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Rattlesnakes!

Living With Snakes
Bradford D. Hollingsworth, Ph.D., Curator of Herpetology

The winter storm cycle has officially come to an end and summer is here again. With each warming day, snakes become more active and encounters with people more frequent. San Diego and its surrounding areas have a tremendous snake diversity, with over 60 different species, ranging from small, secretive burrowers to large-bodied, dangerous rattlesnakes. In San Diego County 25 snake species have been documented. Of these, only four are hazardous to humans and their pets. All four of these are rattlesnakes, and the vast majority of bites occur when people try to handle these venomous reptiles.

The peak activity season for snakes occurs in late spring and early summer. The hot days and warmer nights bring snakes out of their retreats so they can start living their lives again. After all, this is the time of year when all of nature's creatures are on the move. Snake encounters become an exciting possibility and reports of snake activity flood the Museum.

The majority of snake sightings come from residents living near urban canyons or those in newly constructed developments. Other reports come from interested naturalists and hikers who spot snakes crossing the trails or speeding through the grass. San Diegans have a healthy appetite for knowledge, so along with the reports are a host of questions.

Most San Diegans simply want help identifying which species of snake was seen crawling through their woodpile. Others are more concerned. Luckily, most San Diegans already have a high regard for their native wildlife, so convincing them not to kill these animals is generally unnecessary. Yet the vast majority of people are looking for ways to prevent snake encounters from occurring in the first place.

A number of practical measures can be taken to decrease the chance of encountering a snake. Clear woodpiles and areas where rodents live. Possibly erect a wall around the perimeter of the property or a two- to three-foot high mesh fence partly buried into the ground. This is especially good advice for homes bordering native habitats. While even the best-planned fortresses can be entered, walls and fences will dramatically reduce the ability of rattlesnakes from entering into the yard. Other harmless snakes may not be deterred because of their propensity for climbing. There are no chemical deterrents known that are completely effective and long-lasting.

Of the four species of rattlesnakes, two are not commonly seen by San Diegans. The Sidewinder (Crotalus cerastes) is restricted to our deserts and the Speckled Rattlesnake (C . mitchellii) is more secretive, preferring rocky terrain. Most rattlesnake encounters involve the Red Diamond (C. exsul) and Western Rattlesnakes (C. viridis). Both are large-bodied, terrestrial snakes that prefer the same habitat prized by housing developers. As a result, homes are built in areas already occupied by these snakes. Families living along the margins of the development near open space often have the highest occurrence of snake encounters.

All snakes are beneficial to people in one way or another. Snakes are integral members of our ecosystem. Many species help control rodents and studies have shown that snakes significantly reduce rodent populations. Without snakes, rodent species would swell to carrying capacity and overwhelm the ecological balance. More importantly, snakes represent a pinnacle of evolutionary diversity. They are supreme hunters revered by cultures all over the world. People are intrigued with these animals.

Intrigue of nature is a human quality often overlooked. In the course of our daily lives, we often tune out the wilderness that surrounds us. Unfortunately, in many places, the wilderness has been sterilized by replacing it with manicured lawns and tree-lined roads. Little remains to remind us of nature's arousals. Even when we pass a coastal marsh or see a hawk flying overhead, our fascination about nature is hardly stimulated. These scenes blend into our daily consciousness and go unnoticed. We become anesthetized by familiarity.

A snake sunning itself on the pool deck is a completely different matter. Intrigue rushes back in. It is something to tell your friends about and it is the first subject discussed at the dinner table. Snakes have the ability to awaken us from our daily routine and rouse our interest about nature. Snakes are particularly good at eliciting a response.

Living with snakes will be a challenge for many of us. Taking safe, precautionary measures to make our homes safe for children and pets will reduce unwanted encounters. Educating ourselves and our children will reduce dangerous confrontations. It will also reduce the negative stereotypes that promote their extermination. These foreboding animals have the ability to allure us. They elicit a sense of mystery about the natural world that surrounds us. We all need awakening. Without the more ominous creatures, I'm afraid we will slumber in our sanitized lives.