Suncus (house musk shrews, <I>Suncus murinus</I>) are small mammals belong to the Sociridae, Eulipotyphla. In Japan, they were domesticated as laboratory animals in the 1970s and are the only widely used laboratory insectivore. In suncus, the stimulus of mating induces ovulation and the gestation period is 30 days. A well-known behavior between mother and pups is the coupling behavior known as caravanning. Their diet is high in protein and they have dentition similar to humans. Their digestive tract is short, thick, and lacks a cecum. They are vulnerable to fasting and water deprivation, agitation causes vomiting, and they have an incomplete body temperature maintenance mechanism (they are sensitive to cold), all of which are unique biological characteristics not found in laboratory mice and rats.