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AAAS Member Craig Packer: Lioness Death at Zoo Cause for Concern

The Dallas Zoo is mourning the loss of one of its lionesses, five-year-old Johari (also known at Jo-Jo), who died on November 17 after being bitten in the neck by a male lion in her pride. Early news reports suggested two male lions where involved in the attack. The zoo is investigating the incident, which included a necropsy of the slain lioness. In the immediate hours following the attack, the lions were separated and taken off exhibit.

The pride at the zoo consists of two males, Denari and Kamaia (brothers), and three females, Johari, Lina and Josiri (sisters). All are five years old.

"She died very quickly, and there were no visible outward signs of trauma," the zoo wrote on its Facebook page. No zoo staff witnessed the attack. Many zoo patrons did, however, and some painted a dramatic picture—a male lion grabing the female by the neck and holding her down for 10 to 15 minutes before letting go of her lifeless body.

Zoo officials say the attack was seemigly unprovoked and Johari had not shown any visible signs of ill health (perhaps making her more vulnerable to an attack). Lions attacking pridemates is a rare occurance in captivity, according to Lynn Kramer, D.V.M., vice president of animal operations and welfare at the Dallas Zoo. "In my 35 years as a veterinarian in zoos, I've never seen this happen," he said in a statement posted on the zoo's website.

What could have caused one cat to turn on another? AAAS MemberCentral's Program Director Peggy Mihelich spoke with lion expert and AAAS member Craig Packer to get some further insight into this incident. Packer is a Distinguished McKnight University Professor in the Department of Ecology, Evolution and Behavior at the University of Minnesota. He has studied big cats in Africa since the 1970s, has published over 150 scientific papers, and his new book, Lions in the Balance: Man-eaters, Manes and Men with Guns, will be published in 2014.

AAAS MC: Right now the zoo is investigating the death of Johari. Based on your observations of wild lion populations, what might be the cause of this attack?
Craig Packer, Distinguished McKnight University Professor in the Department of Ecology, Evolution and Behavior, University of Minnesota: I've come up with a couple of speculations based on our observations of wild lions: For one, the victim might have been sick or otherwise behaving abnormally. During the 1994 canine distemper virus (CDV) outbreak in the Serengeti, we saw lions attacking pridemates who were having seizures, and I've also heard of a lion who was attacked by pridemates when she was under the influence of an immobilization drug. In each case, the attackers acted as if they no longer recognized their pridemate. According to the vets in Dallas, however, this female was in good health, though they are still running tests.

Two, when there are too many females in a confined space, they may try to reduce their group size by expelling the "excess" female. The Dallas victim had apparently been badly bitten a week or two ago—though no one knows who attacked her. It's possible that the other two females were trying to create more space for themselves and that the males picked up on the tensions within the pride. We've seen Serengeti females incite their husbands into killing females from neighboring prides.

Both of these ideas are completely speculative at this point, but it would certainly be interesting to know if the victim had CDV or epilepsy—or if there is a general problem of keeping too many females together in the small spaces of captivity. A reporter from the Dallas Morning News told me that she had heard of a second recent case of a male killing a female—in the Cheyenne Zoo. There were three females in that site, too ... Given the importance of captive breeding for these sorts of animals, it would be useful to know what caused these two deaths.

AAAS MC: You talked about having too many females in a pride, based on your time observing lions in the wild. Is there an "ideal" pride makeup and size?
Packer: It depends on the habitat: In some areas the ideal is three to 11 females, in others it's two to seven females, depending on the food supply. I don't know if anyone's ever addressed this issue in captivity—but maybe it's only two.

AAAS MC: Tell us more about the 1994 CDV outbreak in the Serengeti. Did that impact wild populations?
Packer: Yes. Take a look at this report (PDF). [Report conclusion: The 1994 CDV outbreak in the Serengeti resulted in the death of a third of the population, with high mortality rate among males.]

AAAS MC: Have there been reported cases of CDV in captive populations?
Packer: Yes, but I don't know the details.

AAAS MC: Have there been any studies that compare lion behavior in the wild versus captivity?
Packer: Not really.

AAAS MC: Captive breeding of apex predators like the lion seems highly risky. Do you think it's worth it? Is it our best chance at keeping these large mammals from going extinct?
Packer: Wild lions living in fenced reserves in Kenya, Zimbabwe, Namibia and South Africa are all doing fine [see report (Zip File)]. When reintroducing lions to depopulated areas, it is best to translocate wild lions—since they already know how to hunt and don't associate people with food. Should the Kenya, Zimbabwe, Namibia and South Africa reserves all fall into chaos, then captive lions would be the last surviving members of their kind.