Wild Soay sheep on the islands of the St. Kilda archipelago in the North Atlantic have been measured and monitored by scientists for decades. All this data now explains why females have been slowly getting smaller with generations. 
Bisphenol A can leach into foods and drinks, especially when polycarbonate cracks, as shown in the cup above. 
A new study reveals more about how axolotls, a type of salamander, regenerate lost limbs. Scientists had thought that primitive, undifferentiated pluripotent stem cells gave rise to the new tissue. Now, researchers show that cells at the wound site retain their identity and give rise to the same cell types in the regrown limb. In a regenerated axolotl limb, shown here, scientist used green fluorescent protein to track the origins of the new growth. GFP-labeled Schwann cells from the original limb gave rise to the GFP-labeled Schwann cells visible here, which are wrapped around non-labeled nerv... 
Snow in the Rockies blushes a bit pink with desert dust that winter storms picked up from the Colorado Plateau and deposited along with the snow. 
This image depicts what the Mississippi delta would look like if land continues sinking and sea level rises one meter. (The town of Grand Isle sits on the coast today.) A new model predicts that 10 percent of Louisiana will be submerged by the year 2100. 
Overall, the ozone hole over Antarctica boosts wind speeds over the surrounding oceans, according to new model simulations. Yellow indicates where wind speeds increased the most in a scenario with an ozone hole compared to one without the hole. Bright blue shows where wind speeds declined the most. 
A male seed beetle's genetic quality can make a difference in how many of his offspring survive. Yet a new study finds that females shopping around for the good genes often don't get a good deal. 
This snapshot of a state-of-the-art simulation shows the flow of gas into a fledgling galaxy. Streams of cold gas (blue) flow onto the edge of the fledgling galaxy’s disk, while shock-heated gas (red) surrounds the disk. Gas enriched in metal content (green) by supernova explosions is stripped from smaller galaxies interacting with the hot dark matter halo and the cold gas stream. 
A new report concludes that people living in Europe more than 35,000 years ago made this flute, shown from three different angles, out of a vulture bone. A magnified portion of the flute, top, provides a closer look at two of the flute's finger holes. 
Using fluorescence detector telescopes at the Pierre Auger Observatory in Argentina, astronomers say they have found evidence that many of the highest-energy cosmic rays are iron nuclei rather than protons. Another cosmic ray observatory, however, reports no sign of iron. 
