It turns out the search for a tall, dark, and handsome mate isn’t limited to dating websites—or even to humans. A lion’s mane will change color in accordance with its nutrition level and overall well-being; a male lion with a darker mane tends to be healthier and have higher testosterone levels. As a result, lionesses find lions with darker manes more attractive, according to biologist and National Geographic grantee Craig Packer.In one study, a graduate student working with Packer used stuffed toy lions with various mane colors to test female preference. That study found that 90 percent of the time lionesses chose to approach the replicas with darker manes. Nature is so typical—boring, good-looking dudes ruining it for the rest of us. Maybe the remaining 10 percent of lionesses are more interested in a potential mate’s personality qualities? In this week’s " Today I Learned ," Packer explains a bit more about this phenomenon.