The Eastern Yellowbelly Racer (Coluber constrictor flaviventris) is a long, lean, fast snake. The adults are usually olive grey-green with a yellow belly. The other ten subspecies may be black, brown, blue or green with a lighter color belly.
The juveniles however are remarkably different. They have a tan or cream colored body with brown, grey or reddish blotches along with small brown or reddish spots below the blotches. This pattern distinctly imitates the rattlesnake. This is an advantage unless they run into human predators who like to kill all rattlesnakes.
They go through an ontogenetic color and pattern change as they reach sexual maturity in one to two years. They have fairly wide, distinct heads with round snouts and large eyes with round pupils. Their tails are whip like, the anal plate is divided and the scales are smooth and arranged in 17 rows. They can reach 5 feet long but more commonly are 3 ½ feet long. They can live for over 10 years in the wild.
Racers are fast moving, diurnal snakes that actively hunt. Their prey consists of rodents, insects, frogs, toads, lizards, snakes, reptile eggs, birds and birds’ eggs. They are not constrictors, but they may use a loop or two of their coils to pin their prey to the ground as they position their mouth in order to swallow the prey whole.
The young in particular consume lots of soft bodied insects. Racers in turn are prey for a variety of hawks as well as falcons, skunks and badgers. They often use their speed to flee from potential predators.
Habitat And Territory
The habitats they utilize include grasslands, agricultural areas, marshes, sagebrush thickets, prairie, open woods and semi-arid areas. In grasslands they will often move with their heads above the grass to better observe their surroundings. Their range includes eastern Montana and Wyoming extending into the Dakotas and then south onto the central plains and down into central Texas.
During the winter months they hibernate and often share hibernacula with other species such as garter snakes, milk snakes, bull snakes and rattlesnakes. They regularly return to the same den year after year. Racers emerge from their winter hibernation when temperatures have risen sufficiently for them to be active.
Racers usually mate between April and June. Around a month later the female will lay from 4 to 25 rather granular feeling eggs in a hidden nest site such as an abandoned rodent burrow, hollow log, beneath rocks on even and loose soil. Incubation often lasts about two months. The 8 to 10” long young hatch around late August or in the early fall.
They are quick to bite if handled and sometimes will release a foul smelling musk from their cloaca. When cornered they may vibrate their tail in another rattlesnake imitation. They do not do well in captivity. But then not many species do.