white-toothed shrews (Crocidura russula) on green backgroundBank vole (Clethrionomys glareolus)

In appearance mice and shrews resemble each other quite a lot. but that is where it stops. They are, essentially, two completely different types of mice. Or better said shrew are no mice. Voles (arvicolinae) and true mice (muridae) are modern rodents which feed mainly on plant roots and seeds. While shrews are primitive insectivores (like Mole, Hedgehog and bats), they are actually predators and don’t have anything to do with rodents at all.

 

Wild Wood mouse resting on the root of a tree on the forest floor with lush green vegetation

Wild Wood mouse resting on the root of a tree on the forest floor with lush green vegetation

 

Always hungry shrews

 

Because shrews belong to the primitive species of insectivores they have a quite inefficient metabolism. Therefore they need to eat a lot of prey to stay alive, sometimes more than their own body weight each day. Thus, they are always rarer than ordinary mice species, because there is simply not enough food for a lot of shrews. More than a few hours sleep is not possible, because then the stomach starts to rumble again. Ordinary mice species usually sleep all day until darkness falls in. This means that shrews must also hunt during the day to survive. But during the day there are many dangers; birds of prey, cats, crows, you name it. For this reason shrews always live in places with cover, so they are not easily seen. A dense garden, reeds, tall grass, tall herbs such as nettles and thistles, are all examples of suitable habitat.

Shrews are among the most primitive animals on planet earth. All modern mammals descend from these early insectivores

That weird water shrews

 

Besides the general types of shrew, like common shrew, white-toothed shrew and pygmy shrew, there is also the water shrew, which is a very special and rare animal. It is a sort of mini-otter which can dive very well and hunts underwater for dragonfly larvae, small fish and aquatic insects. Stiff hairs on the front and rear legs are a kind of flippers and a row of bristles on the tail acts like a rudder. While running on the shore, it jumps in the water with a plunge. Namely, they are so light that a jump is needed to get through the surface tension of the water! Only very healthy aquatic ecosystems, where everything is right, are suitable. Water shrew are very mobile. Along a mile of healthy ecosystem only about 15 water shrews can find enough habitat to live and eat. And that is very few. Even for a species of shrew. Therefore, the water shrew is an indicator species. As a predator it resides at the top of a food pyramid. So if the water shrew appears somewhere, the entire food pyramid below, also should be there. In that case we are dealing with a healthy, clean and well balanced ecosystem where we can find many different species of mice and other animals.

Water Shrew (Neomys fodiens) on a River BankDiving Neomys Fodiens, European Water shrew in natural aquatic habitat

Want to see more shrew and mouse photo’s? Take a look here.

Kijk hier voor de nederlandse versie.

 

 

Geeky Wood mouse (Apodemus sylvaticus) with curious cute brown eyes looking in the camera on white background

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