Littlejohn’s tree frog has reproduced in captivity for the first time, offering new hope for the survival of this endangered ...

Five-day-old red-eyed treefrog embryos are tightly curled inside dehydrated eggs packed closely together. It’s dry enough to make them begin to hatch early amid heating. Karen M. Warkentin As the frog ...

Fight or flight. They’re basic animal responses once considered purely instinctual—or perhaps strictly a natural learning process—but they may actually be a combination of the two. According to ...