Here's an interesting story about efforts to capture, breed and reintroduce Chicago's last rattlesnakes. These snakes are small, 24-30 inches full grown, and very docile. Although their venomous bite is serious, it is not life threatening to humans. And, they don't always release venom with their bite. That depends on whether or not they think you're edible prey.
We still had these little guys in my old neighborhood, back 20 years ago. For Chicago readers, that was up by the old Glenview Naval Air Station. The snakes used to get killed by cars while crossing busy Willow Road traveling between the landfill on the north side to the air station on the south side of the street. The snake population was finished off by dense residential and commercial development that replaced the air station.
Read more: Snake Roundup.