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6 Species of Garter Snakes in Pennsylvania 

Garter snakes are a mostly-harmless type of snake that lives throughout much of the United States. They eat a variety of small prey, including frogs, worms, and sometimes mice. There are more than 30 species in the US, but 6 species of garter snakes that make themselves at home in Pennsylvania. This article takes a look at these species habitats, diets, and behavior.

Collage photo garter snakes in Pennsylvania
Collage photo garter snakes in Pennsylvania

6 Garter Snakes in Pennsylvania

1. Eastern Garter snake

Eastern garter snake
Eastern garter snake | image by Peter Paplanus via Flickr | CC BY-SA 2.0

Scientific name: Thamnophis sirtalis sirtalis

The Eastern Garter snake is a subspecies of the Common Garter snake, which lives across the United States in habitats as varied as deserts, coasts, and prairies. Eastern Garter snakes thrive in the forests and meadows that dominate Pennsylvania’s landscape.

This snake has a base color of olive green, but it can also be black or brown. Those scales are interspersed with occasional darker green patches of scales. Three yellow stripes run along the body’s length. They’re located along the spine and the left and right sides.

The average length they can grow to is 26 inches, but some Eastern Garter snakes grew to over 40 inches long! It’s a very adaptable snake species that nests in trash piles, old farmland, and outbuildings.

They’re commonly seen in community gardens in cities. Wherever they choose to bask, they usually have a convenient hiding place nearby. This snake slithers off right away if threatened instead of staying to fight.

Frogs, worms, and slugs are the Eastern Garter snake’s meals of choice. They’re opportunistic, meaning that they eat almost anything they have the opportunity to run into.

2. Shorthead Garter Snake

Shorthead garter snake
Shorthead garter snake | image by bobistraveling via Flickr | CC BY 2.0

Scientific name: Thamnophis brachystoma

Shorthead Garter Snakes are Pennsylvania natives. These snakes live only in the northeastern United States.

They spend most of their time underneath logs, rocks, or leaf litter that’s close by to open fields. Meadows can be naturally-occurring or fallow agricultural fields created by humans.

They are middling baskers that prefer to bask only when it’s cloudy. Compared to other snakes, they’re social. Scientists do not yet understand why groups of snakes congregate nearby each other.

Shorthead Garter Snakes’ sole food is earthworms. It takes advantage of exposed dirt in open fields and meadows to search for and attack vulnerable worms.

This snake measures between 10 and 22 inches long. Recognize them based on their olive-green colored scales and three yellowish stripes that run from head to tail.

3. Eastern Ribbon Snake

Eastern ribbon snake
Eastern ribbon snake | image by John J. Mosesso via Wikimedia Commons

Scientific name: Thamnophis sauritus sauritus 

The Eastern Ribbon Snakes are the most common subspecies of the Ribbon Snake. Because of that, some people call them the “Common Ribbon snake.”

It lives throughout most of the southeast, but some live as far north as New England and Pennsylvania. Within Pennsylvania, Eastern Ribbon snakes reside in the eastern half of the state.

It is great at swimming, so it usually lives, nests, and hunts for its prey around lakes and streams. Most of its diet consist of small fish and amphibians like frogs or salamanders.

Depending on how old the snake is, it could be anywhere from half a foot to almost two and a half feet long. It adjusts what it’s eating to how much prey it can swallow.

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Recognize Eastern Ribbon snakes thanks to the three stripes on their sides and back. They have a stripe on each side and a stripe on the spine from head to tail. When confronted, they usually hide instead of trying to bite the threat.

4. Common Garter Snake

Common garter snake
Common garter snake | image by Greg Schechter via Wikimedia Commons | CC BY 2.0

Scientific name: Thamnophis sirtalis 

The Common Garter snake is a native inhabitant of Pennsylvania, and a relative of another garter snake living in the state: the Eastern Garter Snake. Common Garter Snakes are dark olive-green or brown with three light yellow or white stripes along their sides and back. The top stripe starts start at the neck, while the side stripes melt into the light yellow belly.

Like most garter snakes, the Common Garter Snake is lithe and small. While a specimen can grow to reach over 4 feet long, most measure in at a little under 2 feet.

In Pennsylvania, they live in forests, fields, and riparian areas of all elevations. When it gets cold, Common Garter snakes hibernate together. Scientists call a snake burrow a “hibernacula.”

This snake is most active during the day when it is the warmest. They swim around ponds and slither along the shoreline to find tadpoles, frogs, and worms. Unlike other garter snake species, they will eat warm-blooded prey like mice or voles.

5. Ribbon Snake

Ribbon snake slithering
Ribbon snake slithering

Scientific name: Thamnophis sauritus

Ribbon Snakes are a species of garter snake that lives throughout most of the eastern United States. They aren’t venomous and don’t pose a threat to people, so don’t worry if you spot one on your next nature walk.

Use their stripes to tell them apart from other types of snakes. Ribbon snakes almost always have three yellow stripes; both of Pennsylvania’s Ribbon snake species have them.

It gets cold in Pennsylvania during the winter, so Ribbon snakes engage in a form of hibernation called brumation. Brumation is similar to hibernation, but the reptile brumating can wake up, drink water, and go back to sleep on a regular basis.

Water is the constricting factor for where Ribbon Snakes live. Since they are excellent swimmers, they leverage that ability to chase after frogs, toads, and fish. Ribbon snakes stick to cold-blooded animals; they do not eat any warm-blooded prey.

Some also live in Pennsylvania’s Appalachian mountains. The damp forests offer abundant moisture and a variety of hiding places under leaf litter and low-growing vegetation.

6. Northern Ribbon Snake

Northern ribbon snake
Northern ribbon snake | image by Jon Fife via Flickr | CC BY-ND 2.0

Scientific name: Thamnophis sauritus septentrionalis

Northern Ribbon Snakes are the second of four subspecies of Ribbon Snake. They have a northern range and live only in the northwestern corner of Pennsylvania. Their populations rely heavily on the Great Lakes, so their range is limited to the land around the shores of these bodies of water.

 Identify a Northern Ribbon Snake by way of its coloration. It’s a mostly-black snake with three white or light yellow stripes.

Like other garter snakes, each stripe is located on the left side, right side, or spine. It has a whitish belly and small white “half-moon” marks directly in front of each eye.

If you’re lucky enough to be in northwest Pennsylvania, poke around in low-lying places with lots of water. This snake enjoys water, can swim, and lives where there’s abundant freshwater. It eats aquatic wildlife – think frogs, small fish, and salamanders – and can grow up to 26 inches long.

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About Anna Lad

Anna is a wildlife biologist who graduated from Texas A&M in 2020. She enjoys studying and learning about wild birds and wildlife of all types.