centers choose capuchin monkeys because they have the biggest brain-to-body size ratio of new world monkeys—a rough proxy for intelligence across animals.
Through the Dr. Mary Helen McCay Research Shed and the Animal Cognitive Research Center, Proctor and Talbot perform research and gain new findings about the species. While there is a lot of evidence on spider monkey behavior in the wild, there is limited research on how they act in captivity.
“The advantage of doing research in a place like a zoo is that we can not only ask, ‘What do they do?’ But we can ask, ‘What can they do?’” Proctor says. “We have the research space out at the zoo, and I don’t know of any other place in the world that has a research space for spider monkeys.”
The Spider Monkey Complex at the zoo, where all of this is housed, is one of the only animal-managed fission-fusion habitats in the U.S. Fission-fusion is a social organization in which the troop breaks off into smaller subgroups throughout the day and then comes together into larger parties when resources are abundant or toward the end of the day. Humans also utilize this social structure.
Having an animal-managed habitat allows the spider monkeys to break up as they choose into the smaller subgroups and come back together when they feel it’s time.
Talbot says they are taking a closer look at the strength of these social bonds, and they are currently looking at social learning. The monkeys are being trained to exchange tokens as part of a project on inequity, where they are performing the same task but getting paid less than a partner.
The relationship between Shooter and Mateo also leaves room for a deeper exploration into spider monkey cognitive capabilities.
“We have a theory that the complexity of your social world helps to drive the evolution of cognitive abilities,” Proctor says. “That we’re seeing such complicated social behaviors, like an adult adopting a stranger infant, to me, suggests they have quite a bit going on up there that we haven’t been able to tap into yet.”
Mateo may have had a rough start, but he is on his way to becoming a well-rounded spider monkey and potential next alpha of the troop at the zoo.
“Mateo obviously had a really tragic start, but to me, I think he has had the best possible outcome,” Proctor says. “He’s in a complex social group with plenty of space and tons of enrichment. He has lots of other monkeys to play with. He is starting to show interest in sexual behaviors and approaching that context correctly. So, for a monkey with this tragic background, I don’t know what’s a better outcome for him than that.”
This piece was featured in the spring 2023 edition of Florida Tech Magazine.