Ticks in Pennsylvania

American Dog Tick (Dermacentor variabilis) on human skin.
© Melinda Fawver/Shutterstock.com

Written by Brandi Allred

Published: June 8, 2022

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Ticks in Pennsylvania may start small, but they can expand up to ten times their original size when fully engorged on blood. Ticks start as eggs and are known as larvae when they hatch. Larval ticks are so small they’re almost impossible to see, but they can still bite. Once they’ve had one blood meal, the larvae fall off the host and molt into nymphs. The nymphs feed, then molt into adult ticks, the kind we’re most familiar with. These adults have eight legs and no eyes, and ticks can’t run or jump.

So, how do ticks in Pennsylvania find their way into our skin and our nightmares? Well, ticks come equipped with special senses that allow them to track down, and latch onto, blood-bearing creatures—like humans. Here, we’ll learn about the six most common types of ticks in Pennsylvania and how to identify them. Then, we’ll learn how to keep these tiny parasites off our bodies and away from our blood. 

The Ticks of Pennsylvania

1. Lone Star Tick

Lone Star Tick (Amblyomma americanum) on a white background.

The lone star tick has long mouthparts, which lead to deep bites.


Lone star ticks are easily recognized by the ‘lone star’ marking in the center of their backs. At least, females are easy to recognize. Male lone star ticks in Pennsylvania lack the lone star marking. Like females, males have red-brown bodies and large mouthparts. Instead of a white dot, they have dark brown mottling. 

Lone star ticks are the primary vector for human monocytic ehrlichiosis; they do not carry Lyme disease. These ticks feed primarily on white-tailed deer but will always bite humans or dogs if given a chance. They’re also known as cricket ticks, turkey ticks, or northeastern water ticks.

2. American Dog Tick

American dog tick isolated on white background.

Like all ticks, American dog ticks are obligate hematophages, which means they need only blood to survive.


American dog ticks are the largest ticks in Pennsylvania. They have distinct mahogany brown bodies and legs. Females have brown abdomens with mottled tan scuta (the round shields just behind the heads). Males have abdomens fully mottled with tan and brown.

American dog ticks are some of the most common ticks in Pennsylvania. They’re found in fields with tall grasses or dense underbrush and are most active in the spring and summer. These ticks are the main vector for Rocky Mountain spotted fever, which they transfer to humans through their bite. American dog ticks are common throughout the eastern United States, as well as the Pacific Coast.

3. Winter Tick

Winter tick

The winter tick has eight legs, each with a tiny claw on the end.


Winter ticks rarely bite humans, so they’re relatively unknown but extremely common. These ticks have light brown legs with tan and brown abdomens and small mouthparts. Unlike other ticks, they take only one host for their entire life cycle. As their name suggests, winter ticks in Pennsylvania are most active in the fall and winter. 

Winter ticks are small, but when they’ve had a blood meal, they can grow up to ¼ inch long. They feed on large mammals, like moose, elk, deer, bear, and coyotes. They’re most commonly encountered by hunters in the fall months. Winter ticks do not transmit Lyme disease or Rocky Mountain spotted fever.

4. Groundhog Tick

The Groundhog Tick

Like all ticks, groundhog ticks can go a very long time without eating.


Also known as the woodchuck tick, the groundhog tick is the closest in appearance to the deer tick. These ticks have light tan bodies and large mouthparts, with dark brown legs. They’re most likely to feed off small mammals, like groundhogs, badgers, foxes, squirrels, raccoons, dogs, and birds. They rarely bite humans and do not transmit Lyme disease. They can, however, transmit the Powassan virus.

5. Deer Tick

Two deer ticks isolated on white background.

Deer ticks have a characteristic black color on their legs.


These ticks are also known as black-legged ticks, thanks to the characteristic black color of their legs. Females have mahogany brown abdomens and black scuta, while males are uniformly dark brown. Their most characteristic features are their black legs and large mouthparts. Out of all the ticks in Pennsylvania, these are the only ones capable of transmitting Lyme disease.

Deer ticks feed mostly on white-tailed deer. Larvae and nymphs feed on reptiles, birds, mice, rats, and other small mammals. They’re also known as bear ticks and will bite humans and dogs if they get the chance. Deer ticks are most common in the spring and summer months.

6. Brown Dog Tick

Close-up of brown dog tick crawling on human skin.

When brown dog ticks feed, they increase their total weight by up to 600 times.


Brown dog ticks are the only ticks in Pennsylvania that live indoors. These ticks can be found anywhere there are human structures and canines. As their name suggests, brown dog ticks feed mostly on our canine companions. However, they will bite humans or other domestic animals if they get the chance.

Brown dog ticks have slender, medium brown bodies with small mouthparts. They do not transmit Lyme disease, but they can transfer canine-specific diseases to dogs.

How to Avoid Ticks in Pennsylvania

Ticks in Pennsylvania may spread any number of bacterial infections or diseases through their bites. Because of the risk of transmission, it’s best to avoid tick bites, if at all possible. Your first line of defense against ticks is a layer of clothing—ticks can’t bite through clothing, nor can they run or jump. You can also spray your clothing (not your skin) with insect repellant. And, if you’re planning any outdoor activities, be sure to stay out of dense underbrush, forest leaf litter, and tall grass. These are prime areas for ticks, particularly in the spring and fall months.

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About the Author

Brandi is a professional writer by day and a fiction writer by night. Her nonfiction work focuses on animals, nature, and conservation. She holds degrees in English and Anthropology, and spends her free time writing horror, scifi, and fantasy stories.

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