Note to visitors: there are no known sightings of rattlesnakes at Rancho Santa Ana Botanic Garden.

Carol Lerew
RSABG Volunteer, Nature Interpreter

Few words in the English language get our attention so quickly and completely as rattlesnake. We are fascinated by the danger and mystery surrounding this slithery reptile. Let’s explore some pit viper facts.

The western rattlesnake, Crotalus viridis, is one of 30 known species plus many subspecies of rattlesnake found in southern Canada, the United States and northern Mexico. It is the most prevalent rattlesnake found in the chaparral area. It often dens in rocky outcrops or in rodent burrows.

This snake has a wide triangular head, narrow neck and heavy body which can reach a little over four feet in length. It lacks eye lids and ears, depending on its forked tongue to detect taste, smell and touch. Its eyes have vertical pupils. Heat sensitive pits between the eyes and nostrils help it to detect prey. Fangs, folded back on the roof of the mouth, are released forward to bite prey or for self defense. Venom is squeezed from glands down through the hollow fangs and out through the holes in the tips. The venom attacks blood vessels and blood cells.

Coloration varies depending on habitat and subspecies. Generally, western rattlesnakes are light colored in hues of brown. Patches of dark brown are often seen along the back, becoming dark bands toward the tail. A color band can often be found back of the eye. Out in the open it is easily seen but is hard to detect curled up in scrub chaparral.

The rattle on the tail is a series of flattened interlocking horny segments that produces a buzzing noise when shaken vigorously. A new segment is added each time the snake sheds its skin, normally two to four times each year, although older snakes may shed only once a year.

Rattlesnakes are active from about April through October. During cooler weather they are active during the day, and when it gets hot, they hunt at night. Typically, prey consists of small mammals and some reptiles. Mating season occurs from April through June. As many as 25 young are born alive between August and October. Large numbers may overwinter together at a common den site.

Human and rattlesnake encounter stories abound. Many are simply scary meetings while others have ended in painful debilitating bites, though rarely in death. “The National Audubon Field Guide to California” suggests that if you encounter a rattler, freeze to let it withdraw, then step away.  If you are planning to be in an area where there are rattlesnakes, become knowledgeable about the latest first aid practices on how to treat snake bites.