Marta8a that was a great link you posted. I took the link back to the main page and went throught all the snakes it listed. I bookmarked it for future use. It will come in handy the next time someone brings in a snake to be ID. I really enjoy reading everyone's comments about snakes. It is always amusing to hear what people think about snakes. Most people don't want to know they have snakes in their yards, but there are small snakes everywhere. Some of the smaller ones can pass for earth worms, if you don't pay close attention. I see a lot of snakes, people bring into my office to ask what they are. Almost all of them are harmless grass snakes and a lot are dead. It really excites people when I pick one up and look it over. I always take the live ones out back of my office and turn them loose in the flower beds. In the last 15 years, I have yet to see a poisonous snake brought into the office. Oh, and yes I take care of the beds so its not a problem that the snakes are there. I very rarely see one again.

Rat snakes eat rats too. "The presence of this snake in any setting near human habitation is a strong indicator that rodents such as rats and mice are also in the vicinity. These snakes are effective and efficient predators of disease spreading rodents. Diseases such as the plague and Hantavirus can be fatal to humans and have been identified from rodent nest in the Tarrant County. Fortunately, snakes are immune to these and do not transmit the illnesses to people. Asides from disease, rats and mice are responsible for damage to buildings, crops, and homes. Because of the benefit this snake serves, it should not be killed or molested." Here is a link that might be useful: Texas rat snake. Scroll down for photos ...

Let me think... Green Treefrog Gray Treefrog Spring Peeper Blanchards Cricket Frog Western Chorus Frog Bullfrog Green frog Bronze Frog Northern Leopard Frog (heard) Southern Leopard Frog American Toad Dwarf American Toad Fowlers Toad Blue Spotted Salamander Tiger Salamander Spotted Salamander Smallmouth Salamander Marbled Salamander Mole Salamander Longtail Salamander Cave Salamander Eastern Zigzag Salamander Southern Redback Salamander Northern Slimy Salamander Western Slimy Salamander Common Snapping Turtle Midland Painted Turtle Southern Painted Turtle Common Map Turtle Red Eared Slider Blanding's Turtle Eastern Collered Lizard Northern Fence Lizard Southern Coal Skink Five Lined Skink Broad-headed Skink Ground Skink Western Worm Snake Midwest Worm Snake Southern Black Racer Northern Ringneck Snake Mississippi Ringneck Snake Prairie Ringneck Snake Black Ratsnake Western Fox Snake Eastern Hognose Snake Speckled Kingsnake Black Kingsnake Yellowbelly Watern Snake Midland Water Snake Northern Water Snake Broad Banded Water Snake Queen Snake Midland Brown Snake Northern Redbelly Snake Eastern Garter Snake Chicago Garter Snake Lined Snake Western Cottonmouth Timber Rattlesnake Scott

Intergrade Black/Gray Rat Snakes look very similar to Texas Rat Snakes and can vary considerably in color and appearance from one specimen to the next. My guess is that your snakes are intergrade rat snakes.