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Today on Animal Fact Files we’re discussing shrews. While they may look like mice, shrews are not rodents. They're more closely related to moles and hedgehogs. There are also some species commonly called "shrew", such as the elephant shrew, that aren't part of the "true" shrew family. There are over 300 living species of true shrews making them one of the most species rich mammalian families on earth! Shrews also boast the smallest living terrestrial mammal: the white-toothed little shrew. This tiny shrew weighs less than an ounce (28g) and measures 3 inches (7.6cm) in length including its tail. On average shrews are about four ounces (113g) in weight and seven inches (18cm) long including their tail, but not all shrews have a long tail. Some have almost no tail to speak of! It can also be difficult to tell male and female shrews apart. A male shrew's testicles are retained inside the body, so they don't provide a clear external distinction as they do in other mammals.

Shrews live in Africa, Eurasia, North and Central America, the north western tip of South America, and some oceanic islands where they've been introduced. Their body shape can depend on where they live. Some shrews are semi-aquatic and have small, skin covered eyes or webbed feet. Others spend their time in tropical vines and have long limbs for grasping. Some are burrowers with small eyes, ears, and tails. Shrews can be found in forests, grasslands, deserts, swamps, and more, though they tend to prefer areas with moisture. In fact, some shrew species have thick hairs on their feet that allow them to walk on water!

They use their prehensile snout for sniffing out prey. Shrews are primarily insectivores eating insects and other invertebrates, but they also consume mushrooms, small vertebrates, and seeds. They have forward facing incisors for holding prey while they eat. Some are also venomous. A trait rare in mammals, some shrew species have toxic saliva that flows into a wound via grooves on the teeth and envenomates prey - not unlike a Komodo dragon!  In turn, these mammals are eaten by birds of prey, snakes, foxes, coyotes, weasels, trout, and more, though one of their greatest threats is tooth wear. Shrews lose their baby teeth before they're even born, so they only get one set to use throughout their entire lives. Many die due to starvation because they simply can't use their worn down teeth.

Shrews live life in the fast lane. A single shrew can eat more than its body weight in a single day. If a shrew goes even a few hours without eating, it will die. So they're active during the day and night and constantly on the move for their next meal. Even their reproduction is quick. It takes only a few weeks for shrews to reach reproductive maturity - about six weeks for females and twelve for males depending on the species. They mate and produce multiple litters of two to ten babies each year with most species slowing their reproduction in colder months. Shrews don't hibernate but they can enter states of low activity during the coldest parts of the year. Gestation in shrews takes about twenty days and the young leave their mother's care within a month's time. Most shrews only live about a year, but some can reach three years of age.

Like bats, some shrews are believed to use echolocation to navigate their environment. Supposedly, they also smell foul due to their musk which some describe as akin to a skunk's scent!

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