Are Shrews Dangerous?


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 extremely sharp teeth. Shrews also inject venom into their prey, paralyzing them.

Although small, these creatures can pack a punch. There are over 387 species of shrew in the world, but three in North America. 

The largest shrew species in North America is the northern short-tailed shrew. The second shrew is the least shrew. This is the smallest of all the species found in this region. 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 which is found in almost all parts of the US but found in large numbers on the East Coast.

Are Shrews Aggressive? 

Shrews are very territorial animals and extremely aggressive towards other shrews and intruders. They have adapted well to living in various habitats. Shrews can live anywhere with plenty of vegetation and ground cover for them to dig burrows.  


They live on forests, swampy areas, gardens and fields and woodlands. They will use this area to make their nest. Once they find the right place to nest, they will defend that territory fiercely. 

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

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Shrews are unlike most mammals as some species are venomous. Unlike snakes which will inject venom into their prey through their fangs, shrews use a different method.

In the tooth of a shrew, there are grooves, and through these grooves, the venom is injected into their victim. The venom is powerful, with the venom glands of the American short-tailed shrew sufficient to kill two hundred mice.  

Shrews use their teeth and venom to capture and kill their prey. The venom is meant for hunting purposes, but can also be used as its last line of defense when faced with an enemy or intruder. 


The shrew has a gland in the mouth that releases venom when the shrew bites another animal. The venom does not immediately kill but will paralyze the animal. In this case, if it’s only an intruder to its territory, the shrew will leave it to die. On other occasions, the shrew will then eat the paralyzed animal. Their diet comprises of 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.

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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 they are attacked or when they are touched. Venomous animals such as shrews will bite and release venom into the wound. This is usually the case when they are hunting, or when they are defending themselves and their territories. 


Shrews are not poisonous, but they are venomous. The shrew has glands inside the mouth that release the venom together with saliva whenever it bites, releasing the venom through grooves in the teeth.

Are Shrews Dangerous to Pets? 

Shrews are fierce predators and at times will attack small animals or those slightly larger than themselves. Venom from a shrew is lethal to small animals such as frogs, lizards or worms. The venom paralyzes the prey making it immobile and easy to eat. 

Larger animals like cats and dogs are not affected by the venom. However, a bite can get infected, and the injection of venom can be very painful. If you believe a shrew has bitten your pet, then please take them to see a vet as soon as possible.

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


You should not encourage encounters between shrews and any of your pets. Similar to any other animals, the tiny 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.

Can Shrews Kill Humans? 

Shrews produce venom, and for this reason, people are worried whether this venom can be dangerous to human beings. The venom is not life-threatening for human beings. 

The venom is used for hunting purposes and defending territories. A shrew will have no intention to attack a human. Most of the time, this little creature will simply run away and avoid any conflict with man. However, if a shrew is cornered, it may bite you to get a chance to run away. 

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 rarely to a large animal. 


While the 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 on its own after a few days. However, as with all animal bites, the best advice is to seek medical attention immediately.

Shrews are wild animals which often carry bacteria, and severe infections, including 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 any type of 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, then they may come indoors. As shrews have a high metabolism, they do eat a lot. They will attack chicken, pet rats or rabbits and can turn them into their next meal.

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

Because shrews are small like mice, people do get them easily confused. Some people will pick them up, thinking they are a mouse, and then get 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.

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Bryan Harding

Bryan has spent his whole life around animals. While loving all animals, Bryan is especially fond of mammals and has studied and worked with them around the world. Not only does Bryan share his knowledge and experience with our readers, but he also serves as owner, editor, and publisher of North American Mammals.

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