As soon as he stuck the needle into the newborn baby's heel, Dr. Yashuhiro Indo knew something was wrong. "I was thinking out loud, why does this baby not cry?'" said Dr. Indo, a pediatrician and molecular geneticist from Kumamoto University. There exists a small group of people who, like this baby, have never felt the unpleasantness of a shot, the sharp pain of a paper cut, or a sudden burn from a hot surface. These people are insensitive to pain and are said to have hereditary sensory and autonomic neuropathy (HSAN). One version of this disorder, called congenital insensitivity to pain with anhidrosis (CIPA), is an extremely rare disorder of the nervous system in which the body is insensitive to pain and temperature. The repercussions of this disease are devastating.

Overfishing threatens not just fish populations, but also the coral reefs that depend on seaweed eating fish to keep them healthy, according to a recent publication in Ecology Letters. Seaweed-eating fish, such as parrotfish and surgeonfish, are the natural weed control experts of coral reefs. But when the fish populations are reduced, the weeds grow larger,and the fish stop eating them.