News of the Wild: Sharks, Sage-Grouse and Ants
From the October/November 2010 issue
Roger Di Silvestro
The Shark's Stereo Schnoz
A new study indicates that a shark can tell the exact moment the scent of food reaches each of its nostrils. If a delay of less than half a second occurs between when each nostril gets the message, the shark will turn in the direction of the nostril that received the scent first, because the food or prey is likely to be on that side. Longer delays, or no delays, do not affect shark movement, however. Scientists think that the use of a time lag in detecting odors may help explain the evolution of the hammerhead shark’s odd fore end: The wider space between nostrils may help the animals refine their detection of prey, potentially giving them better olfactory capabilities than pointy-nosed sharks, says Jayne Gardiner, the University of South Florida biologist who headed the study.
Can Sage-Grouse and Cattle Mix?
Promising new research from Oregon suggests so. These chicken-sized birds, being considered for the federal Endangered Species List, depend on sagebrush shrubs and on grasses beneath the shrubs for nesting habitat, but cattle graze this undergrowth. Scientists at the Eastern Oregon Agricultural Research Center have discovered, however, that cattle feed first on grasses growing between, rather than under, sagebrush. “Cattle consumption of grasses under shrubs is minimal until grasses between shrubs become limiting,” says researcher Chad Boyd. He and his colleague David Ganskopp concluded that cattle and grouse could coexist in nesting habitat if ranchers moved cattle to new grazing lands when the livestock had eaten 40 percent of the available forage, suggesting a promising management tool for saving the dwindling species without shutting down grazing on public land.
City Ants vs. Country Ants
Odorous house ants—so named because they smell like piña coladas when irritated—adopt a whole new lifestyle when they move from woods to city, according to Purdue University researcher Grzegorz Buczkowski, who studies the ants in Indiana. In their native forests, each colony of these social insects consists of a single queen and no more than 100 other ants—small enough to live in a single acorn. But in West Lafayette, Indiana, and nearby urban areas the scientist found colonies that numbered 58,000 ants with 238 queens. Some large colonies have connected via trails, creating supercolonies, one of which included thousands of queens and 6 million workers. The insects may be moving into cities because life there is easier than in the woods, where ants in unheated acorns hibernate in winter; in cities, they can find warm locales and stay active year-round. “Even when it’s snowing outside, they can be happy inside reproducing,” Buczkowski told a Science News reporter.