Shera, an female African lion that resides at the Smithsonian's National Zoo, nurses her four newborn cubs on Aug. 31. The birth of the cubs, which belong to a vulnerable species of lion, gives hope to conservationists.

 

“We will be closely monitoring how she reacts to her cubs," said Kristen Clark, a lion and tiger keeper at the zoo, "since there is a possibility that she could reject them."