During a raid on a Missouri dogfighting ring, Tim Rickey of the ASPCA holds Dharma, a pit bull who lost part of her leg in a fight. Courtesy of the Humane Society of Missouri hide caption

itoggle caption Courtesy of the Humane Society of Missouri

Wildlife biologist Anthony Fischbach observes a tagged walrus near Point Lay, Alaska, earlier this month. Tens of thousands of walruses have come ashore in northwest Alaska because the sea ice they normally rest on has melted. U.S. Geological Survey/AP hide caption

itoggle caption U.S. Geological Survey/AP

Cheetahs walk across a savannah at the Mashatu game reserve in Botswana. Cameron Spencer/Getty Images Europe hide caption

itoggle caption Cameron Spencer/Getty Images Europe

A male Florida panther walks down Jane's Scenic Drive in Fakahatchee Strand Preserve State Park. Before scientists bred the Florida panthers with cats from Texas, they lacked vitality and were near extinction. Science/AAAS hide caption

itoggle caption Science/AAAS

This handout photo from New Zealand's Department of Conservation shows one of 40 pilot whales that died after beaching themselves at Spirits Bay, northwest of Auckland. Department of Conservation/Getty Images hide caption

itoggle caption Department of Conservation/Getty Images

Archaeologists have unearthed a wealth of new information about dinosaurs in the past decade thanks in large part to new technology.  But the T. Rex's telegenic charisma and popular appeal are something that even scientists aren't immune from. Ethan Miller/Getty Images hide caption

itoggle caption Ethan Miller/Getty Images

Smoke rises from surface oil being burned near the Deepwater Horizon blowout. The well spewed nearly five million barrels of oil, making it the world's largest accidental marine oil spill. Joel Sartore/National Geographic hide caption

itoggle caption Joel Sartore/National Geographic