Science  01 Nov 2013:
Vol. 342, Issue 6158, pp. 541
  1. A Sense of Snakes

    Sssee me?

    Primates are adapted to spot snakes.


    For 100 million years, snakes have shaped mammalian evolution by selecting for traits that help animals avoid them. Now, new research suggests primates are uniquely adapted to quickly spot a snake's features.

    Behavioral ecologist Lynne Isbell of the University of California, Davis, says the threat of snakes gave primates some of their defining features, including specialized visual centers in our brains. Isbell and a team of neuroscientists implanted electrodes in the brains of macaque monkeys to measure activity in their pulvinar—a cluster of neurons thought to help direct attention and recognize threats. The monkeys viewed four types of images: snakes, macaque faces, macaque hands, and geometric shapes. Forty percent of the neurons measured were most active in response to snakes; these snake-responsive neurons were the quickest to snap into action and fired more frequently.

    The results, published this week in the Proceedings of the National Academy of Sciences, suggest that primates have built-in mechanisms for spotting snakes, says Isabelle Blanchette, a cognitive psychologist at the University of Quebec, Trois-Rivières, in Canada. But in humans, higher brain processes, such as learning, may influence our behavior just as much as our instinctive snake sense.

  2. Most Earth-Like Exoplanet Yet

    Astronomers have discovered an extrasolar planet that's more Earth-like in its size and composition than any other exoplanet ever found. Kepler-78b is one of hundreds detected by NASA's Kepler spacecraft, which monitors the brightness of some 150,000 stars in our Milky Way galaxy in search of orbiting planets. Most of the exoplanets found so far have been gas giants: big balls of gas and dust that are several times larger in radius than Earth.

    Two groups of researchers used ground-based telescopes to follow up on Kepler-78b. This week in Nature, they report that the planet is 80% more massive than Earth and 20% larger in radius—making it just about as dense as Earth and suggesting that it is composed of rock and iron. But Kepler-78b orbits so close to its star—and is thus so infernally hot—that it can be described as more of a hellish cousin to Earth than a twin.

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