Variation across North America: The Racers

Last week I posted pictures showing the differences in color pattern between Ringneck Snakes from New York vs. California. There are a number of other North American reptiles and amphibians that also show wonderful variation in color pattern, shape and behavior across the continent. Racers (Coluber constrictor) are found across the United States and parts of southern Canada from the Atlantic to the Pacific. The considerable geographic variation within this species has led to biologists describing eleven different subspecies. The pictures below illustrate the variation in coloration among the geographic variants of Racers.

The Blue Racer (Coluber constrictor foxii) is found in some of the states surrounding the southern edge of the Great Lakes, including Ohio, Michigan, Indiana, Illinois, and Wisconsin. The individual shown here was seen in southeastern Michigan:
Blue Racer

The Western Yellow-Bellied Racer (Coluber constrictor mormon) has a large geographic range, from southern California to southern British Columbia, and from the Pacific coast to Colorado and Montana. The individual shown here was seen in California’s Coast Range, near Lake Berryessa:
Yellow Bellied Racer

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