- News Home
17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
ScienceShot: Dino Bones Heat Up
27 June 2012 1:05 pm
Next to the mystery of what exactly killed the dinosaurs, the biggest head scratcher has been whether they were warm- or cold-blooded. Many studies have hinted that dinosaurs had an active lifestyle, a sign of warm blood, but their bones tell a different story: They often contain tree-ring-like features, called lines of arrested growth (LAGs), which have been linked to lengthy episodes of slow metabolism in a variety of modern-day reptiles and other cold-blooded creatures. In some studies of well-preserved fossils, researchers have used LAGs to help determine the ages of Tyrannosaurus rex and other dinosaurs when they died. But in a first-of-its-kind analysis, published online today in Nature, researchers report that the bones of many mammals contain LAGs, too. The scientists looked at bone samples from more than 100 wild individuals representing 41 species of ruminants—plant-eating mammals that have a four-chambered stomach—from a variety of ecosystems ranging from Norway's high-arctic islands of Svalbard to the southern tip of Africa. They found that all of the species, including the red deer Cervus elaphus (right), had LAGs (denoted by arrows in bone sample from the species, left). Although the causes of the features in these mammals aren't clear, the new finding shows that LAGs do not a cold-blooded creature make. So consider this one more dino mystery that has yet to be solved.
See more ScienceShots.