The naked mole rat is unique in several ways. It is the only mammal that is cold blooded and has a very low metabolic and respiratory rate. It's naked skin does not have any pain transmitters, a useful feature for an animal that spends it life underground. It is eusocial or the has the highest level of animal social behavior such as those possessed by bees, ants and wasps. Mole rat colonies castes or specialized behavior groups, raise their young collectively, and have a queen responsible for breeding. Workers are sterile. Mole rats appear spry and healthy well into old age. They have a resistance to cancer apparently because of the abundant production of a natural sugary substance known as hyaluronan. Finally, although mole rats eat primarily tubers, they are known to be coprophaglc. Because of these achievements, Science named the mole rat, 2013 "Vertebrate of the Year".