Animal Behavior

The windshield of Dave Hawks' 1994 Toyota 4Runner is splattered yellow, but Hawks doesn't mind. He's speeding north on U.S. 395, past Adelanto, Boron and Ridgecrest and running the wipers would only make matters worse. Besides, it's now a point of discussion. "It's all the fat in their bodies," he says, explaining why this butterfly -- the painted lady -- makes such a distinctive impression. "They need that fat for energy because they have such a long migration."

Desert locusts are normally solitary individuals who eke out a meager subsistence while avoiding others of their species. But when food sources become abundant, such as after a rain, they transform into ravening packs of billions of insects that can strip a landscape bare. The key to the transformation, researchers said Friday, is the brain chemical serotonin, the chemical that in humans modulates anger, aggression, mood, appetite, sexuality and a host of other behaviors.

The equivalent of nine glasses of wine a night is just dinner to the pen-tailed tree shrew, a small Malaysian mammal resistant to the effects of chronic drinking, researchers reported Tuesday in the Proceedings of the National Academy of Sciences. The shrew's drink of choice is bertam palm nectar, naturally fermented to have an alcohol content up to 3.8% -- just a few tenths of a percent shy of Guinness Draught beer.

Contrary to the long-standing image of female bonobos as the peaceful matriarchs of their species, scientists have observed the creatures capturing, killing and eating young monkeys in the lowland evergreen forests of Salonga National Park in the Democratic Republic of Congo. The discovery undermines the conventional wisdom that hunting among primates is an outgrowth of male dominance and aggression, according to a study published Tuesday in the journal Current Biology.

Biologists exploring the ocean floor for new sea creatures have stumbled upon one of the largest known single-celled creatures, a bland, grape-sized distant cousin of the amoeba that may solve a thorny evolutionary question that has puzzled researchers for decades.

Cocaine repels most insects -- which is why the coca plant makes the chemical in the first place. But in a surprising new finding, U.S. and Australian researchers reported Friday that honeybees are susceptible to the drug's insidious lure. They become addicted, and even suffer withdrawal symptoms when they no longer have access.

WHAT could be wrong with Shadow? The green-eyed, long-haired cat had adapted well to his Santa Monica home. There was a carpeted cat tree in the living room for his climbing pleasure. He appeared to have reached an understanding about sharing the house with the other resident feline. Then one day his owners saw wet spots around the house: Shadow was urine-spraying. The door was a favorite target. So was the side of the sofa. And a corner wall of the living room.

Tom and Jerry, two snow leopard cubs, scampered across the smooth rocks of their Los Angeles Zoo exhibit, preparing to practice their ambush skills on each other. Tom -- or maybe Jerry -- peered down and leapt off the rock onto the back of the other cub. Jerry -- if it was Jerry -- shook him off and the two darted across their grounds, a flurry of black spots on white fur and fluffy tails. The afternoon temperature on Tuesday felt as though it barely reached 50 degrees -- nippy by L.A.

More pregnant polar bears in Alaska are digging snow dens on land instead of sea ice -- a phenomenon that researchers say is probably related to global warming. From 1985 to 1994, 62% of the bears studied dug dens on sea ice. From 1998 to 2004, just 37% gave birth on sea ice, according to the study by three U.S. Geological Survey researchers. Bears that continued to den on ice moved east in the Beaufort Sea off Alaska's northern coast, away from ice that was thinner or unstable.