29 October 2025 In late August Jim Chapman and Pattie Relosky were exploring public land in northwestern Pennsylvania when they were surprised to see a snake basking by the trail. It was an endangered species they had heard of decades ago but never seen: an eastern massasauga rattlesnake (Sistrurus catenatus). Eastern massasaugas are one of … Continue reading Rare Sighting of a Rare Snake →
29 October 2025
In late August Jim Chapman and Pattie Relosky were exploring public land in northwestern Pennsylvania when they were surprised to see a snake basking by the trail. It was an endangered species they had heard of decades ago but never seen: an eastern massasauga rattlesnake (Sistrurus catenatus).
Eastern massasaugas are one of only three venomous snakes native to Pennsylvania. 125 years ago they lived in parts of Butler, Clarion, Venango, Mercer and Armstrong Counties (historic map below). Nowadays, there are only four small populations left out of 19 historic populations in Pennsylvania.
Jim and Pattie stood far away and used their binoculars to look at the snake. Jim zoomed his cellphone camera to take distant photos. The photo at top looks as if he was close but the image was cropped like this.
Fortunately the snake stayed frozen in place until Jim and Pattie left the area. Jim showed his photos to an expert who confirmed the snake’s identity and explained that this one was a pregnant female. Here’s why she was visible.
Pregnant females will choose sparsely vegetated dry areas to bask until they give birth to their young in August or early September. Females reach breeding age at four years and give birth to an average of six or seven young every other year.
— Western Pennsylvania Conservancy: Eastern massasauga rattlesnake
Amazing to me, massasaugas are ovoviviparous, meaning they carry their eggs inside them while the embryos develop and ‘hatch.’ The female gives birth to live young.
If you are lucky enough to see an eastern massasauga in Pennsylvania, keep in mind that it is endangered …
… and it can become dangerous. This species does freeze in place to avoid detection, but “if molested or injured the same snake will often strike repeatedly, with great accuracy.” — from Snakes of North America: Eastern and Central Regions by Alan Tennant, Lone Star Books, 2003.
p.s. Because they are endangered eastern massasaugas are well studied. Click here to see a young (small) snake being examined by a field biologist (photo from Wikimedia Commons).
