Health & Science

The chimp who plans for the future

Human beings can imagine and plan for future events—a capability that scientists have long believed makes us unique among living creatures. But an angry chimpanzee in a Swedish zoo has shown that his species is capable of meticulous preparations for the future: He stockpiles rocks, shapes them into aerodynamic discs, and then waits hours for zoo visitors to come into range so he can pelt them. The chimp, named Santino, began hurling rocks at people 11 years ago, when he was 19—a time when male chimps become aggressive and try to establish dominance. Every morning before visitors start to trickle in, Santino roams his outdoor enclosure, searching for small stones. He’s learned to make his own stones, too, by knocking pieces off the concrete walls. At times, Santino shapes his weapons into discs, so they sail through the air more accurately. The chimp stacks the stones in small piles, so that when he becomes irritated by visitors invading his territory, he has an ammunition store on hand and can begin hurling his missiles. No one has been hurt (chimps have lousy aim), but it’s an impressive performance nonetheless. In the wild, chimps use tools, but to address immediate needs, not future ones. Santino’s behavior, Swedish primatologist Mathias Osvath tells the Associated Press, “convincingly shows that our fellow apes do consider the future in a very complex way. It is very special that he first realizes that he can make these [stone missiles] and then plans on how to use them.”

Why women have orgasms

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The female orgasm isn’t just for fun, says LiveScience.com. When a women has an orgasm, research by biologists Robin Baker and Mark Bellis has found, her uterus and vagina contract in rhythm—a “welcome dance” that creates a vacuum and pulls extra sperm into the uterus. Since the reproductive tract normally retains only about 65 percent of the semen it takes in, this suction provides an extra boost, giving sperm a better chance of reaching the egg. Female orgasm, Elad believes, has evolved to act as a preference mechanism in a world in which women may have multiple sexual partners. When a woman prefers one man to others, her body can give his sperm an advantage over its rivals, increasing the likelihood that she’ll conceive with the most attractive, attentive partner.

Bad weather, bad headaches

For chronic headache sufferers, heat waves and thunderstorms aren’t just an inconvenience. Rising temperatures and falling barometric pressure, says a new study, often portend a pounding headache for those prone to them. A survey of 7,000 patients whose headaches were bad enough to prompt a visit to the emergency room revealed that for each 9-degree increase in temperature, the chance of an attack in the following few days increased by 7.5 percent. Low barometric pressure readings—which usually accompany storms—were also linked with increased risk. “I wish I knew why this happens,” study author Kenneth Mukamal tells Discovery.com. “It clearly affects your internal circuitry.” Doctors who treat people who suffer migraines and other chronic headaches say 50 percent of their patients have reported suffering terrible episodes when the weather becomes extreme.

Can swimming make you fat?

If you exercise to lose weight, chose your sport carefully. New research shows that certain forms of exercise cause people to feel more hungry than usual—with the result that calories burned off are quickly replaced. Swimming in cold water, the study by Loughborough University in the U.K. found, tends to make people crave high-fat foods, while mid- to low-intensity exercise such as walking has no impact on appetite. Running on a hot day, on the other hand, actually suppresses appetite. Different forms of exercise apparently have different impacts on production of the appetite hormone ghrelin. “The body tends to respond to exercise so that it can do it more efficiently in the future,” explains researcher Dr. David Stensel. Runners perform better if they have low body weight, he says, while cold-water swimmers benefit from protective fat.

Why men don’t notice haircuts

A woman spends $300 getting her hair cut and highlighted. She comes home, waiting anxiously for her husband’s reaction—but he says nothing. It might not be because he’s a jerk, says New Scientist; he simply may be suffering from “hair blindness.” Cognitive neuroscientist Brad Duchaine, who works with prosopagnosiacs—people who can’t recognize faces—has found that the brain generally does not recognize hair as a facial feature, like it does eyes and noses. Prosopagnosiacs, in fact, often make up for their deficit by identifying people by their hairdos. “Normal” men, Duchaine believes, focus mainly on their spouse’s or girlfriend’s face upon greeting them, and therefore may not really “see” that their hair has changed.