Panthers roam in rural Collier County, in southwest Florida. As the Florida state animal's population has grown, wildlife officials may seek to take the panther off the endangered species list. Courtesy of the Conservancy of Southwest Florida hide caption

itoggle caption Courtesy of the Conservancy of Southwest Florida

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

U.S. Fish and Wildlife Forensics Lab Director Ken Goddard holds a wood sample used in the lab's forensic work in Ashland, Ore. Jes Burns/OPB/EarthFix hide caption

itoggle caption Jes Burns/OPB/EarthFix

Family means a lot on Cayo Santiago, an island and monkey research colony off the coast of Puerto Rico. The colony of rhesus macaques living on the island since the 1930s has allowed scientists to trace kinship ties and effects across an extended community. Anders Kelto/NPR hide caption

itoggle caption Anders Kelto/NPR

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

AquaBounty's salmon (background) has been genetically modified to grow bigger and faster than a conventional Atlantic salmon of the same age (foreground.) Courtesy of AquaBounty Technologies, Inc. hide caption

itoggle caption Courtesy of AquaBounty Technologies, Inc.

This undated photo from the San Diego Zoo shows Speed, a Galapagos tortoise that has been at the zoo since 1933. The zoo reported Friday that Speed had been euthanized at an estimated age of more than 150 years. AP hide caption

itoggle caption AP