The number of traits chalked up as “distinctly human” seem to dwindle each year. And now, we can’t even say that we’re uniquely aware of the limits of our knowledge: It seems that some monkeys understand uncertainty too.

A team of researchers taught macaques how to maneuver a joystick to indicate whether the pixel density on a screen was sparse or dense. Given a pixel scenario, the monkeys would maneuver a joystick to a letter S (for sparse) or D (for dense). They were given a treat when they selected the correct answer, but when they were wrong, the game paused for a couple seconds. A third possible answer, though, allowed the monkeys to select a question mark, and thereby forgo the pause (and potentially get more treats).

And as John David Smith, a researcher at SUNY Buffalo, and Michael Beran, a researcher at Georgia State University, announced at the AAAS meeting this weekend, the macaques selected the question mark just as humans do when they encounter a mind-stumping question. As Smith told the BBC, “Monkeys apparently appreciate when they are likely to make an error…. They seem to know when they don’t know.”

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Beauty doesn’t only fade within a lifetime–it also fades genetically over the course of several generations, according to new research. Scientists studying populations of sexually attractive male fruit flies have found that there’s a limit to their evolutionary success–and that there may actually be a disadvantage to being too sexy.

For the study, published in the Proceedings of the National Academy of Sciences, researchers genetically modified male fruit flies, causing them to give off excessive amounts of attractive pheromones. The scientists then introduced a flock of these foxy fellows to a normal fruit fly population. They discovered that the female flies mated with these modified flies more often initially, and the proportion of super-sexy males increased for a while–but the proportions returned to normal after seven generations.

As The New York Times reports:

“Even though we were able to make males more attractive, there must have been a fitness cost,” said Katrina McGuigan, a biologist at the University of Queensland and one of the study’s authors. “While sexual selection is really powerful, there are consequences to nonsexual traits.”

It’s not yet clear what genetic disadvantage these fruit fly ladykillers may have had. But let’s turn to the more urgent question: Is there any carryover implications for humans? The New York Times quotes McGuigan:

“Hard to say, but only that very attractive individuals may well have something wrong with them — they may not be as good as they seem to be at first glance.”

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Image: Wikimedia Commons / A. O’Toole

It’s furry like a mouse but sings like a bird. What is it? It’s a mutant mouse developed by the genetic engineers at the University of Osaka that is able to tweet and chip like a bird, instead of a mouse’s normal squeak.

Like dog breeders, who actively select for certain traits (like size, hair color, or disposition) the researchers from the Evolved Mouse Project crossbred their mutant mice to select for various traits. When they find one they like, like this singing mouse or the one that looks like a miniature Dachshund, they breed them until they have a sizable breeding stock of animals to establish a new breed.

The research group currently has over a hundred singing mice (it must get noisy in those labs) and they are continuing to study how they use their chirps, researcher Arikuni Uchimura told the AFP:

“Mice are better than birds to study because they are mammals and much closer to humans in their brain structures and other biological aspects,” Uchimura said. “We are watching how a mouse that emits new sounds would affect ordinary mice in the same group… in other words if it has social connotations.”

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While watching the science news for you here at Discover blogs, we’ve seen our share of bad science coverage. Most of the time, we let it slide. Most of the time, we write the truth and hope to overshadow the erroneous and exaggerated stories. But this time… this time we’re calling it out.

Last week’s coverage of the bacteria that live in Mono Lake, CA was over hyped because of a cryptic message in a NASA press release (namely, that the discovery would “impact the search for evidence of extraterrestrial life”). And even after all the build up, the early embargo break, and a long press conference, many news outlets STILL got the story wrong.

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Have a brain for puzzles? What about ones that help advance science?

A new online game called Phylo is harnessing the power of idle brains on the Internet–asking any and all to help align genomic sequences. Human brain power is used instead of computer power because, as the researchers explain in the press release, humans are still better at some things than computers are:

“There are some calculations that the human brain does more efficiently than any computer can, such as recognizing a face,” explained lead researcher Dr. Jérôme Waldispuhl of the School of Computer Science. “Recognizing and sorting the patterns in the human genetic code falls in that category. Our new online game enables players to have fun while contributing to genetic research–players can even choose which genetic disease they want to help decode.”

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Earlier this week Richard H. Thaler posted a question to selected Edge contributors, asking them for their favorite examples of wrong scientific theories that were held for long periods of time. You know, little ideas like “the earth is flat.”

The contributor’s responses came from all different fields and thought processes, but there were a few recurring themes. One of the biggest hits was the theory that ulcers were caused by stress—this was discredited by Barry Marshall and Robin Warren, who proved that the bacteria H. pylori bring on the ulcers. Gregory Cochran explains:

One favorite is helicobacter pylori as the main cause of stomach ulcers. This was repeatedly discovered and then ignored and forgotten: doctors preferred ‘stress’ as the the cause, not least because it was undefinable. Medicine is particularly prone to such shared mistakes. I would say this is the case because human biology is complex, experiments are not always permitted, and MDs are not trained to be puzzle-solvers—instead, to follow authority.

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Apple may not allow porn on its product line, but it has no problem with another source of controversy: evolution. A new, free iPad/iPhone application called Timetree, distributed by Arizona and Penn State Universities, allows users to map how long ago two living creatures separated on the tree of life, a subject that can get a bit sticky with creationists, says The Register:

Now, Apple has taken a stance which will upset a lot of Americans: it has allowed an app which specifies quite clearly that evolution is real and that humans and monkeys share a common ancestor some 30 million years in the past.

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Any culture’s religious ceremonies can seem strange to outsiders: For example, take the indigenous Zoque people of southern Mexico. To ask their gods for bountiful rains during the growing season they head to a sulfur cave where molly fish swim in the subterranean lake. They then toss in leaf bundles that contain a paste made from the mashed-up root of the Barbasco plant, which has a powerful anesthetic effect.

When the stunned fish–which the Zoque people consider a gift from underworld gods–go belly-up, people scoop them from the water and bring them home for supper. This fishy protein helps them make it through until the harvest.

This ritual came to the attention of scientists studying the molly fish, who wondered how the toxic root might be affecting fish populations in the caves. So evolutionary ecologist Michael Tobler and his colleagues did a little field research.

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The rats scuttling around the tracks of the New York City subway pale in comparison to a gargantuan species recently discovered in East Indonesia. In fact, the recently discovered rat tipped the scales at a somewhat frightening 13 pounds. That’s sizably heftier than today’s house rat (which averages 5 ounces) and burliest wild rats (which weigh about four-and-a-half pounds). This mega-rat lived in Timor until it went extinct between 1,000 and 2,000 years ago. It was one of 11 new species discovered at the excavation site–eight of which weighed more than two pounds, and only one of which survives today.

But the now-extinct rats didn’t die off until well after humans first arrived, according to LiveScience:

“People have lived on the island of Timor for over 40,000 years and hunted and ate rats throughout this period, yet extinctions did not occur until quite recently,” said study researcher Ken Aplin… adding that the arrival of humans to an area doesn’t necessarily have to equate with extinctions… “Large-scale clearing of forest for agriculture probably caused the extinctions, and this may have only been possible following the introduction of metal tools.”

East Indonesia is a hotspot for rat evolution, with unique species found on each island, and the possibility of finding more.

“Although less than 15 percent of Timor’s original forest cover remains, parts of the island are still heavily forested, so who knows what might be out there?” [researcher] Aplin said.

Which is fine with us–as long as they stay far, far away from our homes.

Related content:
Discoblog: Weird Science Roundup: Super-Rats, Heart-Attack Virus, and the Real Breakfast of Champions
Magazine: English Super-Rats
Magazine: A-maze-ing Mole Rats

Image: flickr / korobukkuru

It’s pretty clear that–in a fight–Darth Vader would crush Jar Jar Binks, Optimus Prime would beat Starscream, and Batman could pummel the Joker. Though some of these fictional characters don’t even look like humans, when it comes to strength, their voices give it all away. New research seems to confirm this: humans, like other animals, can accurately predict physical strength from voice alone.

In a study appearing today in The Proceedings of the Royal Society, researchers asked subjects to evaluate the upper-body strength of speakers from four distinct populations and language groups just by listening to their voices. Even when unfamiliar with a speaker’s language, listeners could tell which men might be good in a fight. The men they judged as sounding brawny were in fact physically stronger as measured by tests of hand grip, chest strength, shoulder strength, and bicep circumference.

As lead author Aaron Sell told Discovery News:

“Information about male formidability would have been important for both sexes over evolutionary time,” said Sell. “Both men and women would have benefitted from knowing who would likely win fights in order to make prudential alliances and for other reasons. Men would need this information to regulate their own fighting behavior. Women would also need this information in order to make effective mate choices.”

They study failed to make a similar link between women’s voices and strength. The study’s authors speculate that this is because early men were more likely to spar. The researchers also couldn’t determine what it was about certain male voices that made them sound strong–it wasn’t just a deep timbre–and say listeners may respond to a complex mix of cues.

For men, the finding proves especially interesting given the non-menacing statement researchers asked English speakers to say: “When the sunlight strikes raindrops in the air, they act like a prism and form a rainbow.” Apparently this sentence is from a passage that contains almost all the sounds of the English language, but those certainly aren’t fighting words.

Related content:
Discoblog: Speaking French? Your Computer Can Tell
Discoblog: Penn State’s Football Stadium: Now 50% Louder!
Discoblog: NCBI ROFL: Did Gollum have schizophrenia or multiple personality disorder?

Image: flickr / ~ggvic~