After release from rehab, bottlenose Billie started walking on water with her tail. Studying how the behavior spread could offer clues about how animals learn from each other.
Although highly controversial now, keeping orcas in captivity helped transform popular and scientific conceptions of the marine mammal from an unfeeling killer to a complex, intelligent animal.
Overlooked for half a century, a skull in the Smithsonian collection points to a dolphin species that lived 25 million years ago, according to a study.