Reptiles and Amphibians

Western Rattlesnake (Crotalis viridis) in Hetch Hetchy Valley. ©2008, James McGrew<br />
When alarmed or threatened, western rattlesnakes may coil, rattle, and then retreat to cover as soon as possible. However, this snake continued moving quickly and aggressively towards me after I came across it alongside the trail. Its aggressively erratic, quick movements coupled with rattling tail certainly rose my heart rate and made me worried even though I was at a relatively safe distance with a 200 mm lens. Rattlesnakes sense their environment by three primary means including vision of visible light with its eyes, sensing infrared light with the "pits" between the mouth and eyes, and chemical "smell" sensed with its long forked tongue. Well camouflaged and suited to hunting small rodents, the western rattlesnake is a common resident of the west coast middle and lower elevations and a vital part of the ecosystems.

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Western Rattlesnake (Crotalis viridis) in Hetch Hetchy Valley. ©2008, James McGrew
When alarmed or threatened, western rattlesnakes may coil, rattle, and then retreat to cover as soon as possible. However, this snake continued moving quickly and aggressively towards me after I came across it alongside the trail. Its aggressively erratic, quick movements coupled with rattling tail certainly rose my heart rate and made me worried even though I was at a relatively safe distance with a 200 mm lens. Rattlesnakes sense their environment by three primary means including vision of visible light with its eyes, sensing infrared light with the "pits" between the mouth and eyes, and chemical "smell" sensed with its long forked tongue. Well camouflaged and suited to hunting small rodents, the western rattlesnake is a common resident of the west coast middle and lower elevations and a vital part of the ecosystems.

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