- The buffy-headed marmoset is down to no more than 2,500 individuals scattered across dwindling patches of Brazil’s Atlantic Forest.
- It faces a range of threats, from yellow fever to climate change, but the biggest one is hybridization with other marmoset species released into its habitat from the pet trade.
- Conservationists working to save the species warn that populations are declining rapidly, with little funding for studies or captive-breeding programs, and a lack of political will under the current government to act urgently.
- One possible conservation solution is to establish “safe haven” forests for unmixed buffy-headed marmosets that will exclude hybrid animals, but this will difficult and costly, experts say.
I’ve been writing about wild things for more than 10 years, and while there are many animals I don’t know, I thought I’d at least heard of most of the world’s primates: monkeys, lemurs and apes. And then a conservationist sent me a photo of a buffy-headed marmoset (Callithrix flaviceps). My response: Holy bananas, what the hell is this?! How did I go 40-plus years of obsession with wild things and never hear of this kitten-sized, sad clown-faced monkey?
It turns out I wasn’t the only one. The species is barely known to locals in its native Brazil, and until very recently had little direct attention from conservationists. That is until Rodrigo Salles de Carvalho and his group, Mountain Marmosets Conservation Program (MMCP), decided to focus on the species a few years ago along with Brazil’s National Center for Research and Conservation of Brazilian Primates (CPB) as well as Chico Mendes Institute for Biodiversity Conservation (ICMBIO) who write the national action plan, or PAN, for a threatened species’ recovery. MMCP had long been working to conserve the buffy-tufted marmoset (Callithrix aurita), which inhabits similar regions, and the more they learned about the buffy-headed marmoset the more concerned they grew.
Over the last few years, Carvalho, his team at MMCP, and collaborators have come to realize that the buffy-headed marmoset is in dire trouble. The IUCN Red List recently changed its status to critically endangered, and scientists estimate its population is no bigger than 2,500 animals (and likely less than that). Ever heard of Glenrock, Wyoming? Me neither. But more people live in that small town than there are buffy-headed marmosets in the world. Not only is this sad clown-faced marmoset among the most endangered mammals in Brazil — it’s probably one of the most endangered primates in the entire world.
The buffy-headed marmoset looks a little like an aging clown: the black markings around its eyes a little smudged, perhaps, as though its hands trembled as it put on its makeup, its hair sticking out at the sides like an uncombed mop.
“They have a very charming mocha coffee outfit,” Carvalho says. “To exchange glances … with [their] quite vivid eyes is an outstanding experience.”
Still, when I first saw the photo, I couldn’t help but think the buffy-headed marmoset looked a little melancholic, like a diva whose best days are behind her. But it’s a melancholy I find appealing. This sad-clown version of a marmoset was enough for me to want to dig deeper — and find out what’s happening to these little relatives of ours.
It’s not good.
First off, these marmosets live in a small region of the Atlantic Forest in Brazil — one of the most imperiled ecosystems on the planet, with about 11-16% of the ecosystem surviving. Add on top of that: the species is being smacked by yellow fever, climate change and, worst of all, hybridization with invasive marmoset species, a recent issue that may turn out to be the buffy-headed marmoset’s doom.
The species needs swift and aggressive action to safeguard its survival, but that requires money and support. Given that few people have heard of this animal, Carvalho says his group struggles to get the required funding. Moreover, the Brazilian government of President Jair Bolsonaro has hardly proven itself conducive to conservation and environmental issues.
The sad-clown marmoset is walking a tightrope.
The sad-clown marmoset
Marmosets are a diverse group of 22 tiny monkey species found in South America, including the world’s smallest monkeys (the western and eastern pygmy marmosets, Cebuella pygmaea and Cebuella niveiventris). They are a part of the Callitrichidae family, which includes the other super tiny monkeys, the tamarins.
The buffy-headed marmoset is unique for a number of reasons. First, as noted, its milky coloring and markings are quite head-turning. It is also one of only two known marmosets that inhabit higher-altitude areas, somehow able to survive chilly heights. Finally, it has the smallest range of any marmoset, covering just 28,500 square kilometers (11,000 square miles) of the states of Espírito Santo and Minas Gerais in southeastern Brazil.
Buffy-headed marmosets also have a wide palate, eating fruit and gum, but also lots of insects, small birds, frogs, and even eggs. Seasonally, research has shown that the buffy-headed marmoset even has a taste for fungi!
Seeing the little monkeys in the wild, however, is nearly impossible.
Carvalho describes them as shy compared to most other marmoset species. Indeed, he’s only seen them a few times in his work in the forest. The team usually employs prerecorded calls of other buffy-headed marmosets to see if they can lure them into view to assess the population.
“When finally, they respond to our playback calls and we get to see them, we get fascinated and joyous as children receiving Christmas gifts,” Carvalho says. One time, he was lucky enough to see a troupe of about 10 animals, a surprise since biologists didn’t expect buffy-head marmoset groups to contain that many individuals.
“They make this sound like a bird. They’re really fast-moving. I would say they’re really beautiful animals,” says Carla B. Possamai, the coordinator of the Primate Community of Caratinga project, where she has been tracking populations of buffy-headed marmosets.
Yellow fever and other existential perils
Attempting to list the number of issues impacting the buffy-headed marmoset is daunting. But let’s start with the most obvious: the Atlantic Forest, or Mata Atlántica in Portuguese, is a fractured, shrunken and broken ecosystem. Once spreading across 1.2 million km2 (463,000 mi2), humans have whittled it down to just a fraction of its original area.
Since the arrival of the Portuguese in the early 1500s, the forest has succumbed to massive urbanization — the region is home to some of Brazil’s biggest cities, including São Paulo and Rio de Janeiro — intensive agriculture, monoculture plantations, cattle ranching, and mining. Nearly all of what remains is in patches, enclosed by cities, towns, and farmland. As deforestation continues, many species here are on the verge of vanishing.
So that’s where we start in the 21st century. But the marmosets might be able to hold on, at least for a while longer, if they didn’t face three other major threats: disease, climate change and, most pressing of all, hybridization.
The buffy-headed marmoset is one of only two marmoset species that inhabit mountains, making them more adapted to the cold. But like all higher-altitude species, climate change poses a threat. As mountains warm, cold-specialist species are pushed higher and higher until there is literally nowhere else to go. Researchers don’t know yet how much of an impact climate change is having on this species, but they remain alert and concerned.
Then there’s yellow fever. It hit the region in late 2016, absolutely decimating populations of primates in the Atlantic Forest patches. Farmers told conservationists that “the forest went silent.”
Possamai was monitoring a 1,000-hectare (2,500-acre) private reserve during the yellow fever outbreak, cataloging northern muriqui or woolly spider monkey (Brachyteles hypoxanthus), the largest monkey in South America and also critically endangered, for the Muriqui Project of Caratinga. The site had also been home to around 200 marmosets, but after the yellow fever outbreak, Possamai didn’t see any. The project, in response, expanded from looking for just muriquis to surveying for a number of primates, including the buffy-headed marmoset. For months, Possamai searched, playing back the marmosets’ squeaking call over and over. Nothing.
Possamai was beginning to believe that the species had vanished altogether from this forest until one day in October 2017, when two buffy-headed marmosets appeared out of the canopy.
“Before [the yellow fever outbreak], there was this one specific place in the forest that tourists used to go and the [marmosets] would come. They were very easy to see,” Possamai says, noting that one group was particularly famous for hanging out and entertaining tourists. “Now, it takes sometimes a couple of months to find them,” she says.
Indeed, after that first sighting, Possamai didn’t see the marmosets again for another three months.
Currently, this particular patch houses just 17 animals, spread over three family groups. It’s not nothing, but hardly what it was pre-yellow fever outbreak. While the population here appears stable, it does not seem to be rebounding.
“I’m really worried about it,” Possamai says.
As if all this weren’t enough to deal with, the buffy-headed marmoset is in danger of completely disappearing due to hybridization.
The hybrid problem
For a while in Brazil, marmosets were all the rage as pets. The “pets” were primarily common marmosets (Callithrix jacchus) and black-tufted-ear marmosets (Callithrix penicillata) taken from the wild and sold in markets.
The traders would ply the monkeys with alcohol so they appeared “very nice [and] very kind” to customers, says Cecília Kierulff with the National Institute of the Atlantic Forest, or INMA. She describes the process as “horrible.” Customers would take the drunk monkey home, and after a few hours, the marmoset would “freak out,” according Carvalho.
Not only was the monkey no longer sedated, but it was suffering from an awful hangover.
“After we started working with the marmosets, everybody said, ‘Oh, when I was a kid, my uncle gave me a marmoset.’ Thousands of stories like that,” Carvalho says. “Of course, 90% were released back into nature.”
Once people realized that what they’d bought wasn’t a cute, docile pet, but a feral, wild animal, they would dump the marmosets in the nearest forest. But these forests already had marmosets: buffy-headed marmosets.
The invasive former pets began breeding with the buffy-headed marmosets, producing hybrids. Very quickly, populations became entirely hybridized, genetic mix-ups of various marmoset species.
Kierulff says it’s easy to tell the difference between hybrids and unmixed buffy-headed marmosets once you’ve had some training.
“When you see a group where each one is different from the other, completely different, then something is wrong,” she says.
And the hybridization can happen fast, the conservationists say. Really fast. One year, researchers are concerned about disease and deforestation, and the next they suddenly notice that the marmoset juveniles no longer look right.
“If there’s one hybrid, just one hybrid entering in a protected area, it’s horrible,” Kierulff says.
The hybridization problem has become so bad that the researchers view it as the biggest threat to the species. And there isn’t an easy solution.
In the past, conservationists may have turned to culling to get rid of hybrids. However, the conservationists here don’t feel that’s the way to go for a number of reasons. Many are against it for ethical reasons, and even those that would consider it don’t feel the Brazilian public or policymakers would support outright killing of the hybrid marmosets. A more palatable idea that’s being discussed may be sterilizing hybrid animals.
Currently, though, Carvalho says he’s putting all his energy into identifying “safe havens” — forests that could be actively maintained to keep any invasive marmosets out. His group, MMCP, is mapping and analyzing different forests, both public and private, looking for potential sanctuaries. They’re seeking forests that lack connecting corridors and ones whose borders could be, at least somewhat, controlled. None of this will be easy or cheap.
Saving the sad-clown marmoset
If the group can identify “safe haven” sites they will need to make agreements with either the government, if it’s a public forest, or landowners, if private. They will then need to establish numerous controls to attempt to keep any invasive marmosets out.
“Every politician speaks about conservation [in Brazil] but real money [for] conservation … we don’t have it,” Carvalho says. “Park managers also know they will have a big fight to get the minimum money to make it happen.”
Kierulff adds that the Bolsonaro administration is cutting funds for “research, science, for everything.” Funding for student research and work is also vanishing, imperiling conservation work across the country.
Currently, most of MMCP’s money comes from foreign zoos, such as the Beauval zoo in France and the French Association of Zoological Parks, or AFdPZ.
“It was because of them, we survived,” Carvalho says, adding that his group is working on expanding its revenue stream. The fact that MMCP is funded largely by zoos is not surprising: Zoos are often some of the only institutions willing to fund the direct conservation of lesser-known species.
Another idea: captive breeding. Currently there are no buffy-headed marmosets in a captive-breeding program, meaning that if they vanish from the wild there are no captive populations to avoid total extinction and leave options open for rewilding.
“All the specialists agree that we need a captive population,” Kierulff says. But that, too, will require funding and time, both of which are running out for the sad-clown marmoset.
It’s not supposed to be this way. Primates are supposed to be easy to protect, right? They’re mammals, charismatic, and our closest relatives. The buffy-headed marmoset, in addition, is ridiculously cute — something that usually translates well into conservation attention and action. However, research in 2017 found that six in 10 primates are threatened with extinction, and 75% are seeing their populations decline. Many, like the buffy-headed marmoset, are receiving nowhere near the required conservation attention.
If we can’t save an animal as splendid as the buffy-headed marmoset, what does that mean for the millions of other less “charismatic” species on Earth? And what does that say about us?
“They need minimal money just to survive,” Kierulff says of the buffy-headed marmoset.
Like an increasing number of species today, the buffy-headed marmoset is at a stage where it requires human action in order to survive at all. It doesn’t need humans to just leave it alone — a conservation tactic that has worked for many species in the past. It needs humans to intervene. It needs us to act. Will we? Or has the sad clown begun its last act?