Blue Whale Song Mystery Baffles Scientists

All around the world, blue whales aren’t singing like they used to, and scientists have no idea why. The largest animals on Earth are singing in ever-deeper voices every year. Among the suggested explanations are ocean noise pollution, changing population dynamics and new mating strategies. But none of them is entirely convincing.

Scientists first noticed the change eight years ago, when they kept needing to recalibrate the automated song detectors used to track blue whales off the California coast. The detectors are triggered by songs that match a particular waveform. Their analysis shows that the songs’ tonal frequency is falling every year by a few fractions of a hertz. There seem to distinct populations of whales in different oceans, yet they’re all showing this common shift.
Because only male blue whales sing, the answer may involve mate choice and sexual selection. The researchers hypothesize that as larger, ostensibly more virile whales tend to produce deeper songs, other males may be trying to emulate them, just as human guys might lower their voices when trying to impress a woman.

Scientists note that whale songs are a cultural affair. Humpback whales are known to learn from each other, and whales have extraordinarily large and complex brains. They appear to share many social and cognitive traits with people.

Read more at the original article here.

Raptor Talons

The pictures below are from a recent study on raptor talons. For a summary of the findings, read the article here. The talons below are from the following: (A) goshawk (B) red-tailed hawk (C) peregrine falcon (D) great grey owl (E) osprey.

Puppy vs. Praying Mantis: Who Wins this Smackdown?

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Turtle Completes the Impossible

World's Weirdest Worms

Five years after discovering some of the strangest creatures in the world — mouthless worms that live in the bones of dead whales — scientists have taken a peek into their genes. Though not complete, the glimpse shows these creatures to be far more complicated than was known.

The worms, found in a gray whale skeleton off the coast of California, prompted scientists to designate them as representatives of an entirely new genus, dubbed Osedax. They belonged to a taxonomic family of marine worms that lack mouths and anuses, and rely entirely on bacteria to absorb and excrete nutrients. But Osedax was unique: Adult males were extremely small, and lived in colonies inside the females. Even more strikingly, they occupied an evolutionary niche comprised entirely of fallen whales.

Scientists note that anything below 1000 meters is fed entirely by ‘marine snow’ — the things that are supported by photosynthesis at the top of the ocean, and the things that eat them, and eventually fall to the ocean floor.

Since the original discovery, other species have been found in whalebones off the coast of Sweden and Japan. A total of five species have now been named, enough for a comparison of their genetic characteristics to provide insight into their evolutionary history. The analysis suggested at least 12 more as-yet-unidentified lineages of Osedax. The worms might still be out there, though some may have gone extinct.

Since whale carcasses are hard to come by, researches have been able to study the worms by luring them with carcasses of other animals. They can live perfectly happily on cow bones, and researchers have also put down sea lion bones and pig bones.

You can see an ocean-floor webcam here, where researchers recently sank a pig.

Original article here.

Birds Use Light, Not Magnetic Field, to Migrate

In European robins, a visual center in the brain and light-sensing cells in the eye — not magnetic sensing cells in the beak — allow the songbirds to sense which direction is north and migrate correctly, according to a new study in Nature. The study may improve conservation efforts for migratory birds.

Researchers have known that built-in biological compasses tell migrating birds which way to fly, but the details of how birds detect magnetic fields has been unclear.

Some researchers had proposed that iron-based receptors in cells found in the upper beaks of some migratory birds sense the magnetic field and send that information along a nerve to the brain. Other scientists favor the hypothesis that light-sensing cells in birds’ eyes sense the magnetic field and send the information along a different route to a light-processing part of the brain called cluster N.

To find the location that houses the magnetic compass, scientists caught 36 migratory European robins and made sure that the birds could all orient correctly under natural and induced magnetic fields. Next, the researchers performed surgeries on the birds to deactivate one of the two systems. The team either severed the nerve that connects the beak cells to the brain, or damaged the brain cells in cluster N that receive light signals from cells in the eye.

Birds with the severed beak-to-brain nerve — called the trigeminal nerve — still oriented perfectly, suggesting that the beak cells are not important for orientation. On the other hand, birds with damaged cluster N regions could no longer sense and orient to magnetic fields. These robins failed to pick up both the Earth’s natural magnetic field and the artificial fields created by the researchers.

Understanding more about how birds navigate and sense the environment may have important conservation implications. Migratory birds that humans have relocated often fly back to the original migratory grounds. But if researchers can figure out how the birds navigate, conservationists may be able to trick the birds into staying where it’s safe.

Original article here.

The Spider Awards: Arachnid Hall of Fame

Below are several examples of spiders from Wired's Spider Awards: Arachnid Hall of Fame. Read the article to learn more about the various species. Example "awards" for spiders include: largest, smallest, deadliest, cutest, nicest, sneakiest, weirdest, snobbiest, cuddliest and busiest.



















Original article here.

Stem Cells from Fat Used to Grow Teen's Missing Facial Bones

Surgeons have reported success in first human bone growth procedure using fat stem cells.

Stem cells so far have been used to mend tissues ranging from damaged hearts to collapsed tracheas. Now the multifaceted cells have proved successful at regrowing bone in humans. In the first procedure of its kind, doctors replaced a 14-year-old boy's missing cheekbones—in part by repurposing stem cells from his own body.

The technique, should it be approved for widespread use, could benefit some seven million people in the U.S. who need more bone—everyone from cancer patients to injured war veterans.

Read more in the original article here.

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Fossils Push Back Earliest Complex Animals 40 Million Years

A series of fossils unearthed in southwestern China has revealed the origins of complex life in unprecedented detail, and pushed its beginning back by at least 40 million years.

The specimens come from the Doushantuo formation, a layer of sediments deposited about 590 million years ago, just before the Ediacaran period’s primordial fauna gave way to the complex creatures of the Cambrian explosion.

During the Ediacaran, even the most structurally complicated animals had flat bodies with simple symmetry, like living quilts or mattresses. It was only during the Cambrian that animals developed what’s known as bilateral symmetry — a distinct front and back, top and bottom.

The Doushantuo fossils date to the cusp of this transition, and are so finely preserved that scientists can distinguish the structures of individual cells. The latest fossils aren’t even fully formed animals, but embryos.

Using synchrotron radiation microtomography — a microscopy technique that combines thousands of of X-rays taken from different angles — researchers reconstructed the embryos in three-dimensional detail. They found that the embryos were bilaterally symmetrical, and were organized so differently that they belonged to two distinct taxonomic groups. For those groups to be so different, bilateral symmetry must have been around for a while.

Original article here.

Giant Orb Spider Discovered

Scientists have found the world’s largest species of golden orb-weaver spider in the tropics of Africa and Madagascar. The discovery marks the first identification of a new Nephila spider since 1879.

Females of the new species, Nephila komaci, measure 4 to 5 inches in diameter, while the male spiders stay petite at less than a quarter of their mate’s size. So far, only a handful of these enormous arachnids have been found in the world. Its only definite habitat is a sand forest in Tembe Elephant Park in KwaZulu-Natal.

Like all Nephila spiders, females of the new species spin huge webs of golden silk, often more than 3 feet in diameter. In the report of the discovery of this rare spider, the researchers also addressed the evolution of the dramatic size difference between male and female orb-weavers.

By mapping out the evolutionary tree of all known orb-weaver species, the scientists discovered that as the spiders evolved, females got bigger and bigger, while males stayed roughly the same size.

It is good for females to be big, because they can lay so many more eggs. In addition, large size probably helps females avoid being eaten by predators. Males, on the other hand, are better off staying small and reaching sexual maturity at a young age. Because males spend most of their time underground, hunting for a mate is one of the most dangerous activities they undertake.

Original article here.