March 21, 2007

This week in natural history...

Posted by: Rebecca Durkin

Climate change shaping evolution?
Researchers predict that as winters continue to warm, sheep bodies will get smaller
A team of researchers has linked changes in shape and size trends in Scottish sheep populations to the influence of climate change. Analyzing twenty years of data, the researchers were able to demonstrate the connection – harsh winter weather favors larger bodies, but as average winter weather warmed over recent years, there is less selection for the once favorable larger bodies. “People have argued for a long time that climate change is leaving an ecological legacy, but we have shown it will leave an evolutionary legacy too,” researcher Tim Coulson told the BBC.

Digging up digging dinos
The first definitive evidence of burrowing dinosaurs was discovered in Montana, unearthed from a chamber at the end of a tunnel. The dinosaur, named Oryctodromeus cubicularis, meaning "digging runner of the lair," was built for digging with a snout, shoulder girdle, and pelvis morphologically similar to those of burrowing animals. Researchers suggest that the burrowing lifestyle of the small, 95 million-year-old specimens provided shelter, a place to rear young, and possible protection from environmental extremes.

American Crocodile no longer endangered
On Tuesday, the once “endangered” American crocodile was downgraded to a “threatened” status by the U.S. Fish and Wildlife Service. The species is still protected by the Endangered Species Act, but the new classification implies a positive trend in its population recovery. Under its protected status and the preservation of South Florida habitat, the species has gone from an estimated population of 300 in 1976 to up to 2000 today. The American crocodile remains endangered in Central and South America.

- Rebecca