The best way to save Africa's lions isn't limiting the number killed by hunters, conservation biologists now say. Rather, it's making sure only older males get shot. But how can a hunter tell the age of a big cat lined up in the crosshairs? By knowing noses, according to new research.
Ironically, the survival of lion populations outside Africa's national parks may depend in part on hunters. Money from trophy hunters gives local people an incentive to maintain lion populations on privately owned or leased game reserves. However, killing a dominant male has dire consequences. When other males take over the pride, they kill the cubs, so they can more quickly sire their own offspring. Trophy hunting makes such violent takeovers more frequent.
Allowing hunters to take only older males would help counteract the effects of infanticide, according to a team led by Craig Packer and graduate student Karyl Whitman of the University of Minnesota, Twin Cities. The team's computer simulations showed that when hunting was allowed for males as young as 3 or 4, populations declined as did the number of trophy males hunters could harvest. However, both lion populations and numbers of trophy animals were sustained when hunting was allowed only for males aged 5 and up, the team reports online 22 February in Nature. Shifting hunting pressure to older males allowed males just coming into their prime adequate time to raise one or more sets of cubs, the researchers explain.
This policy creates a win-win situation for both conservationists and hunters, the researchers say. And because lions' noses become darker as they age, nose color could serve as a handy gauge of age. Professional guides with binoculars and riflescopes should be able to detect nose color, they say.
This approach is a practical way to make hunting sustainable, says wildlife biologist Jon Swenson of the Agricultural University of Norway in Ås. "For conservation purposes, it's just superb." Wildlife biologist Tim Caro of the University of California, Davis, likewise applauds the quality of the science, but worries that hunters would not abide by a policy based on nose color, especially because much hunting occurs at night and hunters pay huge sums of money for precious few chances to bag a lion.