What’s the News: Most poisonous snakes don’t inject their prey with venom; instead, they bite the prey and venom insidiously trickles down a groove on their fangs into the wound. A new study in Physical Review Letters investigated the physics behind how venom travels down the grooves: It turns out that snake venom has unusual viscosity properties that keep it cohering together until it’s time to flow down the fangs and into the snake’s soon-to-be-snack—the same properties that account for how ketchup seems stuck in the bottle, then flows freely onto your fries.

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Ask a group of snake researchers whether our modern snakes evolved from land-loving or ocean-loving lizards, and you’re likely to start a heated argument. But the days of snake-origin squabbles may be coming to a close–researchers have created the first 3-D images of snake fossils and have discovered that their legs are more akin to the legs of land-dwelling lizards than they are to the ocean-dwelling kind.

The researchers studied a 95-million-year-old fossilized snake called Eupodophis descouensi that was found in present-day Lebanon. Published in the Journal of Vertebrate Paleontology, the scientists used a novel 3-D imaging technique called synchrotron-radiation computed laminography:

“Synchrotrons are enormous machines and allow us to see microscopic details in fossils invisible to any other techniques without damage to these invaluable specimens,” said co-author Paul Tafforeau from the European Synchrotron Radiation Facility. [Discovery News]

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They may not be as adorable as sugar gliders, but they’re just as accomplished: Five species of Asian snake have also developed the ability to “fly” or glide from tree to tree, flattening out their bodies to travel up to 80 feet.

Researcher Jake Socha and his team studied the glide of Chrysopelea paradisi snake and took videos of the snakes in flight, which Socha presented at an ongoing meeting of the American Physical Society. He found that before a snake takes the leap it curls its body into a J-shape, and then launches itself from the tree branch. In the air, it flattens its body and undulates, as if slithering through the air.

The snake differs from other gliding species, like gliding lizards and flying squirrels, in that it doesn’t have specialized body parts that act as wings.

“The whole snake itself is just one long wing,” Socha said. “That wing is constantly reconfiguring, it’s constantly reforming and contorting.” [LiveScience]

Hit the jump for a video of the snake in action.
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A tiny fraction of vertebrate species have ever been seen reproducing through parthenogenesis, the fatherless birth of offspring in which the embryo develops without fertilization by a male. Now you can add boa constrictors to that short list: A study in Biology Letters documents the case of a boa that gave birth to 22 offspring over the last two years, all of whom are female and born this unusual way.

“Only with the development and application of molecular tools have we truly begun to understand how common this form of reproduction may be,” lead author Warren Booth [says]. Booth, a research associate at North Carolina State University’s Department of Entomology, and his team first suspected something was up when the mother boa constrictor gave birth, twice, to a total of 22 caramel-colored females. The males housed with the female did not carry the gene for this recessive color trait. [Discovery News]

When Booth’s team analyzed the DNA of the young snakes, they found no evidence of paternity by any of the males who’d mated with their mother previously. Furthermore, the chromosomes of the 22 young gave them away.

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The turn of the millennium was not kind to the snakes.

Herpetologist Chris Reading and his team have been counting snakes through their own surveys and looking at population data going back to 1987 to see what’s happening to snake populations. The alarming findings, to be published soon in Biology Letters, indicate that most of the species studied saw a great decrease in population, with the greatest loss between 1998 and 2002.

Reading’s team monitored 17 different species in different climates—including snakes from Europe, Africa, and Australia—to try to get a global picture. Eleven of the 17 declined sharply over the study’s two-decade-plus period, with some declining as much as 90 percent. Five remained more or less stable. Only one saw a population increase, and a very slight one at that.

“All the declines occurred during the same relatively short period of time and over a wide geographical area that included temperate, Mediterranean and tropical climates,” write the authors. “We suggest that, for these reasons alone, there is likely to be a common cause at the root of the declines and that this indicates a more widespread phenomenon” [Guardian].

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Some of the weird wildlife on Madagascar—its mammals especially—probably arrived there by rafting from mainland Africa, we reported back in January. But not its blind snakes. According to a study out now in Biology Letters, these funny-looking creatures date back 150 million years to the Gondwana landmass, and have lived on Madagascar since before it broke off from India and drifted away. And, the researchers say, their story of spreading around the world carries many more twists.

Growing to about a foot long, blind snakes act a lot like worms, burrowing under the surface of every continent except Antarctica. Unlike worms, though, blind snakes have backbones and tiny scales [National Geographic]. They earned their moniker by having blurry vision and sensing chemicals through their skin to find their way around. But despite having backbones, there are few blind snakes in the fossil record, making it hard for researchers to study their evolutionary history. So lead researchers Blair Hedges and Nicolas Vidal had to rely on living species. They extracted five nuclear genes, which code for proteins, from 96 different species of worm-like snakes to reconstruct the branching pattern of their evolution, allowing the team to estimate the times of divergence of different lineages using molecular clocks [UPI].

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Take a good look: according to a new study in PLoS Biology, what you see in this image is a snake about to prey on dinosaur eggs, a 67-million-year-old scene frozen in time and finally discovered. It’s the first time that a snake has been seen eating a dinosaur. The snake is that bit of bones on the left, lead researcher Jeff Wilson says. The egg in the top right contains a tiny titanosaur, one of largest dinosaur groups to ever walk the Earth.

“The snake (Sanajeh indicus) probably lived around the nesting ground and preyed upon hatchlings. They all died instantly when they were covered by a big pulse of sediment from a nearby hill loosened by a storm,” says Wilson [New Scientist]. Wilson guesses that a storm or some other malady might have led the enormous adult dinos to leave the nest, opening the door for the snake to slither in, wait for the baby dinos to hatch, and snack on them. But it never got the chance.

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This week federal officials said they want to ban the importation of nine large and exotic snake species. The move is designed to quell the spread of those slithering reptiles that have gotten loose and thrived in Florida and especially in the Everglades, and that threaten to spread further across the country.

More than a million of these snakes—including the giant Burmese python, boa constrictors, and several kinds of anaconda—have come to the United States in the last 30 years as pets. But invariably, over the years, some slithered loose — or were released by owners who found their reptile[s] more than they could handle. Today, many thousands nest wild in Florida’s suburban yards, parks and the Everglades [Science News]. At least one of the species, the northern African rock python, is considered dangerous to humans.

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Earlier this month DISCOVER covered the 213-million-year-old fossils of the theropod Tawa hallae, a dinosaur ancestor that could show how early dinos spread around the world. Now, in a study (in press) in the Proceedings of the National Academy of Sciences, another research team has uncovered a surprise in the bones of a theropod from almost 100 million years later. By that time, these creatures may have adopted a clever new weapon: venom.

Sinornithosaurus lived 125 million years ago in what’s now China, and while it might have been covered in feathers (and the size of a turkey), the researchers say it attacked like modern rear-fanged snakes. Rear-fanged snakes don’t inject venom. Instead, the toxin flows down a telltale groove in a fang’s surface and into the bite wound, inducing a state of shock [National Geographic].

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What’s worse than having one gigantic-but-relatively-docile python species invading Florida? Finding out that an extremely aggressive python species is moving in as well, and learning that the two species could theoretically interbreed to create a hybrid monster.

Florida wildlife officials have been concerned for some time about the 20-foot-long Burmese pythons that are thought to have been released by irresponsible pet owners and have established a thriving colony in Everglades National Park. But over the past year, four African rock pythons have also been sighted or captured in Miami-Dade county, giving biologists new cause for concern. Says herpetologist Kenneth Krysko: “They are just mean, vicious snakes…. You couldn’t get a worse python to become established. A Burmese python is just a docile snake. These things will lunge at you” [Miami Herald].

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Scientists have discovered a clever way the yellow-lipped sea krait snakes deter predators: By making it look as though the venomous snake has two heads, according to a study published in the journal Marine Ecology.

A biologist first noticed the snakes’ tricky method while diving in Indonesia. Researcher Arne Rasmussen observed the animals foraging for food while simultaneously moving what appeared to be a bobbing head around–but that bobbing body part was really its tail. “[T]he tail was slowly writhing back and forth, much in the same way as the head moves on a vigilant and actively searching snake” [National Geographic News], said co-author Johan Elmberg, who did not see the snake, but teamed up for the study with Rasmussen.

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The burgeoning 150,000-snake python population in Florida’s Everglades National Park threatens crops, livestock, and native animals. And, as the July 1 story of the toddler killed by a pet python demonstrates, the snakes can also threaten human lives. The snake overpopulation began when python owners discarded their unwanted pets in the wild; now, lawmakers are pushing for legislation to combat this invasive species. Not surprisingly, there is disagreement over the best way to do it.

Florida Senator Bill Nelson, who filed a bill in February to ban the importation of Burmese pythons, told a Senate panel on Wednesday that the snakes are slithering their way into a wider geographical area. Then he explained in graphic detail how a pet python… strangled a toddler in her crib last week in a town northwest of Orlando. ”It’s just a matter of time before one of these snakes gets to a visitor in the Florida Everglades,” Nelson said [Miami Herald]. Nelson said he’s been pestering the U.S. Fish and Wildlife Service for three years to halt the growth of the snake population, but the agency has not yet taken action. In addition, an environmental scientist at the panel emphasized the need to majorly restructure the policies that regulate and control import of exotic species like the python.

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Many animals depend on stealth to catch prey, but a small tentacled water snake resorts to downright trickery. That’s what a Vanderbilt University scientist found when he analyzed the way the snake captures fish, according to a study published in the Proceedings of the National Academy of Sciences.

The snake, which is native to Southeast Asia, takes advantage of a well-known reflex that fish possess. The mechanism occurs when a fish’s ear senses changes in water pressure due to movement nearby, which is all it takes to initiate the fish’s escape response, called the C-start — one of the most well studied neural circuits in vertebrates. Two large nerve cells, known as Mauthner cells, run along either side of the fish’s body and detect water disturbances. The cell closest to the signal will fire action potentials that stimulate trunk muscles on the opposite side of the body while simultaneously inhibiting the muscles on the near side. As a result, the fish turns away from the disturbance and flees. This whole process takes less than a tenth of a second [The Scientist]. The reflex causes the fish’s body to form a “C” as it turns away from the source of the underwater vibration—but in this case, that leads the fish right into the snake’s jaws.

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Snakes certainly make it look easy when they slither forward, leaving perfect S-curve tracks behind them, but scientists have long been puzzled by the mechanics of their locomotion. One theory proposed that they propelled themselves by pushing off small twigs and rocks in their paths, but researchers noted that they move equally well across smooth surfaces, like flat rock or desert sand. One researcher who is studying snakes’ motions, David Hu, notes that snakes are champs at escaping across office carpet…. “One snake escaped, and we didn’t know where it was until we got a printer jam,” he says. (The snake was fine.) [ScienceNOW Daily News].

Now, after a series of experiments and some computer modeling, Hu says his team has cracked the case. A snake’s scales, Dr. Hu said, resemble overlapping Venetian blinds, and tend to catch on tiny variations in the surface they lie on. This friction is greater in the forward direction than in sideways directions, as it is with wheels and ice skates. This frictional difference results in the snake’s moving forward as it undulates [The New York Times].

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In a coal mine in Colombia, researchers have unearthed the fossilized remains of the mother of all snakes, a nightmarish tropical behemoth as long as a school bus and as heavy as a Volkswagen Beetle [Los Angeles Times]. The new species, named Titanoboa cerrejonensis, is related to modern boa constrictors, but those descendants are puny in comparison to their primordial ancestor. Titanoboa grew up to 43 feet long and weighed about 2,500 pounds, researchers say, making it the largest snake on record.

The researchers used a known mathematical relationship between the size of vertebrae and the length of the body in living snakes to estimate the size of the ancient animal [BBC News]. Researchers say the ancient boa lived in the wet, tropical rainforest about 60 million years ago, and may have dined on giant turtles and primitive crocodiles–the fossilized remains of those animals were found near the snake fossils. But the extinct snake isn’t just interesting because of its superlative size; researchers also used it to investigate the Earth’s climate in the snake’s day.

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