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The shrew is a tiny animal that looks similar to a small mouse. With their small size, generally between 3-5 inches in length, they do not look dangerous. However, I have been doing a lot of research into shrews recently and was surprised at how dangerous they can be.

Shrews can be dangerous to other small animals due to their sharp teeth. Shrews inject venom into their prey, paralyzing them. This venom is not dangerous to humans. However, the bite may cause swelling and pain for a few days. Always make sure to seek medical attention if bitten.

Although small, these creatures can pack a punch. There are over 387 species of shrews worldwide, but only three live in North America. 

The largest shrew species in North America is the northern short-tailed shrew. The least shrew is the smallest species found in North America. They grow to about 3 inches long and have a long pointed snout and a tail. 

The most common species in the United States is the Northern short-tailed shrew, found in almost all U.S. and large numbers on the East Coast.


Are Shrews Dangerous To Humans? 

Shrews produce venom, but this venom is not dangerous to us. A shrew will have no intention to attack a human. Shrews will generally run away and avoid any conflict with a human. However, if a shrew is cornered, it may bite you to get a chance to escape.

There are very few cases of shrews attacking human beings. However, if a shrew does bite you, there is no need to worry. The venom may be extremely dangerous to small animals, but not to us. 

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While shrew venom is not life-threatening, a bite from a shrew can result in extreme pain and swelling to the affected location. The pain and swelling will go away after a few days. However, as with all animal bites, the best advice is to seek medical attention immediately.

Shrews are wild animals that often carry bacteria and can also carry rabies. To avoid any further complications, get the wound treated by a doctor.

The shrew will only act in self-defense, so try to avoid confrontation with them. If you find them in the woods, do not disturb them.

Shrews try to stay away from people and do not generally invade homes. If conditions out in the wild are unfavorable, they may come inside your home, shed, barn, or garage. As shrews have a high metabolism, they eat a lot every day. They may attack chickens, pet rats, or rabbits to feed.

How to Recognize a Shrew? (To Avoid Getting Bitten)

Shrews are not rodents but are in their own family of Soricidae. They are solitary creatures, unlike mice. They can be recognized by a long snout and a pungent smell. They usually measure 3-5 inches in length and have small eyes and grey fur. They have small but sharp teeth with dark pigmentation at the tip.

Because shrews are tiny like mice, people do get them easily confused. Some people pick them up, thinking they are a mouse, and then the shrew bites them. This article has some great photos to help you identify them.

Want to know more about shrews.  Here are 101 facts I have put together for you.

Are Shrews Dangerous to Pets? 

Shrews are fierce predators and release venom when hunting or defending. Larger animals like cats and dogs are not affected by the amount of venom a shrew can inject. However, a bite can get infected, and venom injection can be excruciating. If you believe a shrew has bitten your pet, please take them to see a vet as soon as possible.

Cats and dogs may attack shrews. There are even instances where they have eaten shrews. Shrews are not considered a danger to pets because of their small size and the amount of venom.

They may attack small animals or those slightly larger than themselves. However, it is unlikely that most dogs and cats are at risk.

You should not encourage encounters between shrews and any of your pets. Like any other animal, the shrew will still try to fight for its life, scratching, biting, and clawing at your pet. The bite may not be dangerous, but it can be a source of bacteria and infections.


Are Shrews Aggressive? 

Shrews are territorial animals and can be highly aggressive towards other shrews and intruders. They are not aggressive to humans due to their small size.

They have adapted well to living in various habitats and like plenty of vegetation and ground cover to dig burrows.  They live in forests, swampy areas, gardens and fields, and woodlands and will use these areas to build their nest. Once they find the right place to nest, they will defend that territory fiercely and sometimes to death. 

Shrews mark their territories using a strong scent from their bodies. However, their primary weapon against intruders and predators is their sharp teeth and venom.  

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Shrews are unlike most mammals, as some species are venomous. There are grooves in their teeth, and the venom is injected into their prey through the grooves. The venom is potent, with the American short-tailed shrew’s venom glands sufficient to kill two hundred mice. 

Shrews use their teeth and venom to capture and kill their prey. The toxin is used for hunting but also for defense when faced with an enemy or intruder. 


The shrew has a gland in the mouth that releases venom when biting another animal. The venom does not immediately kill but will paralyze the animal. If it’s only an intruder to its territory, the shrew will leave it to die. If it is prey, the shrew will then eat the paralyzed animal. Their diet comprises mice, birds, frogs, salamanders, and other shrews.  

When disturbed, shrews are usually not quick to attack. However, if they have no other choice, this small animal will fight to the death.

Are Shrews Poisonous? 

Shrews do not produce poison, but they do bite and will inject venom. There is a big difference between venom and poison.  

Poisonous animals and insects produce poison as a defense mechanism when attacked or touched. Animals like shrews and snakes will bite and release venom into the wound. This helps them when hunting or defending themselves, their families, and their territories.