On this Moment of Science, we talk about the social life of the naked mole rat.
For the longest time, scientists have thought that only particular species of insects were eusocial. But did you know that they have recently discovered that a certain mammal is eusocial? And it's the sausage with fangs, the mole rat.
A species of insect is eusocial if it meets these main criteria. Many adults, including various generations of them, live together as a colony. They cooperate in building the nest and caring for the young. And there is some form of a reproductive hierarchy. This usually means there is a single queen who births all of the colony's offspring. Bees, ants, wasps, and termites are all examples of eusocial critters.
For a creature to be considered eusocial there should be some permanent physical trait that distinguishes castes of the colony from one another. For instance, the queen ant has wings, but the worker ants do not. In the case of the mole rat, the queen has specialized vertebrae that make her body longer than her cohorts. The extra length allows her to fit through the narrow tunnels of the home despite carrying up to twenty-seven fetuses at a time.