Insectivores: Insectivora

These active little mammals prefer to remain out of sight, whether that is underground in tunnels, beneath leaf litter or brush piles, under rocks, or in some species, in the water. Typically nocturnal, active at night, although a few are active during the day. Insectivores have poor eyesight and they must rely on other senses. Sensory hairs, which are located on various parts of their bodies, heighten their sense of touch and make them extremely sensitive to their surroundings. Their hearing is also good, and the animals communicate with others of their own species and with other animals through a variety of squeaks, hisses, whistles, and buzzes. Insectivores have a keen sense of smell, which is important in locating and identifying prey, picking up the scent markings that border the territories of other insectivores, and in finding mates during the reproductive season. The moles and desmans have sensory receptors called Elmer's organs on their snouts, to identify and possibly to locate food items.

Insectivores' best defense against predators, animals that hunt them for food, is to remain hidden, so that predators are more likely to overlook them. Some, however, use other defense tactics. Hedgehogs, for example, can erect their spines to present an intimidating barrier to attacker. Some shrews and solenodons actually produce venom that they transfer with their bites in order to capture prey. Many species, especially shrews, will also attack members of their own species—not for food, but to protect territory. When placed in a confined space, shrews will typically charge one another, sometimes locking together and inflicting tearing bites until one dies.

Insectivores are typically active all year long, even in climates where temperatures in the winter drop below freezing. In colder areas of North America, for example, shrews are sometimes seen scurrying across the snow. A few, like some hedgehogs and tenrecs, hibernate, a dormant state where the animal does not eat or pass wastes, or go into a hibernation-like state when temperatures dip too low or when food becomes scarce.

For many insectivores, details about their reproductive behavior and their early development are unavailable. In general, however, individual insectivores remain alone all year, except during the breeding season. Even then, males and females come together for a very short time, and the male leaves the female well before she has her offspring. Depending on the species, an insectivore may mate once a year with many offspring, as the tenrecs do, or several times a year with fewer offspring per litter, which is common in many moles. Often the young of several nearby females will have the same father. The young of all species are born fully developed, with some becoming independent of their mothers within a few weeks, while others rely on their mother for food and protection for several months. In an unusual display of mother-and-child interplay, the mother in a few shrew species will lead the family in a caravan, with one youngster gripping the tip of her tail with its teeth. A second youngster does the same to the first youngster and on down the line, until the entire three to seven member family is all linked together in a row.

Most insectivores live only about a year, but a few, like the solenodons, may live several years in the wild.