The reproduction of shrews that inhabit temperate and Arctic regions is seasonal, while the reproduction of species in tropical regions is uninterrupted. A good example is the Eurasian common shrew that lives in the northern temperate zone, and individuals of this species usually do not begin to breed until the following year of birth. The breeding season begins in April, and females can give birth to up to 4 to 5 clutches of up to 11 cubs per clutch. More commonly, however, adult females give birth to 1 to 2 litters (4 to 8 cubs per litter) and then die. There are also deaths of adult males, so the population is dominated by immature individuals at the end of summer. The gestation period for this species is 20 days, while the lactation period is 23 days. The first estrus period of the breeding season in a population is synchronized, which results in the fact that all females mate over the course of a few days. It must have been a period of madness, because each female's estrus period lasted no more than a few hours; DNA analysis of offspring, mother, and possibly father did show that a female could mate with as many as 6 different males during a single estrus. The mating of captive shrews has been observed and the males will bite the back of the female's neck to mate. Female mating can be distinguished by bite marks, as white hairs will grow at the bite mark in the future.
The anal-licking behavior of the shrew. Some species, like the one in the picture, get important nutrients by licking the end of the rectum – when the rectum comes out of the anus for easy licking. The most studied species in the tropics is the Skunk. Like the Eurasian shrew, their mating is also unselected, and it has been observed that in 2 hours, a female mates with 8 males up to 278 times. The gestation period of the skunk is 30 days, and each litter usually produces 2 to 4 cubs. Like other shrews, pups are born naked and have no vision, but develop rapidly after birth. Skunk pups have the behavior of walking in groups. When they are mature enough to leave the nest, they will line up. Each bites the tail of the first one, and the first one bites the tail of the female skunk. They bite very firmly, lifting the female skunk while lifting the entire group of cubs without disconnecting from the middle.
Most shrews are solitary, and the unselected mating patterns most likely found in the Common Eurasian shrew and Skunk are common among them. Due to the high demand for food, some species of shrews guard their territory for life or for a period of time in their lives. This guarding behavior of the Eurasian common shrew will be evident during the winter months. Many shrews have only close contact during the fight, mating and nesting phases, yet at least one variegated skunk has been shown to be able to form a longer-term partnership. There are other kinds, and the interaction between individuals is even more. American small-eared shrews are thought to be more or less permanently settled, and that individuals of the common white-toothed shrews are crowded together in the winter because this may help maintain body temperature.
There are several species of shrews that dig tunnels that are the core of territorial defenses. Among them, the American short-tailed shrew, the American small-eared shrew, the Eurasian common shrew shrew, and the water shrew all have the behavior of digging holes. Observations of the rearing smoky shrew, flower-faced shrew, Tushi shrew and shrew shrew show that they do not dig holes. For the water shrew, the importance of the tunnel is that it can squeeze water out of the fur; for the common Eurasian shrew, the hole seems to play an important role in maintaining a good fur condition. In the rearing state, the Common Eurasian Shrew often stores food in tunnels. Tunnels also play an important role in avoiding predators, and often have more than one entrance. Shrews build nests covered with grass and other plant materials in a small chamber at the end of the tunnel, where they spend most of their sleep and rest.