Get Into Nature: When green snakes turn blue

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Last week on a gravel road less than a mile from home, something long, thin, and blue caught my eye. It was a DOR (dead on road) smooth green snake. Tire tracks left no doubt as to the cause of death.

Two species of green snakes occur in the U.S. The smooth green snake inhabits the northern Midwest east to New England. The rough green snake occurs south of the smooth green snake's range, though there is some overlap in their distributions.

The rough/smooth designation refers to the scales that cover these snakes' bodies. The rough green snake's scales are keeled -- a ridge runs along the middle of each scale. The smooth green snake's scales lack a keel and thus are smooth. They also differ considerably in size. A rough green snake can exceed 36 inches in length, while the smooth species tops out at about 22 inches.

Both species are slender, bright green above, and completely harmless to humans. Rough green snakes prefer dense brushy habitat where they spend much of their time sunning and hunting amidst the branches of small shrubs. Smooth green snakes climb less frequently than their counterparts. They prefer meadows and grassy areas, including lawns, and can often be found under flat rocks and slabs of bark.

The reason that this green snake was blue is that it was dead. Shortly after death, green snakes turn blue. The yellow pigment, which combines with a blue pigment to make the snake's skin green in life, breaks down quickly after death. Only the blue pigment remains, so the snake's body changes color shortly after death.

Green snakes mate in June or July and usually lay their eggs in a depression under a flat rock. Three to seven capsule-shaped eggs, each about 3/4 inch long, incubate under the summer sun for four to 24 days. Incubation is brief because embryonic development begins while the eggs are still in the female's body. Hatching usually takes place in late August, so be alert for young snakes, especially when mowing the grass. Green snakes are beautiful, harmless and beneficial creatures.

Scott Shalaway is a biologist and author. His other weekly Post-Gazette column, "Wildlife," runs Sundays on the outdoors page in Sports. He can be reached at or RD 5, Cameron, WV 26033.


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