A rescued manatee suffering from exposure to an algae bloom called red tide in southwest Florida comes up for air as it swims into a critical care tank at Tampa's Lowry Park Zoo. Steve Nesius/Reuters/Landov hide caption

itoggle caption Steve Nesius/Reuters/Landov

Thousands of "fairy circles" dot the landscape of the NamibRand Nature Reserve in Namibia. Why these barren circles appear in grassland areas has puzzled scientists for years. N. Juergens/AAAS/Science hide caption

itoggle caption N. Juergens/AAAS/Science

Workers clear honey from dead beehives at a bee farm east of Merced, Calif. Marcio Jose Sanchez/AP hide caption

itoggle caption Marcio Jose Sanchez/AP

On Australia's Heron Island, buff-banded rails like this one have become the avian equivalent of a weed. Richard Harris/NPR hide caption

itoggle caption Richard Harris/NPR

The bucardo, or Pyrenean ibex, lived high in the Pyrenees until its extinction in 2000. Three years later, researchers attempted to clone Celia, the last bucardo. The clone died minutes after birth. Taxidermic specimen, Regional Government of Aragon, Spain Robb Kendrick/National Geographic hide caption

itoggle caption Robb Kendrick/National Geographic