These Tiny Animals Form High-Speed Trains for Survival

While furry critters scurrying around your yard can be alarming, there is something so endearing about a shrew train that you can’t help but smile as you watch them. This fascinating YouTube clip shows a train of five shrews racing across the grass after being disturbed by someone mowing their lawn. The leader doesn’t seem to have the best sense of direction and even doubles back at one point, rejoining the train midway! This is typical behavior for shrews, so let’s explore why and how they do it.

What Are Shrews?

Shrews are mole-like mammals belonging to the Soricidae family. At a quick glance, you may confuse them for mice, but they are not rodents. They are actually more closely related to hedgehogs and moles. There are 487 known shrew species, and they are found almost all over the world except for Australia, New Zealand, and the polar regions. The masked shrew or common shrew (Sorex cinereus) is the most widely distributed shrew found in North America and the common shrew (Sorex araneus) is commonly found in the U.K. You are most likely to come across them in woodland, grassland, and hedgerows.

Why Do Shrews Form a Train?

When shrews travel in a train, this behavior is also called ‘caravanning’ and has even been described as a conga line. What you can see here is a mother shrew leading her family of babies to safety. These little creatures have many predators (including weasels, foxes, snakes, and domestic cats), so having to relocate is a common experience for them. Shrews can have litters of up to 10 pups, depending on the species, and moving that many offspring on your own requires strict organization.

It’s likely that this family’s nest has been disturbed, so they are relocating in a hurry. Mom shrew heads the line and each baby bites down on the tail of the shrew in front of it. They mustn’t let go because their lives (and the lives of their siblings behind them) depend on it.

The train is traveling at an impressive speed. Shrews are fizzing little balls of energy, and their heart beats at 500-1000 beats per minute. They have a supercharged metabolism, which means that they are constantly moving. The person filming this clip did well to keep up with them.

Why Is the Train Going Around in Circles?

Shrews are roughly the same size as a mouse but their distinguishing feature is their long nose. In the clip you can see the mother shrew thrusting it in the air. This is because she has very poor eyesight but a superb sense of smell. The whiskers around her elongated nose are also highly sensitive; they are known as vibrissae. Her nose is also flexible, and you can see her frantically using it to get information about her surroundings. She is presumably trying to figure out the best direction to head in!