The True Dangers of Creepy Crawly Critters

As outdoor areas become more urbanized, it’s easy to forget that we share these spaces with a wide variety of creep crawly critters. Enjoying the outdoors with your pet can be a fantastic bonding experience and a great way to keep them active. However, many pets are very curious in nature and have a strong drive to check out any animal slithering, sliding, or hopping by. Some of these animals can pose a serious risk to your pet’s health. Owner recognition is the first line of defense when it comes to protecting your animal while you experience the great outdoors together.


These slimy creatures can cause serious health risks if consumed or chewed on by your pet. Not all newts are harmful to household pets and farm animals, but there are two newt species that can be particularly dangerous upon ingestion. The Red-Spotted Newt located in eastern USA and the Rough-Skinned Newt located north of Francisco Bay, California can both secrete tetrodotoxin. Tetrodotoxin is an extremely potent poison found in the white fluid-like secretions that these newts exude. Consumption of either of these newt species can lead to progressive muscle paralysis, respiratory distress, and seizures. Treatment typically involves a rinsing the mouth, supportive measures provided by a veterinarian, and possible surgical removal of the newt if completely consumed.


Flatworms are commonly referred to as Hammerhead worms and are an invasive species from SE Asia that have spread across the USA. These worms are frequently found in suburban areas and garden centers where exotic plants are in abundance. Similar to newts, they also secrete the potent poison tetrodotoxin. However, many flatworms need to be consumed before posing a significant toxicity effect on your pet’s health.


There are four main species of concern when it comes to venomous snakes: Rattlesnakes, Copperhead Snakes, Cottonmouth Snakes, and Coral Snakes. Rattlesnake species are native in every state except Alaska and Maine and each type is capable of significant envenomation. The venom toxicity is highly variable depending on the species of Rattlesnake and the geographic variation in venom profiles. Clinical signs commonly associated with Rattlesnake bites include airway obstruction, skin swelling at the site of the bite, drooling, weakness, seizures, respiratory distress, diarrhea, and vomiting. The most effective treatment for Rattlesnake bites is antivenom. Copperhead and Cottonmouth Snakes are both pit vipers and are located throughout the USA. Copperhead and Cottonmouth envenomation’s produce very similar clinical signs to that of a Rattlesnake bite, but in general, are not as severe as those associated with Rattlesnake envenomation. However, local bite wound affects can be quite significant. Treatment for these bites also involves the use of antivenom. Coral snakes are found in southeastern USA and are poisonous to all animals, especially cats. Their venom contains neurotoxins that affect neuromuscular junctions resulting in drooling, incoordination, disorientation, respiratory distress, and paralysis. The best treatment is antivenom administered by a veterinarian.


Spiders can create a serious health risk for your pet if they are bitten by a venomous species. Luckily, most spider species are minimally or non-venomous. However, species to be aware of are the female Black Widow located throughout North America, the female Brown Widow located in southern and western USA, and the Brown Recluse spider located in southern USA. Female Black and Brown Widows can be very dangerous, because they have prominent venom glands and can deliver a large venom dose with their bite. The male spiders of this species rarely inflict significant venom with their bites due to their smaller fang size and the inability to effectively penetrate the skin barrier of humans and animals. If bitten by a female Widow spider, common clinical signs include muscle pain and redness at the site of the bite, weakness, tremors, seizures, and respiratory distress. Treatment for Widow spider bites includes anti-venom and supportive care provided by a veterinarian. There is a large range of variability when it comes to envenomation from the Brown Recluse spider, also known as the violin spider. The majority of bites from this species are insignificant, however the presence of clinical signs indicates significant envenomation. If significant envenomation has occurred, common clinical signs include skin necrosis at the site of the bite, fever, vomiting, and weakness. There is no antidote for Brown Recluse spider bites, but treatment includes fluid therapy and supportive care provided by a veterinarian.

Stay up to date and aware of the creepy crawly critters in your local area or anywhere that you may travel to with your pet. To help reduce the risk of an unfortunate encounter you should closely monitor your pet while it is outdoors, always keep your pet on a leash, and reduce any nose-to-nose contact your pet has with other outdoor animals. If your pet does come into contact with one of these species, take action immediately. Contact a veterinarian or Pet Poison Helpline® at 1-800-213-6680.


Written by:

Shiloh Walker, DVM student extern

University of Minnesota, Class of 2023