Reptiles
Racer
Coluber constrictor · also called racer, North American racer, black racer
A racer is the snake you see for half a second before it is gone — a slim, alert, fast-moving hunter that flows through grass and old fields by day, head held up like a periscope, watching for anything that moves. Its scientific name says “constrictor”, but that is a mistake: the racer barely constricts at all.
Overview
The racer, Coluber constrictor, is a slender, fast, diurnal snake found from southern Canada to Guatemala in open country — prairie, old fields, grassy marshes, woodland edges. It is a visual hunter with a broad diet: insects, frogs, lizards, other snakes (including venomous ones), rodents, and birds’ eggs, mostly eaten alive without constriction.
Fast and misnamed
Racers reach about 5–6 km/h in bursts — a brisk walking pace, but combined with constant alertness and smooth continuous movement it makes them seem to vanish. The name “constrictor” is inaccurate: a racer just pins small prey under a loop of body and swallows it struggling.
Bluff and change
Cornered, a racer mimics a rattlesnake, buzzing its tail in dry leaves, rearing up, striking, and musking — pure bluff from a non-venomous snake. Young racers are heavily blotched and look so different from the plain adults that they were once thought a separate species; the pattern fades over the first year or two.
Status
Least Concern — common and widespread, though it loses habitat to intensive farming, dies heavily on roads because it ranges so widely, and is often killed by people fooled by its rattlesnake act. The blue racer is locally rare in the Great Lakes region.
Racer: common questions
Do racers actually constrict their prey?
Not really, despite the scientific name Coluber constrictor. A true constrictor throws several tight coils around prey and squeezes until it stops breathing. A racer, hunting fast-moving animals in the open, simply overpowers small prey with its jaws, sometimes pressing a struggling animal against the ground or under a loop of its body, and then swallows it alive. Larger or more dangerous prey is just held and worked down. The name was given long ago and has stuck even though the behaviour does not fit.
Are racers venomous or dangerous to people?
No. Racers have no venom and are not a danger to people or pets. What they do have is an intimidating defensive act, in that a cornered racer will rear up, shake its tail against dry leaves to mimic a rattlesnake, strike out repeatedly, and smear a foul musk, and if you grab one it will bite, leaving shallow scratches that bleed a little. It is all bluff and last-resort defence. Given any chance, a racer relies on its real defence, which is simply to race away at high speed into cover.
How fast can a racer move?
Fast for a snake, but slower than the name suggests. Measured top speeds are around 5 to 6 kilometres per hour, roughly a brisk human walk, in short bursts over open ground. What makes a racer seem so quick is its combination of a slender build, constant alertness, and the way it flows smoothly and continuously through grass and low vegetation without pausing, disappearing almost before you register it. It cannot outrun a person over distance, but it rarely needs to, because it is usually into a burrow or brush pile within a second or two.
Why do young racers look so different from adults?
Hatchling and juvenile racers are boldly marked with dark blotches or saddles on a pale grey or brownish background, a pattern that camouflages a small, vulnerable snake among leaf litter and broken light. As the racer grows over its first year or two, the blotches fade and merge and the snake takes on the plain adult colour of its region, whether that is glossy black, blue, tan, or olive. The change is so complete that early naturalists catalogued the young and the adults as separate species.