Cane Toads to Need Canes?

The cane toad (Bufo marinus) is one of the world's famous invasive species. Originally from South and Central America, these toads were introduced to Australia in the 1930s to control pests. But with almost no predators, the toad population exploded, pushing out native species as it grew. Now it looks like some toads are paying a price.

Scientists in Australia studied the toads on the outermost edge of their population. If cane toads are an invading army, then these soldiers are on the front line. In each generation, the biggest and fastest hoppers travel the farthest, so the "front line" toads today are descended from a whole line of fast hoppers.They have big bodies and long legs. And about 10% of these toads have another feature in common: misshapen spines, caused by arthritis. The scientists say big hops and hard landings put pressure on these toads' skeletons, while weakened immune systems make them vulnerable to arthritiscausing bacteria.

Cornet Makes Its Own Spotlight

Comet Holmes, which orbits our sun once every 7 years, used to be visible only through a telescope. But astronomers watching the comet pass by Earth last October were startled to see it suddenly flare up. It became one million times brighter, and visible to the naked eye. No, comet-dwelling aliens didn't discover electricity. Scientists say the brightening was due to an explosion, which threw up a large cloud of dust and gas around the comet. But no one is sure how this explosion was caused. It could have been the result of a buildup of gas under the comet's surface, or a collision with a meteoroid.

I, Cockroach

Every cockroach is equal. No queen or king cockroach calls the shots. Instead, each individual follows a few simple rules. "Safety in numbers" is one of those rules; another is "Head for dark places." A group of roaches following these rules will end up clumped together in a dark place, seeming to have decided as a group, or been instructed by a leader, to do so.

Jose Halloy and other scientists created tiny, boxy robots that smelled like cockroaches. When a few of the real roaches in a group were replaced by robots, the weak-eyed insects didn't notice. And when the robots were programmed to head to a lighter space instead of the preferable darker one, the roaches followed them 60% of the time. This showed that a few programmed "roaches" could change the behavior of the entire group. No word yet on whether the roaches can be convinced to walk into insecticide.

Don't Worry, It's Extinct

We live in a world where even the biggest, creepiest bugs are mostly squishable. But 390 million years ago, that was not the case. Before the time of the dinosaurs, there were gigantic arthropods-insects and other creatures with hard exoskeletons. A recent fossil discovery showed they might have been even bigger than we thought. Scientists in Germany found a foot-and-a-half-long claw that they say belonged to Jaekelopterus rhenaniae, the giant sea scorpion. Its owner would have been over 8 feet long, making it the largest arthropod that ever lived.

The higher level of oxygen in the ancient atmosphere, as well as the need to compete with other organisms, might have driven Jaekelopterus to reach such a great size.The scorpions could breathe on land as well as in water.They didn't have stingers yet-but they probably, at least sometimes, ate each other.

Goodbye, Alex

Alex, the African gray parrot famous for his extensive English vocabulary, died in September 2007 at age 31. Dr. Irene Pepperberg had spent most of her career with Alex, teaching him words as well as shapes, numbers and colors. Alex could count and describe objects, and could use English to communicate. Dr. Pepperberg's research showed animals were capable of much more than we'd thought.

Dr. Pepperberg worked with Alex on the last day he was alive. When she put him in his cage for the night, the parrot said, "You be good. see you tomorrow. I love you."

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