Tai Shan on his first birthday. The panda was conceived in 2005 through artificial insemination in a procedure performed by National Zoo scientists and veterinarians. Ann Batdorf/Smithsonian Institution via AP hide caption

itoggle caption Ann Batdorf/Smithsonian Institution via AP

An artist's rendition of two Sinosauropteryx dinosaurs, showing their short, bristle-like feathers along the midline of the head, neck, back and around the tail, forming irregular stripes. Chuang Zhao and Lida Xing hide caption

itoggle caption Chuang Zhao and Lida Xing

The ring-tailed lemur is one of many pint-sized creatures on the island of Madagascar. Scientists have long noted that despite the great diversity of fauna on the island, there are few large beasts, like the lions and elephants found on mainland Africa. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Researchers dyed sperm from each deer mouse a different color; in this case, red represents one male and green another. The sperm joined together with their own kind, as seen here, allowing them to swim faster than those that did not cluster together. Heidi Fisher hide caption

itoggle caption Heidi Fisher

After the morning milking, the cows head out to graze on the 146-acre farm. Kathleen Masterson/NPR hide caption

itoggle caption Kathleen Masterson/NPR

Red snapper caught by commercial fishermen await shipment on a dock in South Carolina. South Atlantic Fishery Management Council/AP hide caption

itoggle caption South Atlantic Fishery Management Council/AP

Sudan, one of four endangered northern white rhinoceroses shipped to Kenya from a zoo in the Czech Republic, explores his new pen at the Ol Pejeta reserve near the town of Nanyuki in central Kenya. Tony Karumba/AFP/Getty Images hide caption

itoggle caption Tony Karumba/AFP/Getty Images