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Tracks and Sign: Masked vs Short-tailed Shrew

Shrews are the smallest of PEI’s mammals, but what they lack in size they make up for in attitude! We have four species on the Island, with the Short-tailed Shrew (Blarina brevicaudata, left) and Masked Shrew (Sorex cinereus, right) being most common.

Although you might mistake them for mice, shrews aren’t even in the same family. They’re not rodents at all, but rather in the Soricidae Family, along with other insectivores such as moles and hedgehogs. Shrews have tiny eyes and poor vision, relying on echolocation, smell and their sensitive whiskers for navigation. Like the slime mold of my last post that inspired the cheesy cult classic “The Blob”, shrews have their own 1950s science-fiction movie: “The Killer Shrews”. Pro tip: don’t rely on Hollywood for your biological facts - follow my page instead! The Short-tailed Shrew is the largest of our species, but weighs just 20 grams on average (less than an ounce). It’s probably good that it’s so small, as this is our only venomous mammal. Short-tailed Shrews produce a toxin in their salivary glands that can paralyze animals as large as a Meadow Vole (Microtus pennsylvanicus). They’re no real threat to humans, though a bite will be painful and usually swell up. They live up to their fierce reputation, and you definitely don’t want to handle a live Short-tailed Shrew without gloves because you *will* be bitten! The Masked Shrew is one of our tiniest mammals, weighing less than five grams on average (less than 0.2 ounces), roughly the same as a hummingbird. Like hummingbirds, Masked Shrews have extremely fast metabolisms, and heart rates as high as 800 beats per minute. They must eat at least their own body weight in food daily, focussing on larvae, insects, spiders and even small salamanders and bird eggs. A Masked Shrew will starve to death in less than a day if deprived of food. In the days following Hurricane Fiona, shrews were the only animals I found to have been directly affected. I came across dozens of dead individuals - not enough to make me worry about the population, but enough to make me take note. It could be that the storm prevented them from feeding and those without enough stored food starved. Additionally, shrews live in underground dens and tunnels, some of which would have flooded during the intense rain. Their light body weight would have been no match for hurricane-strength winds if forced to the surface. Shrews are active year-round and common in forests, fields and coastal areas across PEI. They are very cool Island mammals!

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