"We were initially very skeptical of our result because we expected mane length to be the most important consideration," said West. "It is well-known that a short, scruffy mane is the sign of a sick male."
Badge of Health
But color seemed to be the critical factor.
Together with other biochemical and photographic data acquired over the years by West's advisor, Craig Packer, West suggested that the dark mane may in fact be a sign of a stronger, fitter male.
An analysis of photos of 313 adult males taken between between 1964 and 2000, disease surveillance data, blood samples, and nutritional statusgauged by the belly sizerevealed that longer, darker manes were associated with age, better health, and higher testosterone levels.
"I think this is a great paper with a very interesting hypothesis. The lion and its mane has fascinated people since early times, yet nobody has ever shown any data on its purpose," said Göran Spong, an evolutionary biologist at the University of Uppsala in Sweden, who has studied lion population genetics and social evolution. "Most people, including myself, have assumed it is for protection rather than for show."
It has been widely observed that mane color and length is affected by climate. In cooler regions like Morocco and South Africa's Cape region, lions have darker, thicker manes. In Kenya's Tsavo National Park, the climate is considerably hotter and the lions are almost maneless. Having a thick, dark mane comes at a costheat stress.
"Males with darker manes were hotter than those with lighter manes," said West. West used a thermal-imaging camera to measure the surface temperatures of lions in the Serengeti, Ngorongoro Crater, and Tsavo. West says only superior males can afford the costs of a large, dark mane.
West and Packer's results suggest that the features that intimidate other males are the very factors that the females are looking for, said West.
For females, a stronger male can better defend his pride against intruding males and produce stronger offspring.
"I remain unconvinced it is simply a badge of health," said Spong. "Females may simply use an easily assessed indicator of male quality which is really there for a different purpose." Spong said that he doesn't believe that females have a lot of choice when it comes to finding a mate.
"Males forcefully enter prides; they often kill resident cubs. Females must make the best of a bad situation and thus after a few months will conceive with the new males. To me, this doesn't sound like the setting where females can go around being choosy."
While the exact purpose of the manewhether a shield of protection, or a badge of healthmay still be up for debate, it still stands that gentlemen prefer blondes and ladies want their mates tall, dark, and handsome.
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