Photos by Chris Brown

Scientific name: Crotalus helleri

Common name: Southern Pacific Rattlesnake

Size: 22-40 in (55-102 cm)

Distinguishing characters: A rattlesnake with grey, olive, or brown ground color and light-edged, darker diamonds on dorsum; blotches on sides dark, angular and also light-edged; light stripe from corner of mouth to eye; low-contrast dark tail rings, with terminal ring poorly defined and twice as wide; venter light yellow or cream with faint blotching; high elevation populations can be very dark or black dorsally, with little or no pattern definition.

Juveniles: Similar to adults, but with bright yellow-green tail.

Dimorphism: Male has a more stout tail than the female.

Similar species: Crotalus ruber: Has conspicuous black and white banded tail; usually tannish or reddish dorsal coloration

Additional notes: A nervous species that will aggressively defend itself when annoyed. VENOMOUS; don't handle or use extreme caution. Occurs in all habitat types in the focal area.