A planet full of Angelina Jolies
The female half of the species is getting more beautiful with each successive generation, while most men remain no more attractive than their cavemen ancestors, evolutionary biologists say. University of Helsinki researchers base that conclusion on a study of more than 2,000 American men and women who were tracked over decades. Women rated as beautiful had, on average, 16 percent more children than their more ordinary counterparts and more girls than boys. Handsome men, however, had no more success in reproducing than the average guy. Since men choose mates largely based on attractiveness, beautiful women have a much better chance of passing on the genes for physical beauty to the next generation of girls. Women, on the other hand, tend to choose as breeding partners men of high status and wealth, who offer protection and security for them and their children. “Historically, this has meant rich men tend to have more wives and many children,” said British psychologist Gayle Brewer. That’s true even if they look like Donald Trump or Aristotle Onassis.
Chimps aren’t immune to AIDS
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Chimps can get AIDS, too. That recent discovery, gleaned from years of observing wild chimps in Tanzania, came as a surprise, because scientists long believed that apes and monkeys didn’t get sick when they were infected with simian immunodeficiency virus, or SIV. SIV is widely found among our simian cousins in Africa, and it’s believed that after it was transmitted to humans, a genetic mutation gave rise to HIV and the global epidemic that has taken millions of lives. When field biologists in Gombe National Park carefully tracked the chimp population, they found that infected chimps died 10 to 16 times more frequently than uninfected ones, with organ and tissue damage similar to that caused by AIDS. But researchers say the chimps seem to live longer, with less damage, than untreated people with HIV. That difference, study head Beatrice Hahn tells The New York Times, “leads us to speculate that chimps may be one step ahead in adapting to the virus.” Identifying that step, she said, could lead to a more effective AIDS treatment for humans.
When your eyes are wide shut
If a scary movie soundtrack gives you the creeps, shutting your eyes will only make it worse, says New Scientist. Israeli researchers watched the brain scans of volunteers as they listened to the spooky scores from movies designed to frighten audiences. At times, the volunteers listened with their eyes open, and at other times with their eyes shut. When subjects listened to the eerie music with their eyes closed, their brain scans revealed much more activity in the amygdala and prefrontal cortex—regions of the brain that register and modulate emotion. Closing one’s eyes apparently changes how the brain perceives and processes all kinds of music, says University of Tel Aviv neuroscientist Talma Hendler, amplifying its emotional impact. “I suspect if we had music that was positive, we would get a similar effect.”
How the toucan got its bill
The toucan’s bill is the longest in the world, in some cases equaling a third of the bird’s length and half its surface area. Is it a defensive weapon, a fruit peeler, a mate attracter? Maybe it functions as all of the above, scientists say, but its primary role is to serve as a giant air conditioner. A toucan’s bill is loaded with blood vessels, which led a team of Canadian and Brazilian scientists to speculate that, like the oversize ears of rabbits and elephants, it might serve to dissipate heat. Birds, like rabbits and elephants, don’t sweat. Using heat-sensing cameras, the scientists studied toucans at different ambient temperatures. They found that when temperatures rose, more blood flowed to a toucan’s bill, which heated up while the rest of the bird stayed cool. “The animal is dumping heat, using the bill as a thermal window,” researcher Denis Andrade tells The New York Times. When it’s cold, on the other hand, the toucan can restrict blood flow into its beak, thus conserving body heat.
