My son was bitten by this snake
Thank you for your question. The snake in your photograph is a juvenile black ratsnake, scientific name Pantherophis obsoletus. It is a non-venomous species.
There is some discussion among taxonomists who determine appropriate names for species and subspecies. In your area, this snake is often referred to as an eastern ratsnake with the scientific name Pantherophis alleghaniensis.
This snake is found throughout or in portions of every eastern state except Maine and New Hampshire. They live in a variety of habitats, including forests, open areas and urban settings, especially if there are still sufficient numbers of trees.
This is one of the longest snakes we have in the eastern/southeastern United States. Typical length is 4-5 feet, but a maximum length of slightly over 8 feet have been recorded. They are excellent climbers.
They feed primarily on mice and rats, but also eat birds and young squirrels. They are also fond of chicken eggs.
Here's a link to the PA Herps web page for this species:
As the ratsnake gets older it becomes increasingly darker, turning almost completely black except for the underside of the front portion of the body which is white. The rest of the underside is usually some shade of grey. If you look closely at an adult, you can usually still make out remnants of the juvenile pattern, although some individuals are dark black.
If you're interested in learning more about snakes in your area, this is an excellent guide:
Gibbons, Whit. (2017). Snakes Of The Eastern United States. Athens: The University of Georgia Press.
I hope this answers your question, and thank you for contacting Ask an Expert.