Mammoth-sicle

Well-preserved frozen mammoths surface frequently from the Siberian permafrost, but the most complete so far was recently discovered by a local reindeer herder.Thanks to 10,000 years in the deep freeze, the eyes, trunk, and some hair remain intact on the six-month-old female, who perished at the end of the last ice age. Only her tail, which appears to have been bitten off, is missing. Scientists hope to carry out CAT scans of the baby's internal organs and perhaps harvest DNA from the remains.They are lucky to have found this specimen before it fell into the hands of dealers who sell mammoth parts on the black market as collectors' items; mammoth hair can go for $50 an inch.

Nocti What?

"Night-shining" clouds-mysterious wisps and slips of bright blue vapor-are appearing more frequently on the horizon just after sunset. We can only see them then because of their extreme height, which enables the sun to light them up even when it is below the horizon. But these noctilucents aren't ordinary clouds, and scientists want to know what's causing them. They develop about 56 miles up, on the edge of space, far higher than other clouds. This surprises the experts because clouds need dust and water vapor, both scarce in the upper atmosphere, as well as cold temperatures, to form.

People first noticed these clouds after the huge eruption of the volcano Krakatoa in 1883. They may have been caused by ash the volcano spewed to record heights. Today, scientists wonder whether the noctilucents are a measure of human activity. Could increasing carbon dioxide (the same stuff that causes global warming) be making the upper atmosphere colder? Is the amount of dust from meteoroids increasing as well? Is exhaust from space vehicles adding more water vapor to the upper atmosphere? Missions to study noctilucents from space aim to reveal what combination of factors-natural and human-is creating the phenomenon.

Gum Anyone?

Even cavepersons enjoyed a good chaw. At one Stone Age site in Finland, a student archaeologist recently unearthed a remarkably familiar-looking blob identified as a piece of chewed birch bark tar, complete with teeth marks. Resourceful ancient Finns used the sticky substance to fix broken clay dishes and attach arrowheads to shafts, but scientists also believe that the tar contains antiseptics that might have helped infected teeth or sore throats.The gum was made by heating birch bark and was no doubt less than "minty fresh" in taste.The search continues for the prehistoric movie theater seat to which the gum must have been attached.

Macaque Motherese

You've seen it-or maybe done it yourself. Someone arrives with an infant and everyone starts in with the baby talk. Turns out that some animals make vocal fusses over babies just as humans do. A study by researchers at the University of Chicago reveals that female rhesus macaques use a primate version of "goo goo ga ga" to engage the attention of baby macaques. Apparently, when macaque mothers and their babies hang out together, the adults speak "motherese"-but only to each others' infants, not to their own. So what are the moms saying to other monkeys' babies? Just like "goo goo" among humans, the sounds don't seem to mean anything. But they do get a baby's attention and change its mood. The researchers think this helps the mothers to bond with each other and makes the babies the focus of the group.

Me, Myself, and I

Your brain loves pronouns. Apparently, using pronouns instead of proper names helps keep the brain from becoming overloaded.

Using magnetic resonance brain imaging, psychology researchers have discovered that the brain goes berserk when it encounters, say, the name of your friend Bob as it tries to conjure up his image.When the pronoun "he" is used in reference to Bob, the brain interprets it without having to re-imagine what Bob looks like. Studying the connection between Bob and his pronoun provides researchers an excellent way to learn more about how language, especially the ability to cross-reference, works in the brain.

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