Overview
The Western Yellow-bellied Racer (Coluber constrictor mormon) is a lightning-fast, non-venomous diurnal serpent native to the sunny meadows and brushy foothills of the American West. Revered by herpetologists for its incredible agility and intense visual curiosity, this slender, smooth-scaled speedster frequently perches with its head elevated several inches above tall prairie grass like a periscope, scanning for fleeing grasshoppers and lizards.
Biology and Physical Characteristics
Coluber constrictor mormon has a slender, streamlined body covered in satiny, smooth unkeeled scales that give it a glossy sheen. Its dorsal coloration is a clean, uniform olive-green, slate-grey, or yellowish-brown, perfectly contrasted against a vibrant creamy-yellow to bright lemon-yellow belly and throat. It possesses enormous, round dark eyes with golden irises that provide acute daytime vision and long-distance depth perception.
Behavior and Ecology
An active visual pursuit hunter, the Yellow-bellied Racer hunts exclusively during the warmth of the day. Unlike constrictors (despite its scientific name), it does not kill prey by constriction; instead, it runs down grasshoppers, frogs, fence lizards, and voles at high speed, pinning them to the ground with a coil of its body and swallowing them immediately. When startled, it can sprint through dense brush at up to 4 mph, vanishing like green lightning.
Conservation and Human Impact
Assessed as Least Concern by the IUCN, the Western Yellow-bellied Racer is common and adaptable across western open landscapes. Highly beneficial to farmers and ranchers as a natural predator of agricultural rodent pests and pest grasshoppers, it thrives in rural rangelands and protected wildlife refuges.
Interesting Factoid
Despite its scientific name ‘constrictor,’ the Western Yellow-bellied Racer does not constrict its prey at all; it is a pursuit sprinter that simply chases down lizards and grasshoppers at high speed and swallows them whole.