Venomous Snakes of Maryland

Snakes are an important part of healthy ecosystems. A 2013 study by University of Maryland researchers found that a single timber ​rattlesnake removed up to 4,500 ticks from the forest annually by consuming tick-carrying small mammals. This removal ultimately can decrease the spread of Lyme disease. Every day, snakes function as vital predators, as well as prey. Because of their importance, all snake species are protected in Maryland under the Nongame and Endangered Species Conservation Act.

Maryland is home to 27 species and sub-species of snakes, including two with medically significant venom, the copperhead and the timber rattlesnake.

Left picture of a Northern Copperhead and the right picture of a Timber Rattlesnake.
Eastern Copperhead by Linh Phu (left); Timber Rattlesnake by Scott Smith (right)


Snake venom is saliva with zootoxins designed to immobilize and digest prey, as well as for defense. Venom is injected by fangs and is stored in a duct. Venomous snakes can deliver dry bites (without venom) as a warning. The toxins in venom vary by species; therefore, different venom can produce different functions.


Chart showing the differences between venomous and non-venomous snakes. ​Interestingly enough, snake venom also has medical benefits. F​or example, copperhead venom has been found to be effe​ctive at attacking breast cancer cells, but not healthy cells. Other medical uses for venom include ​dissolving blood clots, fighting bronchial asthma, treating Parkinson’s disease, and treati​ng Alzheimer’s disease.​

Maryland’s Venomous Snakes

Several of Maryland’s snakes possess venom, but only the copperhead and the timber rattlesnake have medically significant venom known to cause adverse reactions in humans. These two species are pit vipers (Subfamily Crotalin​ae). Pit vipers are named for the heat seeking pit between each eye and nostril. Both of Maryland’s pit vipers should be treated with caution and should not be approached or handled. The graphic on the right, and the associated table below, show characteristics of pit vipers in Maryland versus other Maryland snakes.

Other Maryland Snake ID Characters Pit Viper ID Characters
1. Round pupils 1. Elliptical pupils
2. No sensory pit 1. Sensory pit between eye and nostril
3. Head slightly wider than neck* 1. Head much wider than neck*
4. Divided anal plate scale 2. Single anal plate scale**
5. Double row of scales on the underside of tail ** 3. Single scales on underside of tail**

* Some snake species, like eastern ratsnakes and northern watersnakes will flatten their heads when threatened to mimic pit vipers.
** These characteristics are helpful when examining shed snake skins.

Preventing Snake Bites

On average, Maryland Poison Control receives 100 snake bite cases each year, about half of which are due to bites from venomous snakes, mostly copperhead bites. Snake bites are serious and require expert evaluation and treatment. Below are some tips on how to avoid being bitten:

  1. Learn how to identify the copperhead and the timber rattlesnake.
  2. When hiking or camping, watch where you put your hands and feet. Be mindful of where you sit and where you place your sleeping bag.
  3. Wear suitable clothing when hiking, especially through tall grass or heavy brush. Long pants and heavy boots are usually best in tall grass and heavy brush.
  4. Avoid rock piles and stacks of old boards or wood in forested areas as snakes use these areas frequently, especially sunny areas with canopy gaps.
  5. Be careful working around brush piles or other debris. Use a rake or long handled tool to move brush, debris, or other material before picking it up.
  6. Never handle venomous snakes, alive or dead.
  7. Leave snakes alone. Many bites occur when people attempt to capture or kill venomous snakes.

If bitten by a venomous snake, immediately contact the Maryland Poison Center at 800-222-1222. The Maryland Poison Center is open 24 hours a day and is staffed by pharmacists or nurses who are specially trained and certified in emergency poisoning and overdose cases. Do not apply ice, a tourniquet, or make an incision around the wound as these methods do not work and may cause complications.

Living with Snakes

Snakes are a part of our natural world. If there is cover and food for snakes around your home, they will likely be present. Snakes will shy away from humans if given the chance, but they respond more to ground vibrations than sound. Their response to ground vibrations is often defensive when encountered. To deal with snakes, you can either learn to live with them or make your surroundings less enticing for snakes. To discourage snakes from your yard:

  1. Get rid of all mulch beds, mulch piles, firewood piles, and yard debris piles. Egg-laying snakes love these areas to nest in, and all snakes use these areas as escape cover from predators. While copperheads give live birth, these areas still provide them great cover and are an enticement.
  2. Get rid of anything that will be an attractant to small rodents (and thus to snakes which eat them, including copperheads), such as bird seed/bird feeder, pet food out of doors, garbage, etc.
  3. If you have any man-made ponds, water gardens, etc. that attract frogs and toads, these areas will also attract snakes that feed on them (water snakes, garter snakes, etc.). Water features with any aquatic vegetation in the wet areas or thick, low vegetation adjacent to it are particularly attractive. You would need to remove water gardens or make them very sterile looking.
  4. Get rid of all thick, low vegetation on your property, including flower beds, decorative shrubs, etc.
  5. Keep vegetable gardens weed free and do not plant any vegetables or fruits that create thick ground cover.
  6. Remove dense foundation plantings and any areas that provide thick cover around the foundation of your home.
  7. Keep your lawn mowed short.

Plants next to a house that can provide cover for snakes.
Dense foundation plantings can provide cover for snakes by Victoria Fee, licensed under CC BY-NC-ND

It’s important to note that even with taking the precautions above, there is no way to completely exclude snakes from outdoor areas. Snakes serve vital roles as predators, and only a small percentage of snakes in Maryland are venomous. It is important to familiarize yourself and your family about wildlife safety and identification.