Family of the Week: The Parasitic Shrews

This is a highly unusual family of mammals. They very closely resemble the true shrews that are around today. However, their lifestyle is very different from what we know of modern shrews. They are small animals, equipped with sharp teeth, and claws that are longer and more curved than they are in modern shrews. The eyes are somewhat larger. The ears in most species are small and round, as they are in modern shrews. The body is rather elongate, and the legs are short. The tail in most species is mouselike, covered in mostly very fine hair. They are diurnal animals and found mostly in bushy areas, where they have access to bower rat nests. The reason being is because these shrews are parasites of bower rats. Much like today's cuckoo birds, these shrews slip into the nests of bower rats and eat the newborn baby rats, and replace them with their own babies, to be raised unwittingly by the parent rats. The saliva of these shrews is specially designed to mimic the scent of the baby rodents as she cleans the babies up from their birthing sac, so they would in no way be detected as foreign babies to the parents. The shrews usually have about 4-5 babies in a birthing season. The mother shrew will sneak into the birthing cavern of a bower rat nest while the parents are away, have her babies, then eat 4 or 5 of the baby rats (depending entirely on how many babies she births), and move on, never to see her own babies again. These shrews are also designed to have their entire brood in a matter of seconds, rather than minutes or hours. This way, the entire parasitic process takes no more than a minute. Plenty of time for her to complete before she is detected by the bower rats.

Each particular species of these shrews uses a specific variety of bower rat as their host, depending on their range. Their birthing season coincides with that of the bower rat family, as does hours of activity. Aside from eating bower rat pups, these shrews are insectivorous. Despite the fact that these shrews do eat the baby rats, they do not feed on the adults. And only the females feed on the babies. Males are purely insect eaters. Favorite foods include earthworms, spiders, insects, grubs, scorpions, and centipedes. Night time is spent in an underground burrow. Outside of the breeding season, these shrews are strictly solitary animals. They are rather elusive animals that crawl along in the forest underbrush.

Because of their small size, these animals have numerous predators. Snakes, predatory bats and birds, mongooses, weasels, dogs, Deinognathids, and even larger shrews like some of the species of feather-footed shrews, will take these animals. They are sometimes even victimized by angry bower rat parents, who would kill them onsite, but not necessarily eat them.