Fancy feathers are usually thought to be for good looks. But head plumage helps the whiskered auklet of the Aleutian Islands avoid obstacles in the dark, say researchers at Memorial University in Newfoundland. They taped the head feathers down and observed the birds exploring a dark maze designed to mimic the rock crevices where auklets nest. The birds bumped their heads nearly three times more often than birds with the use of their feeler feathers.
Joshua trees, the distinctive yuccas of the Mojave Desert, are evolving in step with moths, according to researchers at the University of Idaho. Plants in the eastern part of the Joshua trees' range have shorter stylar canals—the part of the flower that receives pollen—than do western ones. Turns out that two different species of yucca moths pollinate Joshua trees when they lay eggs. And the length of the canal corresponds to that of the local moths' egg-laying appendages.
A Soft Body but a Hard Bite
The tip of a Humboldt squid's beak is one of the hardest organic materials known. In fact, researchers have wondered why the beak doesn't shred the squid's own soft, gelatinous tissue when the animal bites its prey. (Imagine holding a knife blade with no handle and trying to carve a tough roast.) The key, say scientists at the University of California at Santa Barbara, is that the base of the beak, which is attached to the rest of the squid's mouth, is 100 times more pliant than the tip.
Standing up Straight and Tall
The bone on the right is a modern human femur. The bone on the left is a slightly damaged six-million-year-old femur from the oldest known human ancestor, Orrorin tugenensis, discovered in 2000 in Kenya. How did our ancestor move? A new analysis led by George Washington University confirms that Orrorin walked on two legs.
Name: Heliconius erato and Heliconius melpomene, two species of butterfly common in Central America.
At First Sight: They look alike. The main upside to their resemblance is enhanced protection. Both species are noxious, and predators learn to avoid them. The butterflies' similar appearance imparts the don't-eat-us lesson more efficiently.
On Second Thought: One downside to their resemblance is frustration, say researchers at the Smithsonian Tropical Research Institute. In experiments with H. erato and H. melpomene, males spent considerable time futilely courting females of the wrong species. Other mating cues, presumably olfactory, eventually set the guys straight.