From Ohio History Central
The black rat snake (Elaphe obsoleta obsoleta) is the largest species of snake in Ohio. It can reach lengths of up to eight feet, averaging 42 - 72 inches. It is black with a faint gray or brown checkerboard pattern and white between its scales. They are native to most of Ohio. The black rat snakes habitat includes forests, farmlands, and old fields, where they find prey, including small rodents, birds and eggs.
It is an excellent climber, often going up trees or rafters to raid birds' nests of eggs and young. It is a constrictor.
When captured, they will release a very foul odor from scent glands.
Black rat snakes breed between April and June. During this time the female will lay 5-30 eggs (10-14 average).
During the spring and fall, the black rat snake is diurnal, but becomes nocturnal during the hot summer months. Like all reptiles, it is cold blooded.
Rat snakes will hibernate with other snake of different species including the timber rattlesnake and copperhead. There is a myth that in times of danger the black rat will steer, or "pilot", these venomous snakes to safety. Although this is completely false, it is also known as the Pilot Snake.
It is one of the most beneficial predators in Ohio. It excels in controlling rodent populations. Unfortunately because it often lives close to humans, it is the most frequently killed species of snake. This is because of its large size and a general human fear toward all snakes.
If left alone, it can live up to twenty years.