rhinoceros
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Of killer lions and lover lions
« on: 2003-02-16 18:46:18 » |
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[rhinoceros]
I found this recent article is New Scientist:
http://www.newscientist.com/news/news.jsp?id=ns99993379
Maneating lions not the walking wounded
February 12, 2003
Why do some lions become maneaters? A popular theory has it that only sick or injured lions attack humans and our livestock because they are unable to snag fleet-footed prey such as zebras and gazelles. But it turns out that most man-eating lions are young males in good physical health.
<snip>
Previously, zoologist Bruce Patterson at the Field Museum and dentist Ellis Neiburger presented evidence at a meeting of the American Society of Mammalogists that both Tsavo lions had broken teeth and jaws (New Scientist print edition, 1 July 2000). He theorised that tooth damage and dental disease - serious problems for big cats that surprise their prey and grab them by the neck - could make lions hunt for slower, less wary humans.
His findings supported those of hunter Jim Corbett, who had also noted broken teeth, missing claws and other handicaps in man-eating tigers. It was Corbett who championed the theory that injured carnivores pose the greatest danger to humans.
<snip>
With the exception of one old female that had killed and partially consumed a child, and two others euthanised for injuries caused by buffaloes, the majority of Tsavo's troublemakers were healthy males under five years of age caught on farms and ranches bordering the park.
Patterson, who is conducting several research projects on Tsavo's lions, says that young males expelled from their natural prides are leaving the park's boundaries in search of a territory and encountering a growing population of humans and livestock. It may all be too much for a young lion to resist.
[rhinoceros]
From there, I clicked on a link and found this:
http://www.newscientist.com/news/news.jsp?id=ns99992710
Lionesses go for dark, flowing manes
August 22, 2002
Male lions with long, dark manes are more attractive to females and more intimidating to rivals, US research involving dummy animals shows.
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Manes vary from light blond to black and can be up to foot long. The team planted pairs of life-sized toy lions with different types of mane near males and females in the Serengeti National Park in Tanzania, and monitored the lions reactions to the 'intruders'. In all cases, males preferred to approach dummies with lighter, less shaggy manes.
<snip>
But females did the opposite. They preferred to approach darker males, suggesting they are a better bet as a mate.
High testosterone
Next, West and Packer examined data on blood samples from several dozen males that had been sedated. They found a strong correlation between blood testosterone levels and mane colour.
"Dark colour tends to be found in high-testosterone males," West says. "Therefore, it isn't surprising that females would prefer darker manes and males would be intimidated. But there is no correlation between testosterone and mane length. We figure males are sensitive to an opponent's mane length because recently injured lions have shorter manes."
The pair also re-examined Pakcer's own research dating back to the 1960s and found evidence that dark-maned males are better able to defend their family. One-year-old cubs of darker- maned fathers are less likely to be injured and more likely to survive until they are two.
Hot-blooded
Having a large dark mane does appear to be a burden, the team point out. Dark-maned animals are hotter than blond animals, presumably because dark hairs are thicker and trap more heat, the team says.
This is important because heat hampers sperm production in the testicles. Indeed, the study re-analysis revealed a great proportion of sperm from dark-maned males are abnormal. If only the best males can afford to put up with the costs associated with it, a dark mane should be a true indicator of quality.
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