Giant panda Mei Xiang, together with her cub Bao Bao at the National Zoo in 2014. As of Saturday, Bao Bao now has another sibling: Her mother just gave birth to a cub. Chip Somodevilla/Getty Images hide caption

itoggle caption Chip Somodevilla/Getty Images

African forest elephants stampede in the Central African Republic jungle. Courtesy of Cornell Lab or Ornithology hide caption

itoggle caption Courtesy of Cornell Lab or Ornithology

A pangolin is released into the wild by officials at a conservation forest in Indonesia in 2013. The animal was among 128 pangolins confiscated by customs officers from a smuggler's boat off Sumatra. Jefri Tarigan/AP hide caption

itoggle caption Jefri Tarigan/AP

Dr. Claire Guest, co-founder of Medical Detection Dogs, says one of her dogs sniffed out her own breast cancer. Janine Warwick hide caption

itoggle caption Janine Warwick

Young pigs stare out of a pen at a hog farm in North Dakota. In coming months, consumers will start to see a new label on some packages of pork: Produced "without the use of ractopamine." Will Kincaid/AP hide caption

itoggle caption Will Kincaid/AP

Common marmosets can copy the sounds and intonations of their parents. iStockphoto hide caption

itoggle caption iStockphoto

A brown bear in its natural habitat. Wildlife ecologists in Minnesota found that black bears in their study experienced an increase in heart rate when buzzed by drones. iStockphoto hide caption

itoggle caption iStockphoto

Humpback whales and tanker in Stellwagen Bank National Marine Sanctuary in Massachusetts Bay. Green Fire Productions/Flickr hide caption

itoggle caption Green Fire Productions/Flickr

Penn State grad student Carley Miller holds up a bumblebee she collected from the wildflower patch on Penn State University's research farm near State College, Pa. Researchers are testing how planting "pollinator strips" of wildflowers near farm fields could help support wild bee populations. Courtesy of Lou Blouin hide caption

itoggle caption Courtesy of Lou Blouin

A juvenile California two-spot octopus (Octopus bimaculoides). Michael LaBarbera/Nature hide caption

itoggle caption Michael LaBarbera/Nature