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Tails win: Gecko tails dance to avoid predators

Lizards are well known for snapping off their tails when a predator snags them from behind, but that defense strategy doesn’t mean it's game over for the disembodied tail. The abandoned appendage has a network of neurons that guides it to flail about even after losing its connection to the brain.

Biologists at Clemson University and the University of Calgary noticed that the movements of the luckless tails of leopard geckos seemed more complicated than those of other lizard tails. So the scientists tracked the gecko tails post-snap and found that they jump, flip and lunge, presumably to distract predators and give the gecko time to make its getaway.

"No one had ever documented anything other than simple swinging, sort of like a pendulum,” says Timothy Higham, an assistant professor in the Department of Biological Sciences at Clemson. Higham and Anthony Russell at the University of Calgary published their results last week in Biology Letters.

Of pathogens and pets: Tokay gecko harbors 10 types of salmonella

ALBUQUERQUE—The foot-long Tokay gecko's polka-dot skin and wide eyes have made it popular with pet stores, where it can sell for less than $20. But the adorable Asian lizards are also a mixing pot for 10 types of salmonella from local livestock, poultry and rodents, a researcher said today.

For the last several years, Katherine Smith at Brown University and colleagues have worked to document the pet trade's potential to bring new and dangerous diseases to the United States. As Smith reported in Science earlier this year, the U.S. imported 1.5 billion live animals between 2000 and 2006, just 14 percent of which have been identified to species in government records. Even less well-known are the pathogens they may contain. In 2003, for instance, a Gambian pouched rat started an outbreak of monkeypox in the Midwest.

At the Ecological Society of America meeting here today, Smith described new results from a study of 150 wild-caught Tokay geckos imported from Indonesia. She found that 60 percent of the geckos tested positive for Salmonella, which was not too surprising considering that 10 percent of salmonella cases are caused by reptile pets, such as slider turtles and iguanas.

A lizard that swims through sand

lizard swims through sandWhat slithers like a snake, swims like a fish and lives in the Sahara? The sandfish lizard, of course. This small reptile, which measures just 10 centimeters long, can swim through the sand dunes at up to 15 centimeters per second. But how does it do it?

Researchers at the Georgia Institute of Technology used a high-speed x-ray camera to peer through the sand and see. The little lizards, it turns out, use a far different mode of locomotion under the sand than they do at the surface.

“Once below the surface they no longer use their limbs for propulsion," study leader Daniel Goldman said in a statement. “Instead they move forward by propagating a traveling wave down their bodies like a snake.”

Komodo dragon kills with venom, not bacteria

komodo dragon kills prey with venomKomodo dragons (Varanus komodoensis) can't chomp as hard as crocodiles and aren't as massive as grizzly bears, so how do they kill huge deer and even humans?

It's all in the bite and a dose of venom—not bacteria, as some previous research had suggested. The dragons, native to a handful of central Indonesian islands, use serrated teeth to "grip and rip" prey, creating a deep wound. Then they add their own special blend of venom, according to study results that were just published online in Proceedings of the National Academy of Sciences.

"The dragon is truly poisonous," Stephen Wroe, a biological research fellow at University of New South Wales in Australia and study author, said in a statement.

Like a virgin: Shark spawns sans help

An Atlantic blacktip shark spontaneously reproduced without the company of a mate, scientists report in the second documented case of the phenomenon.

Five-foot-long (1.5-meter) Tidbit, the ironically named resident of the Virginia Aquarium & Marine Science Center in Virginia Beach, Va., spawned on her own — no male assistance involved, according to Reuters. Sadly, Tidbit died in May 2007 during a veterinary checkup, before birthing her until-then unknown 10-inch-long shark pup. The case is published in the new issue of the Journal of Fish Biology.

Scientists last year wrote about an asexual hammerhead shark that reproduced on its own, a process called parthenogenesis in which unfertilized eggs divide. Bony fish, reptiles, birds, lizards and Komodo dragons also can reproduce asexually.

New adhesive is stickier than gecko feet and doesn't lose its grip

Researchers say they have developed an adhesive that can stick stronger than the toes of geckos. The little lizard can dash up walls and hang from the ceiling by a single toe, thanks to microscopic hairs on the soles of its feet that latch onto nooks and crannies on surfaces.

A team of materials scientists (from the University of Dayton, Wright-Patterson Air Force Base, the University of Akron, and the Georgia Institute of Technology) report in Science today that they used carbon nanotubes (tiny tubes of carbon about 1/50,000th the width of a human hair) to model the shape of gecko microhairs (each hair is straight with a curly top).

Lizards grow up so fast these days

A new chameleon species has what may be the briefest, oddest life cycle of any four-legged animal. Researchers were puzzled to find during repeated trips to southwestern Madagascar, home to Labord's chameleon (Furcifer labordi), that the lizards quickly went from adulthood to dead, with no juveniles or other stragglers. After studying about 400 of the critters, they pieced together the life cycle: The chameleons reproduce in January and February; the offspring hatch simultaneously in November and begin a mad dash to sexual maturity, growing up to 0.1 inch (2.6 millimeters) daily. After 60 days, males have tripled or quadrupled in body size and are ready to breed. All told, the lizards live for a mere four to five months after hatching. Tetrapods (four-legged animals), including mammals, birds, lizards and amphibians, typically live two to 10 years—with notable exceptions, such as long-lived humans and turtles. Researchers report in Proceedings of the National Academy of Sciences USA that this may explain why some chameleons die so rapidly in captivity.


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