Shrews are small mammals often mistaken for rodents like mice due to their similar size and appearance. However, shrews are not rodents; they belong to the order Eulipotyphla, making them more closely related to moles and hedgehogs. A distinguishing feature is their long, pointed snout, which sets them apart from blunt-nosed rodents. A common question about these tiny creatures is: do shrews burrow?
Shrew Habitats and Burrowing Behavior
Shrews do not construct extensive burrow systems of their own. Instead, these highly active mammals are opportunistic, often utilizing existing underground networks created by other animals. They frequently occupy abandoned tunnels dug by moles or voles, finding these existing pathways efficient for movement and shelter. Shrews also readily use natural crevices, spaces under fallen logs, dense vegetation, leaf litter, and rock piles as safe havens and hunting grounds.
This reliance on existing structures is linked to the shrew’s exceptionally high metabolic rate. Shrews have one of the highest metabolic rates among mammals, requiring them to consume a significant amount of food, often up to three times their body weight daily. This constant need for sustenance means they are almost continuously foraging for insects, worms, and other small invertebrates. Expending energy on digging complex burrows would be inefficient given their constant search for food.
They do not hibernate, remaining active year-round, which necessitates continuous feeding and efficient use of existing shelters. While they may dig small, shallow holes for foraging or to connect to existing pathways, these are not the extensive tunnels characteristic of true burrowing animals like moles.
Identifying Shrew Presence
Since shrews are not prominent burrowers, identifying their presence requires looking for subtle indications. Direct sightings are uncommon because shrews are secretive and spend much time concealed within dense cover or existing tunnels. One sign of their activity can be small, narrow runways they use through thick vegetation or beneath leaf litter.
Another indicator is their distinctive droppings. Shrew droppings are tiny, typically around 2 millimeters in diameter and 6 millimeters long, dark, and often have a curled or corkscrew shape. These droppings are frequently found in small piles and may carry a pungent, musky odor. Shrews are also quite vocal, emitting a variety of high-pitched sounds, including squeaks, chirps, and chattering, which can sometimes be heard during interactions. Some species even use a form of echolocation, emitting ultrasonic squeaks to navigate their environment.