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They are ugly, and they are poisonous. And now scientists have discovered that they carry switchblades.

Stonefish, a group that includes many species, have a previously unknown defensive weapon: a "lachrymal saber" in each cheek that can be drawn and retracted as needed.

As if their bony spines, irregular shapes and gaping mouths did not make them frightening enough, they can stick out the blade and keep it in a locked position, like a ratchet with slanting teeth that allows movement in one direction only.

Stonefish can release the blade by flexing their jaws, pulling it back once they no longer feel so unsettled. W. Leo Smith, an evolutionary biologist at the University of Kansas, said they stick the knife out when you approach with a net, so it appears to be used for defense.

DARPA seeks to boost rocket launches

In the 1960s, a rocket launch was big news all over the world. Sixty years later, it's still a big deal. But the ability to make space travel a reliable, everyday event is still a way off.

The U.S. government and some private companies want to change that. The Pentagon's Defense Advanced Research Projects Agency, or DARPA, is putting up $10 million to encourage launch firms to get faster and nimbler about traveling to space. The goal of the Rapid Launch Challenge is to hurl a small satellite into orbit with only a day's notice — or less — from virtually anywhere in the country. "The real goal has always sort of been to enable a more real-time, tactical use of space," said Todd Master, a DARPA program manager.

Giant salamander vanishes in the wild

The Chinese giant salamander, the world's largest amphibian and a critically endangered species, has quietly slipped toward extinction in nature. After an exhaustive, yearslong search, researchers reported that they were unable to find any wild-born individuals.

Millions of giant salamanders live on farms scattered throughout China, where the animals are bred for their meat. But Samuel Turvey, a senior research fellow at the Zoological Society of London. said reintroducing farmed animals is not a simple solution for saving the species in the wild.

In the wild, Chinese giant salamanders were not just one species but at least five, and perhaps as many as eight. On farms, they are being muddled into a single hybridized population adapted to no particular environment. "The farms are driving the extinction of most of the species by homogenizing them," said Robert Murphy, a co-author and senior curator of herpetology at the Royal Ontario Museum. "We're losing genetic diversity and adaptations that have been evolving for millions of years."

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