Last Monday, Indianapolis Zoo staff alerted by an “unusual amount of roaring” raced to the lion pen to find a startling scene: Zuri, a 12-year-old female, had her teeth locked around the neck of Nyack, a 10-year-old male who had fathered her three cubs. Keepers tried to separate the pair, but Zuri refused to yield her hold. As the pair’s three-year-old daughter Sukari looked on, Nyack succumbed to the lioness’ vise-like grip, growing eerily still as the effects of suffocation set in.
The devastating attack has left zoo staff and researchers reeling. According to Reuters’ Daniel Trotta, the lions had peacefully cohabitated for eight years, even mating to produce three cubs—Enzi, Mashaka and Sukari—in 2015. Prior to the incident, neither Zuri nor Nyack had ever shown signs of aggression toward the other.
“[Zookeepers] build strong bonds with the animals so any loss affects us all greatly,” Indianapolis Zoo curator David Hagan tells Trotta. “For a lot of us, it’s just like a family member.”
It’s not unheard of for lionesses to attack males, Allyson Chiu writes for The Washington Post. Just last month, the BBC reported that a group of females housed at the West Midlands Safari Park in Worcestershire had ganged up on a male named Jilani following a disagreement over food. Jilani escaped relatively unscathed, although park staff noted that he was “stiff and sore” in the aftermath of the fight.
Craig Packer, director of the University of Minnesota’s Lion Research Center, further told Chiu that he has observed females attacking a nomadic male in the wild, typically in order to scare off the potential threat to their cubs.
But this latest incident is unprecedented, Packer says. Nyack was not only the father of Zuri’s cubs, but her longtime companion. It’s also surprising that Zuri engaged in a one-on-one attack, as lionesses generally band together when targeting males.
In an interview with BBC News’ Ritu Prasad, Packer explains that the pair’s personalities likely played a major role in the attack. Although males tend to dominate females in the wild, zoo enclosures encourage a different power dynamic. As a hand-reared lion, Nyack may have been more vulnerable than most males. Comparatively, Zuri was more domineering than the average female.
According to the Indianapolis Zoo’s website, Zuri, who is described as an “attentive and protective mother,” weighs about 325 pounds—just 25 pounds less than Nyack, who is deemed ironically vocal for such a laid-back lion.
Anna Moser, a wildlife ecology and animal behavior expert at the University of Minnesota, tells NBC News’ Farnoush Amiri that the pair’s status as captive animals also could have contributed to the violence. In the wild, males tend to leave their cubs after about two years, leaving females in charge of the offspring.
Paul Funston, southern Africa regional director of global wild cat conservation group Panthera, expands on this line of thought in an interview with Live Science’s Brandon Specktor, explaining that the couple’s three-year-old cubs had reached a crucial point in their lives. If they’d lived in the wild, the two males, Enzi and Mashaka, would’ve left their mother to pursue new mating opportunities, while the female, Sukari, would’ve joined Zuri’s pride in order to prepare for her own future as a mother. This newfound independence, Funston says, would mean that Zuri was free to mate with Nyack once again.
Unfortunately, if this was the case, Nyack’s courtship went unheeded. It’s possible he approached Zuri aggressively, leaving her feeling threatened. Or maybe Zuri was unable to mate due to a contraceptive given by zoo staff. With tensions rising, “fighting got intense and, the next thing, she killed him," Funston hypothesized.
The Washington Post’s Chiu notes that the attack actually happened in two stages. The first time Zuri attacked Nyack, he escaped. The second time, however, he wasn’t so lucky.
According to an official necropsy, Nyack died of suffocation triggered by injuries to the neck. As Packer tells The Indy Star’s Kellie Hwang, this kill method is unusually vicious.
“That's the way they kill their prey," he said. "The fact that it's such a lethal thing, right at his throat, again that's surprising. When [lions] usually go after each other, they are happy to just wound each other.”
Zoo staff will likely never know exactly what happened in the lion pen on that fateful Monday. Zuri and her cubs remain on view, and the incident is under investigation.
But as Packer explains to NBC News’ Amiri, no one could’ve foreseen such a singular act of violence occurring, so it will be difficult to pin the blame on any specific party or practice.
"All of these animals are unpredictable moment to moment," Packer tells Hwang. "The main lesson here is … that it's something that can happen. If you have that combination of an aggressive female and submissive male, it might not be the ideal configuration."