The Decline and Fall of Mammoths
What doomed the woolly mammoth? The blame has sometimes been fixed on human hunters, but a study from the University of London and elsewhere argues otherwise. Analyzing DNA from mammoth bones, teeth and tusks from Siberia and Alaska, the researchers identified two major mammoth lineages. One died out about 43,000 years ago, before human beings could have had much impact. The other lineage declined until 12,000 years ago, when hunters may have finished off the last of the beasts.
Against the odds, wildlife is flourishing in southern Sudan, beset by a 21-year civil war until 2005 (conflict continues in the western region of Darfur). Wildlife Conservation Society biologists, in the first aerial survey since 1982, estimate there are 1.2 million ungulates and 8,000 elephants.
Clownfish "chirp" and "pop" to defend territory or attract mates. Scientists from Belgium and Virginia, using X-rays and high-speed video, found that the fish has a specialized jaw ligament that snaps its teeth together to make these noises.
Plants may be better pioneers than people realized, according to a new study led by University of Oslo researchers. They analyzed DNA from nine species of flowering plants in Svalbard, a remote island group between Norway and the North Pole, to see where the plants had come from. The plants had originated with seeds from distant locations and different directions—Greenland, Scandinavia, even Russia—probably via air, bird droppings, ice floes and driftwood. Conclusion: suitable habitat—not seed dispersal—determines a species' range.
NAME: Euchaetes egle, or Milkweed Tiger Moth.
POTENTIAL FOOD FOR: Red bats and big brown bats.
FAVORITE GAMBIT: Sounding gross. Literally. They don't taste gross, at least not to bats. But they deter their predators, which hunt by sonar, by imitating the high-pitched clicking sounds of certain other moths that taste so bad that bats steer clear.
BATS FALL FOR THAT?: A Wake Forest University study shows that they do. In fact, it's the first time researchers have demonstrated that acoustic mimicry, like visual mimicry—think of those butterflies that look like foul-tasting monarchs—can fool predators.