Rat snakes are certainly friends in the garden and they reside in every state of the Appalachias.
The adults can have some color variations, but typically the black rat snake is black with some white coloration between the scales. Gray rat snakes can potentially be mistaken for copperheads with their varied pale to dark gray coloring marked with a pattern of dark gray or brown blotches. Yellow rat snakes can resemble large garter snakes with four dark stripes running the length of a yellow, olive, or orange body. Adult rat snakes can reach a length of 6′.
If you find a smaller snake with a pale gray body, a pattern of dark gray blotches, and a checkered underbelly, it is likely the juvenile for any of the above rat snakes. Again, some people may mistake these snakes for copperheads, but young copperheads have a brown/copper coloration with no checkered underbelly and a brilliant yellow tip to their tail.
All rat snakes eat… rats… as well as other small animals including garden pests such as voles. They frequently enter the crawl space underneath houses to munch on the mice they find there. If you are finding rat snakes in your yard it is likely you are the host to a very healthy ecosystem.