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Wild Things: Life as We Know ItExplore more photos from the story |
Fawn Patrol
Some pronghorn antelope that live to adulthood have wolves to thank, Wildlife Conservation Society researchers say. They monitored more than 100 fawns in Wyoming's Grand Teton National Park over three years. Oddly, the survival rate of those near wolves was four times higher than those in wolf-free areas. Why? Wolves kill or expel coyotes, which prey on young pronghorns. Where the antelope roam, ranchers and hunters who kill wolves may also be harming pronghorns.
A Monkey's Uncle
In Mississippi, newly analyzed fossils have revealed North America's oldest primate, Teilhardina magnoliana, a tree dweller that weighed barely an ounce and lived here 55.8 million years ago. The finding suggests that primates crossed the Bering land bridge from Asia (as humans would 55.785 million years later), says K. Christopher Beard of the Carnegie Museum of Natural History in Pittsburgh, who discovered the fossils.
Gasping for Breath
An ocean "dead zone" has been discovered off the Pacific Northwest. The water has so little oxygen that it "kills any marine animals that cannot swim or scuttle away," says Jane Lubchenco of Oregon State University. She and her colleagues analyzed 60 years of data and found that oxygen levels dropped in 2002. Most of the hundreds of dead zones worldwide are caused by pollution. But this one was caused by winds and currents that disrupted the ecosystem and fueled oxygen-depleting bacteria.
Survival in the City
Plants adapt quickly to life on the streets, according to a new study in Montpellier, France. Crepis sancta, a weed related to the dandelion, produces some seeds that are wind-borne and others that stay put. Compared with rural C. sancta, which scattered more seeds to the wind, city weeds produced more seeds that dropped, tapping into soil that had enabled their parents to survive in the concrete jungle.
Observed
Name: American alligator (Alligator mississippiensis)
On the Surface: The gator uses its lungs to breathe.
Under the Surface: The gator uses its lungs to maneuver, a new study shows.
In the Lab: Researchers at the University of Utah documented a dual purpose for many of the muscles that expand and contract the lungs. Underwater, those muscles move the gator's lungs toward its tail as it dives, toward its head as it surfaces and to either side as it rolls. The finding, say the researchers, explains why the gator can swim without fins or flippers. And they suggest this system is "an underappreciated but important means for other aquatic animals," such as some frogs, salamanders and turtles, to do the same.
Additional Sources
"Indirect effects and traditional trophic cascades: A test involving wolves, coyotes, and pronghorn," Kim Murray Berger et al., Ecology, March 2008
"The oldest North American primate and mammalian biogeography during the Paleocene-Eocene Thermal Maximum," K. Christopher Beard, PNAS, March 11, 2008
"Emergence of Anoxia in the California Current Large Marine Ecosystem," F. Chan et al., Science, February 15, 2008
"Rapid evolution of seed dispersal in an urban environment in the weed Crepis sancta," P.-O. Cheptou et al., PNAS, March 11, 2008
"Recruitment of the diaphragmaticus, ischiopubis and other respiratory muscles to control pitch and roll in the American alligator (Alligator mississippiensis)," T.J. Uriona and C.G. Farmer, The Journal of Experimental Biology, April 1, 2008
Comments
it is all about bouyancy. The gator is impressive
Posted by on April 29,2008 | 07:22AM
The video is way too long, especially before getting to the hypoxia event - most people won't watch that long. A simple voice over would greatly increase the video's value. Thanks, David
Posted by David Reinert on April 30,2008 | 09:45AM