What kind of snake is this?

Question

First, we are located in Missouri. In between St. Louis and Cape Girardeau. St. Francois county to be precise.

We just walked outside and found this on the porch so we carried it off. Normally this wouldn't be a big deal, but we have a little one now and I didn't want to take any chances.

The snake, pictured below, was approximately 6 inches long. He seemed timid in nature, he didn't let us get very close to him before he started to slither away.

I assumed he was a juvenile black rat snake, from my highly deductive google searching, but I also know that snakes sometimes change color, shape and design as they get bigger. So I wanted to find out if my guess was correctly or completely mistaken. Thanks for you help!

Answer 1

Great find!

I'm pretty certain that is actually a Prairie Kingsnake (Lampropeltis calligaster - likely the subspecies L. c. calligaster). The biggest indicator to me are the two alternating rows of dark spots on sides, with some blotches fusing. They are distributed all over Missouri, although pretty rarely seen due to their microhabitat:

They tend to be fossorial, spending much of their time underground and out of sight. As a result, there is little known about the biology and status of these secretive snakes. Most [prairie] kingsnakes are observed hiding under boards or other debris or crossing roads on warm evenings.

I actually used to study herpetology in St. Louis, and we caught a few of these. The juveniles tend to have well defined spots that fade in time, although there is some degree of polymorphism here. Looks like yours is somewhere in between. See pictures below for reference.

Juvenile:

Adult:

Worth mentioning these snakes are nonvenomous, and typically docile.

Photo cred: Edward Prenzler