Photograph by JEFFREY KERBY, Nat Geo image Collection
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A young gelada monkey clings to its mother in the harsh environment of the Ethiopian highlands.

Photograph by JEFFREY KERBY, Nat Geo image Collection

These tough-looking monkeys eke out a living at 11,000 feet

Think life is hard? Imagine eating grass, sleeping on cliffs while hyenas wait to kill you, and doing it all in rain, sleet, and snow in Ethiopia’s highlands.

With regal manes, hairless scarlet chest patches, and intimidating canines jutting from their mouths like scythes, it would be easy to think gelada monkeys were the rulers of their mountain domains.

That would be wrong.

No one gets off easy on nature's grasslands.

To understand just how difficult survival can be on a treeless grassy landscape, consider the world of the gelada, sometimes called the bleeding heart monkey. This primate spends its days searching for calories in low-quality vegetation on the high savanna along Africa's roof. Nights are for cowering in the cold and rain while clinging to steely straight basalt cliffs. In between there are fights, frights, and endless flights, from predators real, and, sometimes, imagined.

"We've always thought of them as leading pretty harsh lives," said Peter Fashing, an anthropologist with California State University, Fullerton, who with fellow primate expert Nga Nguyen has helped oversee a gelada research project in the Ethiopia Highlands for almost 15 years.

It's hard to argue with that.

Many enemies

Theropithecus gelada is neither a lone beast nor a hunter. The world's only grass-eating monkeys are, in fact, highly social and almost entirely vegetarian (if you discount the rare, lucky cache of insects). Found only in Ethiopia's highlands, often above 11,000 feet, they are what's left of a genus that millions of years ago stretched through Europe, central Asia, and all of Africa. It's still not entirely clear how many there are, with estimates ranging from tens of thousands to a few hundred thousand. (Read more about the author's experience observing geladas in the field in his recent magazine story.)

Spend a Day With the World’s Only Grass-Eating Monkeys

These monkeys are bulk feeders, sliding on their rumps during the day, grunting and squeaking and ripping out herbs and stalks of festuca grass. It's a hard way to make a living. Geladas spend more time eating than almost any other primate. And eating all day with your head down can make a monkey vulnerable. Just ask student researcher Bing Lin.

Lin worked for a time at Fashing's and Nguyen's research camp, a 42-square-mile stretch of high meadow overlooking the Great Rift Valley, a day's drive from Ethiopia's capital city, Addis Ababa. Scientists everyday track the lives of hundreds of geladas. They study relationships, monitor social squabbles, record new births and deaths.

In April of last year, Lin was alone, following a group of monkeys as they ate in tall tussocks. Suddenly he heard an intense gelada alarm call—a shrill echoing shriek. Monkeys raced past him into the shorter grass. A few minutes later, a leopard sauntered out, an adult gelada in its mouth. Lin happened to have a camera, and took pictures from 100 meters away.

"A few seconds later, the leopard suddenly stopped and looked around and noticed my presence for the first time, squarely locking eyes with me for several heart-stopping moments," Lin told me. Then it took off, leaving the dead gelada behind.

Death is never far for a gelada. Scientist and photographer Jeffrey Kerby, who spent almost a decade working at the gelada project, once watched a tawny serval make off with a baby monkey. Wild domestic dogs frequently kill them. Fashing has seen gelada finger nails in the feces of hyenas. Scientists have seen the pack killers gathering in groups below geladas' sleeping cliffs.

But even when predators aren't a problem, geladas still have to worry about each other—and us.

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Geladas must be wary of potential predators, from leopards to hyenas.

Human threats

Geladas form close communities, with groups of females bonding in reproductive units usually led by one male. Scientists believe the males' monster teeth have evolved as a product of sexual selection. The males use them to fight over females in battles that are as loud and fraught as they are vicious. When adult males go to war, the biting and wrestling can lead to blood. When new males take over groups, they may even kill another male's newborns.

But gelada gripes come in all varieties. Lin once watched a female bite off a quarter of another's ear. He saw a male shredding the upper lip of a rival. "These kerfuffles happen almost daily," he said.

Humans wreak their own havoc.

The community surrounding Fashing's research site, called Menz-Guassa, near Mehal Meda, is growing. Cars and trucks regularly pass. Fashing only knows of one roadkill monkey, but that road is being paved and powerlines have arrived in many places. In the meantime, geladas who raid nearby farms, where Ethiopian villagers grow lentils, potatoes, and barley, sometimes return with metal snares clamped around a limb.

And Guassa is one of the most conservation-minded communities in all of Ethiopia. Villagers here have banded together to protect their grass from poachers and overgrazing. In the other regions where geladas live, monkeys aren't always so lucky. Already, the vast majority of Ethiopians live among the deteriorating moors and thickets of the highlands, and the country's population is expected to rise 1,000 percent in the next 30 years from what it was in 1950. Sprawling agriculture and nearly 100 million head of cows, sheep, and goats plow through topsoil and native plants.

Protect the Grass, Save the People (and the Monkeys)

Geladas increasingly are pushed to smaller and smaller plots of land. While Guassa's monkeys feast on 60 varieties of plants, some other populations can go months on nothing but dry, brown grass.

"We didn't know they could even survive on that," Fashing said.

Sheltering together

So given this difficult world, geladas should be forgiven if they can seem a tad skittish.

When predators approach they've been known to let out distress calls, and then huddle together in a tight band. Often that panic turns out to have been driven by a quick motion from a harmless animal.

Where other primates might scamper up trees to flee, the tallest vegetation here is often giant lobelia and torch lilies. So these monkeys run and hide on massive cliff faces that can be a mile and a half away.

In fact, one of Kerby's favorite memories is of his early days working with the monkeys. The animals, at the time, were still suspicious of him and tended to keep their distance.

One day, a massive rainstorm rolled in. Lightning crackled over the plateau. Then the hail started to fall, and Kerby took shelter beneath a rocky overhang.

To his surprise, several geladas wandered over and sat next to him beneath the ledge. The monkeys sheltered there, hands clasped, looking into the distance "in that very peculiar way they do," Kerby recalled. Then the rain let up and the geladas returned to the meadow, the youngsters whining as they traipsed gingerly across cold, hail-strewn grass. Some even walked on their hind legs, Kerby said, until their mothers scooped them up.

For a brief instant the wall between scientist and subject dissolved.

"We were all in the battle against the elements together at that moment, our own evolutionary pasts momentarily forgotten," he said.

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