Shrews are small, insectivorous mammals often mistaken for rodents due to their size and habits. They belong to the order Eulipotyphla, which includes hedgehogs and moles, and are not related to mice. The shrew’s unique appearance and physical characteristics are tied to its specialized, predatory lifestyle. Accurate identification requires examining the specific details of its body shape, head structure, and sensory organs.
Overall Body Structure and Size
Shrews are among the smallest mammals, with many common species measuring two to three inches (5 to 8 cm) in body length. Their weight typically ranges from 5 to 14 grams. They possess a compact, cylindrical body shape supported by short, slender limbs.
The fur is dense, soft, and often described as having a velvety texture. Color commonly ranges from dark brown or gray on the back to lighter shades on the underside. Tail length varies significantly by species; some have tails less than 25% of their total body length, while others have proportionally longer tails.
The Unique Shrew Snout and Sensory Organs
The most striking feature is the long, pointed snout, which extends noticeably beyond the lower lip. This highly mobile proboscis constantly twitches, functioning as a primary sensory tool for foraging. The snout is covered with long, sensitive whiskers (vibrissae) that allow the shrew to detect prey and navigate its environment.
The shrew’s eyes are extremely small, often appearing like tiny, black beads partially obscured by dense fur. Similarly, their ears are small and rounded, sometimes nearly invisible, indicating that vision is a secondary sense. Shrews rely heavily on acute senses of smell, touch, and hearing, with some species using echolocation to orient themselves. This reliance drives their characteristic constant, frantic movement as they search for food.
Differentiating Shrews from Mice and Moles
Shrews are frequently confused with both mice and moles, but distinct physical markers aid identification. The most apparent difference between a shrew and a mouse is the head shape. Shrews possess a sharp, cone-like snout, while a mouse has a blunter, rounded face and prominent ears.
A mouse also typically has a long, thin, and often scaly tail, contrasting with the shrew’s shorter, thicker, and fur-covered tail. Differentiating a shrew from a mole requires looking at the forelimbs. Moles are adapted for subterranean life and possess massive, spade-like front paws rotated outward for digging. A shrew, which hunts above ground, has small, normal-sized front feet.
Shrews are generally smaller than moles. While a mole’s eyes and ears are often completely hidden beneath the fur, a shrew’s tiny eyes are usually still visible.