Most typically the dorsum (back) of this species is solid black and the venter (belly) is gray along most of its body length. The belly has a black and white checkerboard pattern. In young individuals, the light spots form crossbars along the back.

Sexual Dimorphism There may also be a series of white spots and speckles running along its sides.

Most are about 3½ feet long, although …

This snake looks much like the black rat snake, with a black body and white chin.

The gray belly coloration changes into a solid white at the throat.

The milksnake is a true constrictor. The speckled kingsnake is usually found in the central to southern United States and can reach 48 inches in length. However, black racers are usually smaller, and tend to have more white markings than rat snakes. The ground color is generally black or dark brown. Their diets consist of small mammals, insects, birds and other snakes. A Y-shaped or V-shaped light-colored blotch is usually present on the nape of the neck. Neither snake is venomous.

A black snake with white spots could be either a speckled kingsnake or a juvenile black racer. A medium to large, shiny black snake covered with small yellow spots. There is one thing that I know for sure that neither white snakes are venomous nor poisonous.

Speckled kingsnakes are easily identifiable as they are black with white spots or sometimes yellow spots. The black racer is found in the southern United States; juveniles can be about 6 inches long. This nervous snake will readily bite … The belly is yellowish with some irregular or rectangular black markings. A white or yellow spot in the center of most of the scales makes it look speckled. But as you referred it as black with white belly you may want to check this article as it cover the whole topic in details - Are Black Racer Snakes Poisonous? Juveniles are white to gray with brown or black spots.