The Elusive Saki Monkeys Are One Of The Best Things You've Never Seen

Have you heard of saki monkeys? It wouldn’t be surprising if you hadn’t – they’re incredibly elusive, and unless you live deep in the Amazon rainforest, you’re unlikely to see one even by accident.

But you really ought to know more about them. Not only are they fashion icons, they’re also incredible athletes and so tricksy as to have at one point disappeared for the best part of a century.

Oh yeah – and they can fly.

What do saki monkeys look like?

Saki monkeys are a genus, not a species, so they have quite a range of characteristics. Like any group of evolutionary cousins, though, there are some commonalities: the long, bushy tails, for example, which, unlike many of their fellow New World monkeys, are not prehensile – they’re just used to aid balance while running and jumping.

Sakis are pretty small, measuring approximately 30–50 cm (12–20 inches) without the tail – and up to double that length if you include it – and weighing only about two kilograms (4.4 lb), give or take a few grams.

But it’s not their size, or even the tail, that makes these monkeys iconic. It’s the fur coat.

“Sakis have long, rough hair that covers their entire body, giving them a distinct shaggy look and oftentimes they appear to have ‘bangs’,” notes the University of Michigan Museum of Zoology’s Animal Diversity Web . “Sexual dimorphism varies among species, but males and females generally have distinct pelage markings.”

For some types of saki, like the white-faced saki, those pelage markings can be quite striking indeed: males of that species are marked by – you guessed it – a bright white face, standing stark against the animal’s black fur.

And if a stylish saki gets flustered, watch out – that characteristic mane “can raise into hackles and make them look bigger than they actually are when they feel threatened,” the ADW adds. Add to that an alarm call that can deter predators from even trying to attack, and it’s clear these little monkeys aren’t the defenseless critters they seem at first glance.

Where do they live?

As New World monkeys, sakis live in, well, the New World: their habitat extends from the bottom of Colombia all the way down to central Brazil and Bolivia; from Peru all the way across to the Eastern shores of Guyana. And they’re not that picky about their living conditions, either – as long as there are trees for them to hang out in, they’re happy.

“Sakis exist in a variety of habitat types, including lowland to highland forests, relatively dry to seasonally flooded forests, primary to secondary forests and disturbed forests,” notes a factsheet about the white-faced saki from the European Association of Zoos and Aquaria (EAZA) – though, understandably for animals whose diet is up to 90 percent fruit and seeds, they “prefer areas with an abundance of watering holes and fruit trees.”

Once they find their home, though, they stick with it. Saki monkey habitats tend to have clearly defined and exclusive boundaries, usually spanning about 10 hectares – that’s just under 25 acres, or around three-quarters the amount of space that the Pentagon takes up (which is fitting, since a group of monkeys is called a troop). They live in relatively small family groups, spending a lot of time grooming their loved ones, and have been known to accept “immigrants” to their troops.

They’re also homebodies in the z axis, too, spending almost all their time between three and 25 meters above ground (that’s 10 to 82 feet for American readers) and coming down to ground level only to search for food.

At night, they stick to their sleeping trees, where they adorably curl up like a cat amongst the branches. And – wait a second.

A small and elusive mammal? Long tail used for balance while running and leaping? Likes to spend its time up high, only coming down for food? Enjoys being groomed by family members? Responds to threats by puffing up its fur and yowling?

This… this is just a vegan cat, isn’t it?

Are saki monkeys endangered?

No, but it’s complicated. Saki monkeys are, like all the most sensible animals, pretty elusive – that vertical range they favor is particularly lush with foliage cover, and they can spend up to 12 hours a day hidden behind the leaves. They’re what’s known in ecology circles as “cryptic” animals – no, that doesn’t mean they’re related to Nessie or Bigfoot, it just refers to the fact that they blend in really well with their surroundings – and they play that to their advantage: if one in a group sees a potential threat, they sound an alarm call and the whole troop goes motionless, fading visually into the canopy.

It's a great survival tactic, but it makes tracking their conservation status a real ballache. “There is a data deficiency for almost all saki species,” the ADW notes, “and current populations are unknown.”

That said, we’re pretty sure their populations are trending down – and the reasons for that are as depressing as they are predictable. Deforestation in the Amazon is devastating their habitats – not only reducing it, but also leaving it fragmented across their once-wide ranges.

More directly, the monkeys are also targeted for their meat, or for the exotic pet trade – so, while their populations are generally considered to be safe for now, there’s a lot to keep an eye on in the future.

Why should I care about saki monkeys?

Because, frankly, they’re pretty dang cool. We’ve already covered their wild shaggy locks and predator-alarming yells, but get this: they can also fly.

“Sakis use their long fluffy tails […] to help steer as they leap breathtaking distances through the treetops,” wrote conservation photographer and author Christina Selby in a 2017 article for bioGraphic . They can jump up to 10 meters, or more than 30 feet, “earning them the moniker of macacos que voo , or monkeys that fly.”

How impressive is that? Well, it’s the equivalent of an average-height US man leaping around four times the distance of the world record long jump. And – oh yeah: it’s all happening 20 meters in the air.

But as remarkable as that athletic prowess is, it’s nothing compared to the rings these little critters have been able to run around human researchers. Thanks to their shyness around potential predators, the relatively under-explored places they live, and, frankly, disorganized fieldwork, the knowledge base around saki monkeys has traditionally been – and this is a technical term – “chaotic”.

In fact, the elusive nature of the saki monkeys has been shown to an almost comical degree. In 2017, director of the Global Conservation Institute and leading saki monkey expert Laura Marsh set out to discover one species of saki monkey – the Vanzolini bald-faced saki, or Pithecia vanzolinii . It was a big ask, but not outside of her wheelhouse: she had already identified five new species of saki just three years previously, so the statistics were on her side.

“To find the missing monkey, Marsh and a team of scientists, photographers, conservationists, and local guides set out on a four-month-long expedition into a little-explored part of the western Amazon,” reported National Geographic at the time. “They set sail in a small, two-story houseboat and headed up the Eiru River, near Brazil's Peruvian border.”

What made the discovery such a big deal? Well, here’s the thing: this monkey wasn’t a new discovery. It had first been seen in 1936 by the ornithologist Alfonso M. Olalla, who sold specimens of the sakis to natural history museums in Sweden and Brazil. A few more were collected in 1956, again being sent to museums in Brazil.

But other than that? Nothing. “The monkey hadn't been seen alive in 80 years,” National Geographic explained.

So you can imagine the excitement when, after all that time in the rainforest, facing down the intense deforestation and cynical hunting of monkeys, Marsh finally caught a glimpse of the beautiful, golden saki.

“When Marsh first saw the monkey after years of anticipation,” National Geographic reported, “she burst into tears.”