A shrew is a tiny, mouse-like mammal and one of the smallest land creatures on Earth. Despite their size, shrews are intense predators known for their voracious appetites and relentless activity. The common question of whether shrews eat mice stems from confusion about their predatory nature and place in the animal kingdom. This article examines the shrew’s biological distinctions and its predatory relationship with mice.
Shrews are Not Rodents
Although shrews share a superficial resemblance to mice, they belong to a completely different biological classification. Shrews are members of the order Eulipotyphla (along with moles and hedgehogs), placing them in a distinct group separate from the order Rodentia (which contains mice, rats, and squirrels).
The difference is most clear in their anatomy, particularly their teeth. Rodents possess continuously growing, chisel-like incisors used primarily for gnawing on plant material and seeds. In contrast, shrews have sharp, spiky, and highly specialized teeth designed for seizing and shearing animal prey. This difference in dentition reflects a predator’s diet rather than that of a herbivore or omnivore.
Extreme Metabolism and Primary Diet
Shrews are characterized by an extremely high metabolic rate, driven by their tiny size and high surface-area-to-volume ratio. They rapidly lose body heat and must constantly replenish energy stores to survive. A shrew can perish from starvation if deprived of food for just a few hours.
To fuel this constant need, many shrew species must consume an amount of food equal to or even exceeding their own body weight every single day. The primary components of this diet are invertebrates, such as beetles, insect larvae, earthworms, and slugs. This focus on insects and other small, soft-bodied creatures establishes the baseline for the shrew’s predatory lifestyle.
Predation on Mice and Small Vertebrates
The question of whether shrews eat mice is answered by their predatory nature and metabolic demands. Yes, shrews prey upon mice and other small vertebrates when the opportunity arises. This predation is typically directed at vulnerable targets, such as newborn or injured mice, which a shrew can easily overpower.
The northern short-tailed shrew (Blarina brevicauda), for instance, is one species documented to attack and consume small rodents. While attacking a full-grown, healthy mouse is a high-risk endeavor for a tiny shrew, the prospect of a high-calorie meal outweighs the danger. They are also known to scavenge the carcasses of other small vertebrates, including small snakes and salamanders, if encountered.
Specialized Hunting Adaptations
Several shrew species possess adaptations that allow them to take down prey larger than themselves. Some shrews, such as the Eurasian water shrew and the northern short-tailed shrew, are among the few known venomous mammals. They deliver a neurotoxic venom through grooved incisor teeth, which can immobilize or kill smaller prey like mice or insects.
This venom allows the shrew to subdue a struggling victim or even “live hoard” food by paralyzing the animal and storing it for later consumption. Additionally, some genera, including Sorex and Blarina, employ a rudimentary form of echolocation. Unlike the precise sonar used by bats, the shrew’s high-frequency calls are primarily used for close-range spatial orientation, helping them navigate their dark, cluttered environments to locate their next meal.