It was Ebony who kept the family together, in the face of vicious slaughter and unspeakable tragedy. She was the last matriarch of the Hardwoods, a group of elephants that George Wittemyer and his colleagues have been getting to know since 1997.

When he first met the Hardwoods at Kenya’s Samburu National Park, they comprised three core families led by four old females, each over 40 years old. Three of them—Teak, Mahogany, and Sandalwood—were killed between 2001 and 2002. “The survivors maintained strong bonds through all of this, at times staying together closely for months, as if they were one single large family,” says Wittemyer. “I think this was driven largely by the leadership of Ebony.”

She was a singular elephant. Even though she had survived a gunshot wound and had lived through the death of three sisters, “she never displayed anger towards us,” says Wittemyer. “She passed down that attitude to her daughters and nieces. Taking her lead, the Hardwoods have become one of the calmest groups in the park.”

Ebony was killed in 2011. By the time the researchers found her body, it had already been decaying for weeks. There were multiple bullet wounds in her head, and an AK-47 bullet lodged in her skull. Her death was part of a long season of intense poaching, which started with a drought in 2009 and carried on until 2014. “We have so many stories of this terrible process: watching elephants being born, growing up to become mothers in their own right, and then dying for their teeth,” says Wittemyer. Between 2010 and 2012 alone, more than 100,000 elephants were killed in Africa for their ivory.

If these losses are painful for researchers, consider how catastrophic they must be for the elephants themselves. These are highly intelligent animals with strong social ties. What’s more, the old matriarchs—the ones who are most likely to be killed for the size of their tusks—are repositories of knowledge and wisdom. There’s good evidence that they are better at leading groups, more effective atdistinguishing threats, more knowledgeable about defensive moves and survival tricks. During a drought, calves are more likely to survive if they’re in groups that are led by older matriarchs.

Each dead matriarch leaves an elephant-sized hole in the world. Perhaps her daughters can never truly fill it.

What happens to these leaderless groups? Do they rebound? Reform? Collapse? To find out, Wittemyer’s team plumbed the data they have collected over the last 16 years about the Samburu elephants, including social associations between more than 100 individuals. They used this information to reconstruct the pachyderms’ social networks at three periods of time, including the most recent bout of intensive poaching.

Even though the population experienced a 70 percent turnover during this time, the survivors would reform around the oldest remaining females, recreating new networks with the same basic structure as the old ones.

“We kept on seeing these associations that didn’t make much sense to us. We’d say: Why are these elephants hanging out, when they’re not in a close group together?” says Shifra Goldenberg from Colorado State University. “But we looked backed and saw that their mothers knew each other. The family ties are maintained by their daughters across generations.”

African elephants form nested societies. Females will hang out with a core group, consisting of her closest relatives. When these cores get too big, they’ll split into smaller groups that still maintain ties—these are called “bonds.” And when bonds get too big, they also split, forming “clans.” Goldenberg and Wittemyer found that the core and bond groups were very similar after the poaching epidemic as before. “We saw those groups recreated,” she says. “Females who were previously associated at a bond level reached into their core group to create a new bond group.”

The clans, however, disappeared. “We think that’s because the clans represent associations between really old females, who spend their whole lives together.” Think of them as separate branches of the same extended family, united by the same grandmother. If the grandmother dies, the different groups have no reason to hang out any more.

David Lusseau from the University of Aberdeen isn’t surprised by any of this. “Mothers die; that’s a fact of life,” he says. “Passively, daughters become mothers, and old mothers die leaving daughters as the new older females. The big issue isn’t whether social-network integrity is at risk, but the age of the matriarch.”

Phyllis Lee, the director of science at the Amboseli Trust of Elephants, agrees. “The question remains: Will elephant families be effectively led when they concentrate and follow a teenage matriarch?” she says. “That families can cohere around someone, anyone, with some leadership capacities is an important finding. But cohesion alone will not solve the reproductive consequences of the currently accelerating loss of experience in older females.”

“We think this is a happy story but there are lot of other implications to losing your matriarch,” says Goldenberg. “And we could only study the elephants that we saw. There were probably others that disappeared because their families fell apart.” Each dead matriarch leaves an elephant-sized hole in the world. Perhaps her daughters can never truly fill it.

“The elephants continue to piece together their lives,” writes Wittemyer. “The young play with their age mates, siblings explore and develop new relationships out of a changed existence, and the adults lead their families through the hazards of life as best they can. And we too continue to record the data, hoping for the trend in our records to show signs of ebbing.”