Mammoths had a distinctive version of a gene known to play a role in sensing outside temperature, moderating the biology of fat and regulating hair growth. That bit of DNA likely helped mammoths thrive in cold weather, scientists say. Courtesy of Giant Screen Films, 2012 D3D Ice Age, LLC/Penn State University hide caption

itoggle caption Courtesy of Giant Screen Films, 2012 D3D Ice Age, LLC/Penn State University

One of the 20 GPS sensors deployed on Greenland's Helheim Glacier to track its movement. Alistair Everett/Swansea University hide caption

itoggle caption Alistair Everett/Swansea University

An illustration of Pappochelys, based on its 240-million-year-old fossilized remains. This ancestor to today's turtle was about 8 inches long. Rainer Schoch/Nature hide caption

itoggle caption Rainer Schoch/Nature

The long "oral arms" of the adult moon jelly, Aurelia aurita, extend from near its mouth, in the center of the bell. Magnus Manske/Wikimedia Commons hide caption

itoggle caption Magnus Manske/Wikimedia Commons

An artist's conception of how Saturn's immense Phoebe ring might appear to eyes sensitive to infrared wavelengths. NASA/JPL/Space Science Institute hide caption

itoggle caption NASA/JPL/Space Science Institute

A blood test developed by Harvard researchers checks for evidence of past infection with more than a thousand strains of virus, from about 200 virus families. The swine flu virus shown here, A/CA/4/09, rarely infects humans. C. S. Goldsmith/CDC hide caption

itoggle caption C. S. Goldsmith/CDC
Gustav Dejert/Ikon Images/Getty Images

One of these things is not like the other: A 3-D printed model of a beige cowbird egg stands out from its robin's egg nest mates, though their shape and heft are similar. Ana Lopez/Courtesy of Mark Hauber hide caption

itoggle caption Ana Lopez/Courtesy of Mark Hauber

This fungus among us — baker's yeast, aka Saccharomyces cerevisiae — is useful for more than just making bread. iStockphoto hide caption

itoggle caption iStockphoto

The most recent common ancestor of all today's snakes likely lived 120 million years ago. Scientists believe it used needle-like hooked teeth to grab rodent-like creatures that it then swallowed whole. Julius Csotonyi/BMC Evolutionary Biology hide caption

itoggle caption Julius Csotonyi/BMC Evolutionary Biology

The skull of a chicken embryo (left) has a recognizable beak. But when scientists block the expression of two particular genes, the embryo develops a rounded "snout" (center) that looks something like an alligator's skull (right). Bhart-Anjan S. Bhullar hide caption

itoggle caption Bhart-Anjan S. Bhullar

ADP Co-chairs Daniel Reifsnyder (left) and Ahmed Djoghlaf (center) say their negotiation work is difficult but worth it. "We only have one planet, you know," Reifsnyder says. "We have to protect it." Courtesy of IISD/ENB hide caption

itoggle caption Courtesy of IISD/ENB

Loki's Castle, the field of deep sea vents between Norway and Greenland, is home to sediments containing DNA from the newly discovered archaea. R.B. Pedersen/Centre for Geobiology, Bergen, Norway hide caption

itoggle caption R.B. Pedersen/Centre for Geobiology, Bergen, Norway