Ginger, a 4-year-old North American river otter, gave birth to her first litter back in February. The boy and girl pup weighed approximately 3.5 ounces at birth -- that's the size of a half a stick of butter.
River otters are one of the few species that exhibit a phenomenon called delayed implantation. That means the otters breed in the spring, but the fertilized egg doesn't actually implant until fall.
