Shrews are small, common mammals often mistaken for mice due to their size and appearance. They possess long, pointed snouts and a high metabolism, requiring them to eat frequently. Many people wonder if shrews are venomous and pose a danger, given their predatory nature.
Shrew Venom: A Biological Reality
Some shrew species, like the Northern Short-tailed Shrew (Blarina brevicauda), are among the few mammals confirmed to be venomous. This venom, primarily a neurotoxin, is produced in their submaxillary glands. Its main purpose is to incapacitate prey, such as insects, worms, and small rodents, allowing shrews to paralyze larger prey for later consumption, a practice sometimes called “live hoarding.”
Unlike snakes, shrews do not have hollow fangs for venom injection. Instead, venom is delivered through grooves in their lower incisors. As the shrew bites and chews, venomous saliva flows along these grooves and enters the wound. While potent enough to paralyze or kill small animals, the venom’s effects on larger mammals, including humans, are mild. The specific toxin, blarina toxin (BLTX), affects the nervous system.
Impact of Shrew Bites on Humans
If a shrew bites, the primary concern for humans is the mechanical injury from its sharp teeth. The venom, while present, is not medically dangerous to humans, with effects typically mild and localized.
Symptoms of a venomous shrew bite are usually localized and temporary. These can include immediate pain, a stinging or burning sensation, redness, and swelling at the bite site. Some individuals might also experience itching or tingling. Severe or systemic reactions are extremely uncommon. Effects typically subside within a few days, often compared to the discomfort of a bee sting.
Handling Encounters with Shrews
It is advisable to avoid handling shrews or any wild animals, as they can bite in self-defense and may carry bacteria or diseases. If a shrew bite occurs, immediate first aid is important to minimize infection risk. Thoroughly wash the wound with soap and warm water for several minutes. After cleaning, apply an antiseptic solution and cover the bite with a clean bandage.
Seeking medical attention is recommended for any animal bite, particularly if the wound is deep, shows signs of infection like increased redness, pus, or worsening pain. Medical consultation is also prudent if the individual experiences an allergic reaction, such as hives or difficulty breathing, or if they are immunocompromised. While shrews are considered low-risk for rabies transmission, general precautions for wild animal bites should always be followed.