In breeding programs aimed at conserving animals from small or isolated populations, scientists must balance the competing needs of adding genetic diversity and avoiding the introduction of harmful genes. 

Ever wanted to know how long a hippo can stay underwater? How they “dance” so gracefully through the water? Or how long they sleep?

Last month, after days of anticipation, Mabel, a 4-year-old pygmy hippopotamus at the San Diego Zoo, gave birth to her first calf.