Know Your Local Snakes

Open through April 19 in the Academy’s Special Exhibits Gallery, Titanoboa: Monster Snake takes us back to the Paleocene, the lost world that followed the demise of the dinosaurs. You can check out a life-size model of this massive 60-million-year-old predator, crawl through a snake-sized tunnel, and get nose to nose with live snakes.

Special Exhibits Educator Mary Bailey wants us to understand that, while Titanoboa could perhaps take on a creature as massive as T. rex, most snakes are harmless and even afraid of us. Below, she helps us answer some common questions about what to do if you happen to meet a snake in your backyard, local park, or nearby campground.

Q: What do I do if I find a snake in the wild?

A: The best thing you can do is leave it alone. Most snakes will be scared and quickly slither away. If they are unable to escape, they will notify you of their presence by wiggling their tails, making fake “strikes” in your direction, or another method. Most snakes do not view humans as food, so it is unlikely that a snake will bite you if you do not try to pick up or handle it.

Q: What are some common snake species we might see around the Philadelphia area?

A: The Northern brown snake (Storeria dekayi), pictured above, is thin like a pencil and ranges from 3 to 10 inches long. It has two rows of small dark spots down its back. Believe it or not, it loves to hang out in cities like Philadelphia! The Northern brown snake likes to hide under rocks, logs, or other items that get warm and cozy in the sun. If you’re a gardener in Philadelphia, you’ve probably spotted one from time to time. The snake can bite, but it is not venomous. It may puff up if it feels threatened. It likes to eat slugs, so it may be beneficial to your garden!

In Philadelphia, you may spot a garter snake hiding in leaf litter or even in your basement. This snake tends to be black and tan or yellowish with a light stripe or checkerboard pattern running down its back. Unlike the Northern brown snake, the garter snake is active during the day as it hunts for worms and slugs. You might see it slither across a forest path, especially near the external limits of Philadelphia where there are fewer busy streets. Do not pick one up, or you may risk a bite.

Q: Are there venomous snakes nearby?

A: There are just two species of venomous snakes in the areas around Philadelphia: the Northern copperhead and the timber rattlesnake. The Northern copperhead has a thick, heavy body, a large and triangular head, and reddish-brown “saddles” shaped like hourglasses on its back.

The timber rattlesnake, which reaches about 3 to 5 feet when full grown, has a large head and dark, zig-zag bands across its body on a yellowish, grayish, or dark background. Some are almost completely black, and all have a distinctive rattle on the ends of their tails.

Like other venomous snakes, the Northern copperhead and timber rattlesnake have indentations on the side of the head between the eye and nostril and pupils that look like vertical slits (like those of a cat). These vertical slits can help you distinguish the Northern copperhead from two snakes commonly confused with it, the Eastern milk snake and the Northern water snake, both of which have round pupils.

Q: Do snakes carry rabies?

A: Rabies only affects mammals. Reptiles, amphibians, fish, birds, and insects do not get or carry rabies.

Be a Scientist

When you visit Titanoboa, examine the live snakes to find out more about their lives and habits. Try to answer the following questions, and then tell a staff person what you learned:

1. What does the snakes’ skin look like?

2. How are their pupils shaped?

3. Are they sleeping?

4. What are they eating?

5. What do they have in common with the model of Titanoboa, and how are they different?

The Pennsylvania Fish and Boat Commission has a good page to learn about the different snake species in Pennsylvania. 
New Jersey’s Department of Environmental Protection has information about snakes in that state.

This article originally appeared in the Academy’s member magazine, Academy Frontiers.

8 comments

  1. Looking closely at photos of Eastern rattlers, I don’t notice “pupils that look like vertical slits”, though I do see them in copperheads. Do the rattlers really have verticle pupils?

    1. Thanks for your question, Pat! Here’s a response from one of our experienced Academy educators:
      While timber rattlesnakes do have vertical pupils, it is completely understandable for the pupils to appear round in some photographs. A vertical pupil supports the ability of the snake to maintain some level of vision over a large range of brightness. Just as our pupils will dilate in dim or dark surroundings, so will the rattlesnakes. During dawn, dusk and night, the snakes pupil may appear almost round, while almost completely dilated. During the brighter daylight hours, the vertical slit will become much more prominent to prevent an “overload” of light from entering the eye.
      Take a careful look at the rattlesnake photos. If the pupils do not appear to be a vertical slit, they are most likely quite dilated, taking up 40-50% of the eye.
      The same applies to eastern diamondback rattlesnakes (if that is what you were referring to by “Eastern Rattlesnake”). However, their iris is also very dark, which makes it difficult to see where they pupil begins and ends. This may give the illusion of a very large pupil.

  2. Recently, during fishing the Neshaminy Creek, seen a snake approx 3″ in diameter 30″ long brown in color, under water, coiled next to a rock, it was approx 6″ deep. I disturbed it with the end of my fishing pole. It played sead first two pokes, then swam towards me and right between my legs, into the current. What kind of snake hides under water?

    1. Northern water snake. Is what you most likely saw. They are mostly a drab brown. They will lie submerged looking for fish or frogs to feed on. I have seen many in pennypack and even had them as pets 45years ago. They have 3 distinct behaviors. They will quickly flee. They will stand ground and bite. And oddly will docilely allow you to pick them up like a lifeless piece of rope.

  3. Recently, during fishing the Neshaminy Creek, seen a snake approx 3″ in diameter 30″ long brown in color, under water, coiled next to a rock, it was approx 6″ deep. I disturbed it with the end of my fishing pole. It played dead first two pokes, then swam towards me and right between my legs, into the current. What kind of snake hides under water?

  4. I seen a snake it was about 6inches long thin as a thread brown color pointed head like a baby copper head but it was very thin never seen ever thin as a crack

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