Minneapolis, Minn. — Scientific breakthroughs sometimes happen like this.
Place four life-sized toy lions in Africa's Serengeti plain. Dress two of the lions with dark manes -- one long, one short. Dress the other two in blond manes -- one long, one short. Then, give the dummy lions names.
"The short black mane, he's Romeo. And the short blond mane, he's Lothario. The long blond mane, Fabio. And the long black mane had to be Julio," says lion researcher Dr. Craig Packer.
Packer has studied African lions for 20 years. The experiment to determine the purpose of the lion's mane involved placing life-sized, toy lions in the midst of real lions.
"These were toys that were custom built for us by International Bon Ton Toys of Holland. They were actually delighted to be asked to do this, because most people who make things view themselves as being basically artistic," Packer said. "And they were tired of just making stereotypical little toys of lion cubs. And when asked to make life-size replicas of real lions, they thought this was real cool. This is a real challenge."
The idea to test the length and color of a lion's mane belongs to Peyton West, a graduate student under Packer's supervision.
The real lions really were fooled by the toys -- at least for a while. But enough lions, especially females, were fooled long enough to allow Packer and West to make an important observation -- female lions preferred a male with a mane of a certain color. Length didn't matter so much as color. And black manes ruled. At least when a lioness first approached.
"She goes up and she's so excited because there's a new boy in town who is just so glamorous. And she will really disgrace herself by really coming up and inviting him to mate with her. And the dummy just stands there. The dummy is just kind of being unresponsive, and the female is really kind of like, 'Hey, this has never happened before.' And she's trying to get his attention," Packer says.
"So, the females, if they are given a choice between a blond mane or a black mane -- they like the black mane. That's sexy to them. They don't seem to care whether it's a long mane or a short mane, but it's the black that really turns them on," Packer says.
This is where Craig Packer's two decades of lion research comes in. He and West concluded lions with dark manes were healthier and stronger. In other words, they were better mates. The link is testosterone.
"And it turns out the more testosterone a male has in his blood when we sample him, the darker the mane. We also found out that these black-maned males, besides having more testosterone, also had a better ability to withstand being wounded. So that if they got bitten in a fight, they had a much better chance surviving the next year than a blond-mane male," Packer says.
"The most important thing, from the female's point of view, is that the black-maned males had babies that were better able to survive. So if a female mates with a black-maned male, she's going to have more surviving offspring, which is the real thing she gets out of this whole transaction," he says.
Dark flamboyant manes on male lions also indicate the health of the species. According to Packer, in areas of east Africa hit by global warming, the manes of lions are becoming less showy -- a marker he says, of the stress the animals are experiencing.
Artifacts of Craig Packer's and Peyton West's research, including one of the lion dummies from the Serengeti, are on display at the Bell Museum of Natural History. The exhibit, The Lion's Mane: Science in the Serengeti, runs through Nov. 28.