Men Can't Help It, Mammoths and More

Here is a quick selection of stories that caught my eye.

Here is more proof that women are just trouble. ;)

Men Pay the Ultimate Price to Attract Women

While it is tough to be a woman, being a man can be downright deadly.

Women live longer than men. And now scientists suggest a simple Darwinian reason: Competing for a mate can wear a guy out or get him killed.

"Women live longer in almost every country, and the sex difference in lifespan has been recognized since at least the mid-18th century," said Daniel Kruger at the University of Michigan. "It isn't a recent trend; it originates from our deep evolutionary history."

The idea is presented in the spring edition of the journal Human Nature.

Butting heads

In common chimpanzees, Kruger and his colleague Randolph Nesse report, mortality spikes among males around age 13, just as they're old enough to breed and start competing for social status.

Males of many species must fight vigorously for the right to mate. Think of rams butting heads. Spectacular male bird plumage is another example of biological effort required to succeed, effort that uses energy and can shorten a life.

In this scheme of natural selection, evolution shapes traits that help the best genes survive, sometimes to the detriment of individuals.

Human males don't always have to wrestle to get a woman these days, but the pressure to succeed sexually hasn't changed much, the researchers argue. Only the methods have been revised.

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Fatherhood at First Sight: Women Can Spot Good Dads By Their Faces

CHICAGO (AP) -- Women looking for a long-term relationship like men who like children -- and they can tell which guys might be interested in becoming fathers just by looking at their faces. Those are among the findings of a study of college students published Wednesday in a British scientific journal.

"This study suggests that women are picking up on facial cues that are perhaps related to paternal qualities,'' said James Roney, a University of California at Santa Barbara psychologist and lead author of the study. "The more they perceived the men as liking kids, the more likely they could see having a longer-term relationship.''

Experts said evolution has apparently programmed women to recognize men who might be interested in propagating the species by raising a family.

The study wasn't all bad news for men not interested in settling down. It found that women can look at men's faces and figure out which of them have the highest testosterone levels. Those men -- rated the most masculine by the women -- turn out to be just the kind of guys they would want for a fling.

"Women make very good use of any information they get from a man's face,'' said co-author Dario Maestripieri, an associate professor of comparative human development at the University of Chicago. "Depending on what they want and where they are in their lives, they use this information differently.''

Click here for the full story.

Maybe this old mug isn't so bad after all. Rounding out the current selection I bring you the following ditty.

Climate Change, Not Humans, Killed Large Beasts

"Failure to adapt to a drastically changing climate, and not overkill by humans or disease, most likely lead to the extinction of mammoths, wild horses, and other large mammals after the last Ice Age, a new study suggests.

But this fresh take on an old argument might not be the final word.

Dale Guthrie of the University of Alaska has added 600 radiocarbon-dated fossils to the established collection, and his examination reveals that mammoths and wild horses were in serious decline before humans arrived on the scene in Alaska and the Yukon Territory.

Like the end of the dinosaurs, the topic of large mammal extinctions is a hot one. While the new results might be true of the far North, some researchers still believe over-hunting contributed to the demise of the beasts across the rest of the continent.

The study, which also analyzed the fossil record of bison, elk, moose, and humans in the far North between 18,000 and 9,000 years ago, is published in the May 11th issue of the journal Nature.

Pushed to the brink

It's generally accepted that humans first entered North America from Siberia around 12,000 years ago. Since mammoths and wild horses became extinct roughly 11,500 and 12,500 years ago, some scientists have figured that hungry humans might have hunted them into oblivion.

"The old idea, that I once had, was that these animals were killed off and then the modern large mammals expanded and took their place," Guthrie said.

According to Guthrie's new data, however, bison and elk populations were doing well during this period, and those species had expanded dramatically long before other species went extinct. So why weren't bison and elk over-hunted to extinction as well? Interestingly, the fossil record shows the two beasts were hunted more vigorously, yet they endured.

"I imagine humans were hunting anything they could get," Guthrie said. "Horse meat is probably just as tasty as bison. But their campsites don’t show many mammoth and horse remains—they're full of bison and elk."

Guthrie's interpretation of the fossil record is that something else pushed mammoths and horses to the brink, and if humans did play a role in the extinctions, it was limited to just killing stragglers.

The fossil record also casts doubt on the possibility of a mega-disease that wiped out animals across the board, Guthrie said. A deadly disease would create a distinct end for each species, which isn't reflected in the fossils. Also, diseases that infect and kill multiple species are extremely rare, and unlikely in this case since bison, elk, and moose weren't affected.

So what happened up North?

The period between 13,000 and 11,000 years ago was a great transitional time for the far North. Although scientists don't know exactly what happened during this period, they can tell certain things from the geologic and fossil record."

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