Meet Dennise Oritz
Primate Conservation Limelight
Dr. Dennise Oritz
Dennise Oritz’s resumé reads like an odyssey chronicling Costa Rica’s rich biodiversity. Graduating with a degree in veterinary medicine from the Escuela de Medicina y Cirugía Veterinaria San Francisco de Asís in 2020, her journey has taken her to many wildlife rescue centers across her native Costa Rica. At each one, she has honed her skills by treating an array of diverse species, from majestic toucans to serene sloths and enigmatic tapirs.
In 2022, Dennise came to work at Kids Saving the Rainforest (KSTR), a non-profit organization dedicated to the preservation of Costa Rica’s rainforests. As their Veterinarian/Health Wildlife Manager, Dennise found herself at the heart of Quepos, working in a role as dynamic as the ecosystem she serves. “We see all kinds of animals,” she says, “From spider monkeys, capuchin monkeys, sloths, parrots, kinkajous, and even sea turtles!”
Founded in 1999 by two nine-year-old visionaries with a passion for rainforest preservation, KSTR has since blossomed into a multifaceted organization with its own rescue center, clinic, and sanctuary. It’s clear the organization understands how healthy habitats and healthy wildlife go hand-in-hand.
When she recounts her serendipitous journey to KSTR, Dennise smiles. Eight years prior, while studying best practices for sloth rehabilitation, she volunteered at the non-profit. “I visited many rescue centers during that time,” she recalls, “but KSTR left an impression.” Little did she know that her dedication and expertise would circle back to this organization, years later.
“It’s a dream come true,” Dennise muses, reflecting on her transition from volunteer to integral team member. “To work alongside a passionate team making a tangible difference for Costa Rica’s wildlife—it’s truly rewarding.”
Despite never envisioning herself working with primates, Dennise’s breadth of experience provides her with a unique perspective on these complex creatures. “Primates are different,” she chuckles, “Their social dynamics make them both fascinating and challenging to work with – especially in terms of rehabilitation. But it is imperative that the monkeys in our care return to the wild so they can fulfill their crucial ecological roles.”
NEPC recently had the privilege of interviewing Dennise, who shared her insights on primate conservation and told us about some of the projects KSTR is currently spearheading that will focus on Costa Rica’s native primates. From the outset, it was clear how her expertise lies at the intersection of veterinary science and primate conservation, offering valuable insights into the practical connections between these fields.
Having worked closely with monkeys now, I am always surprised by their behavior and how intelligent they are—also, how resilient! They manage to survive even when humans disturb their environments. Of course, not all can adapt. But I find it interesting to think about the reasons why some populations are able to adapt to these changes while others cannot.
I oversee operations at the KSTR sanctuary, clinic, and nursery. So, my day begins with organizing. I have to organize what needs to be done in the nursery and sanctuary with their respective coordinators and also plan out the day in the clinic. Tasks in the clinic always include treating and checking up on the patients that we currently have in recovery. This includes those who are in rehabilitation as well as fully recovered patients who will soon be released. We have to feed these animals. But, to stimulate the animals mentally and physically, we also give them enrichment. Enrichment just means we try to be creative with how we give them food. Maybe we hide their meal inside natural materials so they have to use their brains to get to it.
I also get calls to make rescues, and when a rescued animal arrives at our clinic we have to do a full physical examination before deciding how to treat their ailments. Then we decide what the destination of the animals could be. Will they go to the nursery? The clinic? The sanctuary? Will they be released? Do they need to be translocated? Or, if a patient has died, do we need to do an examination to find out why?
They have always fascinated me, however, I had always envisioned myself focusing on other species. But having worked closely with them now, I am always surprised by their behavior and how intelligent they are—also, how resilient! They manage to survive even when humans disturb their environments. Of course, not all can adapt. But I find it interesting to think about the reasons why some populations are able to adapt to these changes while others cannot.
We have four primate species native to Costa Rica: Geoffroy’s spider monkeys, white-faced capuchin monkeys, black-crowned Central American squirrel monkeys, and mantled howler monkeys. Where we are, there are not many spider monkeys, since this species really needs primary forest to live. Our squirrel monkeys are endangered.
In the 1990s, it was common for people in Costa Rica to keep monkeys chained up so tourists could take pictures with them. Right now, we have two spider monkeys who endured this for many years. One was chained up, and the other was used in a circus. Both remain very affected by their experiences. One of them, Nina, is around 33 years old and has been here for 15 years.
It is not common anymore. Fortunately, the wildlife laws in Costa Rica have changed a lot since then and our government is very strict about enforcing them. That doesn’t mean there aren’t still monkeys illegally kept as pets or that are trafficked, but it does mean there are consequences when they are caught.
Unfortunately, she needs to stay in captivity. Mainly, because of how strongly she identifies with humans. She is really smart, and she understands she is not like other monkeys. In the presence of humans, she is too calm.
Monkeys who end up in captivity are usually taken when they are just babies. So, Nina was probably taken from the wild when she was very young. As a pet, she never learned how to be a wild spider monkey and so imprinted on humans instead.
When primates don’t develop with their own species, they get confused about who they are, and sort of end up seeing whoever happens to be around them as family, in a way. Unlearning that takes time, as does relearning their own species’ particular social dynamics. They’ll need to understand these dynamics in order to survive in the wild. They have to know, for instance, how to treat the leader of a troop; who grooms whom, and when; and what roles females play in the troop, etc.
Sadly, it happens sometimes that the monkeys we release don’t make it simply because the alpha in the troop doesn’t accept them—enough to lash out and kill them. It’s sad for us, and we always wonder if we could have done more, but that’s just how the wild works sometimes. They get killed because they didn’t know how to act in that particular social situation and there wasn’t necessarily anything we could have done to better prepare them.
Primates come to us for many reasons. Sometimes they’ve been hit by a car; sometimes they’ve been electrocuted; other times they’re found as orphans or might have been someone’s pet. The rehabilitation process really depends on the individual’s specific case.
In general, and most importantly, we want the monkey to be afraid of humans. Yes, we know monkeys are really cute and very smart but, for the monkeys’ sake as well as our own, we don’t want them to think of humans as potential friends. If they see a human, we want them to have the instinct to run or hide.
We also need to make sure that the monkey is able to find shelter. That’s really important because, if they are not able to find shelter on their own, they could die of exposure or from hypothermia.
And, of course, as we already talked about, there is making sure monkeys understand the social rules of their species. We actually have something really nice that happens at our sanctuary where wild troops of squirrel and capuchin monkeys come and interact with the monkeys in our care through the fence. This is meaningful because it doesn’t happen at many other sanctuaries and it means our monkeys can see, first-hand, members of their own species modeling proper wild behaviors. It’s almost impossible to teach these sorts of behaviors to the monkeys as humans.
We are fortunate that this happens at our sanctuary because the monkeys we release—even though we don’t typically release them in this area—will have better chances of being accepted when it comes time to join a wild troop. We try to release them where they were found because, if they had been living there a while, they probably know their area really well and probably even have family there.
When humans keep monkeys in captivity—as pets or for entertainment—they deprive them of playing their natural ecological and social roles. In addition to supporting the members of their troops, monkeys play an important role in their ecosystems by spreading the seeds of the fruits they eat.
This natural process is crucial to regenerating healthy forests. In other words, wild monkeys do naturally what humans often have to force themselves to do. Many people like to call primates “Gardeners of the Forest” for this reason. They do important work for us, for free, if we just let them.
KSTR does a lot for Costa Rica’s wildlife. But one project I’m involved with currently is to research how a certain parasite is spreading in primates in the Puntarenas region. The genus of this parasite, Prostenorchis, is known for its long protruding mouth covered in small spines. The spines help the parasite latch onto the wall of their host animal’s intestine. Even when you deworm the animal, the adults will survive and remain attached, so the only way of getting rid of them is by performing an invasive surgery. We have to open up the abdomen of the infected monkey and remove each parasite by hand. We have to make sure we get all of them because, if we leave just one, it will lay more eggs and the process will start all over. It’s terrible! Last week, we did surgery on a monkey where we removed around 85 parasites—that’s a lot for a two-pound (1 kg) monkey!
For individuals, it’s not a pleasant experience. When the parasites attach to the wall of the intestine, they cause a reaction in the monkey’s body. The body knows something is there that shouldn’t be and floods the area with white blood cells. This causes growths, or nodules, to form. Feeling for these nodules is one way we can identify if a monkey is infected.
If it remains attached for long enough, a parasite can make a hole in the intestine. When this happens, the abdominal cavity can become severely infected. Sometimes, when this happens, you can’t tell that a monkey is sick until they suddenly stop eating and die. I mean suddenly, as in: they stop eating today and die tomorrow.
On a broader scale, at least in other countries, for example in Brazil, studies have shown this parasite is decreasing the population in other monkey species—marmosets, I think were the subject of a study I was reading. The extent to which this parasite affects primate populations in Puntarenas will be one of the subjects of our study.
We have also been noticing that the parasites like to attach really close to the caecum, a special pouch connected to the junction of the small and large intestines. So, we also want to find out why this is.
We need to take action because if this parasite continues spreading in the long term, not just individual monkeys but entire populations could be at risk. One action we are taking is to document our treatments and report their success rate so that other veterinarians and conservationists can replicate them elsewhere where this may be becoming a problem.
We actually have something really nice that happens at our sanctuary where wild troops of squirrel and capuchin monkeys come and interact with the monkeys in our care through the fence. This is meaningful because it doesn't happen at many other sanctuaries and it means our monkeys can see, first-hand, members of their own species modeling proper wild behaviors. It's almost impossible to teach these sorts of behaviors to the monkeys as humans.
We know the parasite spreads through cockroaches and some beetles, but there might be even more insects involved as carriers, not to mention other factors we’re not aware of yet. Through our research, we want to look into which insects carry the parasite and why. There are also multiple types of cockroaches in Costa Rica, so we need to determine whether they are all potential carriers or if only certain kinds are.
We’re curious, too, about the extent to which human activities contribute to transmission. In other areas like Santa Rosa, Guanacaste, for instance, where there is more primary forest, this parasite hasn’t been as prevalent as it is here. Quepos, being a particularly touristy location, sees a lot of human interaction with the forest, whether that’s due to nearby hotels or other tourist attractions. Our hypothesis is that the parasite is more common in areas with significant human presence and interaction.
Normally, this parasite would only be a concern for captive animals. But we’re seeing more and more cases in wild animals. Something that happens a lot in Costa Rica, especially in tourist areas, is people feeding wild animals.
And, though we know the parasite’s genus is Prostenarchis, we still need to determine the specific species we’re dealing with in this area.
Yes, if they are treated in time. We just need to make sure they are okay, of course. Last year, we did surgery on a monkey that had something like 19 parasites and he recovered really well. He started eating the very next day, and we were already able to release him within about 20 days of his surgery.
Monkeys are really tough. I think they may be the toughest animals that I have ever met. Really. Sometimes, when we do a necropsy to find out how a monkey died, we discover so many parasites that we are all shocked that the animal could have survived for so long in that condition.
I wish people knew the important role primates play in their ecosystems. Many species act as engineers of the forest and are key to creating a healthy environment. Also, by studying them, we are able to understand our own species’ evolution better. Because humans are primates, after all.
I also want people to know about the wealth of information we can gather from a simple fecal sample. We can find out about an animal’s family tree, diet, microbiome, stress levels, immune system levels, parasites, and countless other things just from a piece of poop. And it’s a completely non-invasive procedure!
Most of all, I want people to understand that primates should never be kept as pets. There are a host of reasons why but perhaps the most convincing is how extremely dangerous it is to have close contact with them since, being some of course closest relatives, any diseases they happen to be carrying can easily crossover and infect humans. And vice versa.
I think everyone, anywhere can become a primate or a wildlife conservationist. One of the most important steps is to learn about the situation with wildlife and why they are important for our health and well-being. Most people probably don’t ask themselves what would happen if we didn’t have wildlife, let alone how they help keep our environments healthy. People who make the effort to learn this information can help us on the ground by helping us spread awareness, even if it’s just to their friends and family.
The more research we do, the better we understand how we can help primates and how best to protect them.
MORE ABOUT KIDS SAVING THE RAINFOREST
Interested in collaborating with Kids Saving the Rainforest? Contact Dennise Oritz at [email protected]
To donate: https://www.kidssavingtherainforest.org/?form=DONATE
