Rat Snakes can be seen in different colours in different countries depending on its surroundings and environment to blend in and make hunting easier
Grey rat snakes are the largest snake in Canada, can grow up to 7 feet in length. They are grey with dark gray blotches on their backs and bellies but fade away overtime
It wouldn't suit if there was a yellow rat snake in the middle of grassland, the yellow snake will stand out more than the green snake. Therefore, it would be better for the green snake to live in grasslands.
In green meadows of land, the snake will be a green colour to camouflage in the ground
And in savannah conditions, they will usually be a yellow colour to blend in.
Yellow rat snakes are a combination of eastern rat snake and black rat snake with yellow or orange colouring.