Why alpha females reign supreme in meerkat world
As a corner of Africa heats up, new research shows how the future of the species rests with powerful matriarchs making tough choices for survival.
One brisk morning last August in South Africa’s Kalahari Desert, a female meerkat weakly pulled herself from her burrow, tail dragging slowly behind. She joined her family members as they foraged for grubs, but she was too sick to eat. Nearby, carved in the auburn soil, lay a terrifying clue: the long, sinewy tracks of a puff adder. She had been bitten.
Even though meerkats measure just 12 inches tall and weigh no more than two pounds, they can typically withstand snake venom potent enough to kill an adult human. Still, a large dose can be dangerous.
That day, the bitten female’s fellow meerkats banded together to find extra food for her. When they returned to their burrow at night and realized she’d been left behind, they turned around, calling for her. They wouldn’t let her perish, in part because she was critical to their survival. She was the dominant female—and sole breeder—of her small clan.
(Rising heat puts the Kalahari’s ecosystem on the edge of survival.)
Meerkats live in a matriarchy. They are one of only a few mammals, including spotted hyenas and lemurs, that have social structures built around female dominance. That ailing female meerkat was the one in her multigenerational extended family that birthed the babies and kept others strictly in line. As the group’s leader, she maintained social order over her clan of helpers, which embark on daily foraging trips, guard against predators, and watch over the pups. Without her, the group would struggle to both find enough food and protect itself.
Matriarchs have a distinct set of advantages that help them rule. They are larger, stronger, and more aggressive than their subordinate counterparts. Over the past 10 years, research has revealed that these traits are linked to high levels of hormones like testosterone. It’s also sharpened our understanding of how the roles alpha meerkats play are more vital than ever as conditions become harsher in southern Africa, one of the world’s most rapidly changing environments.
The meerkat that suffered the puff adder bite and her family live in Tswalu Kalahari Reserve, a nearly 300,000-acre wildlife preserve along the southern edge of the Kalahari Desert. During the past two and a half decades, Tswalu has been rewilded from overgrazed farmland and repopulated with herds of antelope, lions, cheetahs, and other native wildlife. The park, which has three luxury safari camps, is one of the few places in the Kalahari where meerkats have been habituated to the presence of humans and can be approached for close observation. That’s due largely to Olorato Moacwi, a 29-year-old tracker who monitors the meerkats’ movements from sunup to sundown.
Meerkats typically thrive in groups of 12 to 15 adults, but the meerkat clans Moacwi follows in Tswalu are precariously small. This winter they numbered a mere five, six, and seven individuals apiece. Such low numbers make the clans more vulnerable to dying off. They have fewer members to forage, stand sentry watching for predators, and rear young. Smaller clans live on the very edge of survival, with little buffer from everyday dangers and even less from the looming existential threat of extreme heat waves and drought.
Since the late 1990s, high temperatures in this part of southern Africa have skyrocketed by over two degrees Celsius—a more dramatic rise than in most places on Earth outside of the Arctic and Antarctic. The number of summer days that reach the upper 90s Fahrenheit has more than tripled. More directly threatening than heat, though, is drought, because it cuts off the meerkats’ food supply. Less rain means fewer insects, pushing the meerkats to travel farther and dig deeper in the ground in search of sustenance.
Roughly 50 miles west of Tswalu lies the Kalahari Research Centre, a private ranch where biologists study the lives of thousands of meerkats and where much of the scientific knowledge of the species comes from. In 2012 and 2013, a severe drought killed off more than half the site’s meerkat population. “Droughts are really what kicks the meerkat population down,” says Tim Clutton-Brock, a zoologist at the University of Cambridge and National Geographic Explorer who founded the Kalahari Meerkat Project, which is located at the ranch.
And rough stretches in the region seem to be getting longer. Today the meerkats at the site are about 10 percent smaller than they were in the 1990s. In addition, even the biggest groups now count 20-something meerkats, while before the drought they numbered in the 30s and 40s.
The extreme hardships brought on by climate change can make a meerkat matriarch resort to brutal survival tactics. Earlier in the winter, Moacwi noticed that two meerkats in one of the clans she was following were pregnant at the same time. When food is scarce, a pregnant matriarch will prioritize her own pups—and put her considerable physical advantage to use. When the subordinate gave birth, the dominant female savagely attacked the other meerkat mother, nearly ripping off her lower jaw, and killed the newborn pups. She then threw the subordinate out of the clan. For a month, the exiled female haunted the edges of the group, foraging and sleeping alone. Only after the dominant female’s own pups were born was the exiled female allowed back into the family.
That level of viciousness by a meerkat matriarch may seem extreme, but it can work in the group’s favor. Christine Drea, a behavioral ecologist at Duke University, and her team discovered in recent years that a dominant female’s testosterone levels nearly double during pregnancy. The matriarch uses that surge of strength and aggression against anything that might threaten the survival of her pups and, by extension, the clan’s future—like a food shortage brought on by long droughts and brutally high temps. “The nastiest female is the one that will have the most surviving offspring,” Drea says.
Meerkat matriarchs like that one hold the keys to the species’ resilience. Meerkats’ sometimes cooperative, sometimes competitive social structures let them adjust and adapt, even in the face of insect shortages and unrelenting droughts. “The meerkats recover very well,” Moacwi says. At winter’s end, the largest clan she tracks welcomed two litters of pups, doubling the group’s count to 14. As for the matriarch that had been bitten by the puff adder, she pulled through, thanks to the help of her family. Moacwi saw her a few weeks later, back in charge—and pregnant.
