Tucson Weekly

Read Up on Reptiles

Warm weather has arrived, and so has the season of poisonous critters

Lee Allen Apr 27, 2006 4:00 AM
You know those times when you wake up in the middle of the night, unable to sleep, and decide to pick up a book and read until the Sandman returns? Tread Lightly is NOT the book to read at that hour--although it is a book that Tucsonans could benefit from by reading during daylight hours.

The subtitle of Tread Lightly reads Venomous and Poisonous Animals of the Southwest, and now that critter season has arrived, prompting the annual spate of rattlesnake mania, this is important stuff. "We want to take the fear out of living in or visiting in the wilderness of the Southwest," say authors Rich and Margie Wagner. "These animals are an integral part of the ecosystem, and encounters with venomous or poisonous animals should be enjoyed safely. An awareness of how an animal is likely to behave can take the fear out of an encounter, and knowing what--or what not--to do if you are stung or bitten can save your life."

Not only did the Wagners' write the book; they did their own photography and are eminently qualified to do both. Rich Wagner is an M.D., a board-certified emergency-medicine physician with a doctorate in pharmacology and a special interest in envenomization (injection of venom) and poisonous animals. Wife Margie is a registered nurse. He has been a professional wildlife photographer for more than two decades. She is an accomplished photographer who specializes in nature photography.

While the editorial content covers amphibians and arthropods as well as reptiles, reader interest will probably focus on the Serpentes, specifically the Viperidae family (vipers) that includes rattlesnakes. By far the most common venomous snakes in the Western United States, the front-fanged pit vipers are represented by about 15 species of rattlers. Although rattlesnakes are found across most of the United States, the greatest diversity of species and highest overall density are in the Southwest--ranging from desert lowland sand dunes to timberlines above the 7,000-foot level. They vary greatly in size and can range from a full-grown pigmy rattler of just less than 2 feet to the largest buzztail in the Southwest, the Western diamondback, with maximum lengths of up to 7 feet. Lifespan in the wild is subject to conjecture, but they've been known to live up to 20 years in captivity. Strike speeds measured at mid-strike can average 8 feet per second.

The ominous high-pitched buzzing of an agitated snake comes from a high-frequency vibration of 25-100 cycles per second produced by the snake's specialized tail muscles. And while the rattle may get the most attention, it's the head that is the "business end" of the snake, with fangs like hypodermic needles to deliver venom.

Three-fourths of all rattlesnake bites in the Southwest occur between April and September, when both snakes and people are active in the outdoors. "Most rattlesnake bites can be prevented," write the authors. "Based on the circumstances of the bite, there are two categories--'legitimate' bites where the recipient was not intentionally interacting with the snake, and 'illegitimate' strikes where the victim was intentionally interacting with, and often provoking, the snakes. Illegitimate bites are obviously preventable. If you don't want to get bitten, stay back, and don't mess with a rattler."

The Wagners have compiled statistics from a variety of sources which show that males (average age: 24) are bitten up to four times as often as females; three out of five victims were intentionally handling the snake; four out of five were bitten on the finger(s) or hand, and about a quarter of all bite victims appeared to be intoxicated. "The message is clear," write the authors, "if you don't intentionally interact with a rattlesnake, the odds of getting bitten are pretty low."

Aside from the mind-your-own-business philosophy, there are some other helpful hints given:

· Stay on trails whenever possible.

· Wear thick leather boots and shin guards when walking through tall grass.

· Avoid placing your hands or feet in places you cannot see.

· Baby rattlesnakes may not be able to rattle, but they can strike and inject venom.

· Do not handle dead snakes, as the bite reflex can last up to an hour even in the head of a decapitated snake, and envenomations are possible.

More than 1,000 people a year are bitten by rattlesnakes, with a handful of deaths resulting. By comparison, 15,000 people a year are stung by bees and wasps, and nearly 4.5 million folks get bitten by dogs. Although the overall risk of getting bitten by a rattler is very low, consequences can be severe, and that's why the knowledge available in this book is beneficial to desert dwellers.

Just don't read the book in the early morning hours when it's dark and scary.