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Northern Pacific Rattlesnake

Crotalus oreganus oreganus

by Michael Marchiano

Northern Pacific Rattlesnake

Michael Marchiano

Ever since the story of Adam and Eve, western culture has had an aversion to snakes. The fact that a few species are venomous just adds more fear. In Northern California, there is only ONE venomous species of snake, the Northern Pacific Rattlesnakes (Crotalus oreganus oreganus). All other snakes in the Bay Area are harmless.

Our local rattlesnake is very distinctive from other local snakes because of the rattle attached to its tail and the diamond-shaped head that is far wider than its neck. Its coloration can vary, matching its environment. When young, its blotchy pattern is generally much more distinct, fading as the snake ages. Color can vary from drab olive green, to dusty brown, reddish brown, grey, or golden with the darker irregular blotching along the length.

When encountered, this snake is not aggressive and either freezes so as not to draw attention to itself or flees, trying to escape any confrontation. Like any wild animal, it will attempt to defend itself when molested or attacked. This is when people see it in its most often portrayed position of coiled, tail rattling its warning, and head held high to observe its attacker. Like all snakes, rattlesnakes do not attack people. The venom they possess is for the purpose of killing small prey animals and they do not want to waste it on a two- legged predator.

There are many, many myths and exaggerations concerning snakes in general, but there are even more concerning rattlesnakes. The Northern Pacific Rattlesnake rarely grows more than 36 inches in length - one over 48 inches is a real granddaddy, yet I commonly have people tell me stories of the 6- to 7-foot rattlesnakes they have encountered in the Bay Area (fear and imagination go together). The actual striking distance for a snake from a coiled position is approximately a third the distance of its body length, but let’s give the snake the benefit of half the distance, just to be safe. That means a three-foot snake can only strike out approximately 1-1.5 feet. You would have to be right in that snake's face to get him to strike. They do not strike without reason. Leave the snake alone and he will leave you alone.

In late summer to early fall, we enter the birthing season for snakes. Rattlesnakes are one of the few live-bearing snakes (opposed to egg-lying). Mother rattlesnakes can give birth to 7-15 young who actually stay with her for the first couple of weeks. The young are distinctly patterned replicas of the adult except they initially have a single button on their tail. They will not get a second rattle until they shed their skin for the first time, generally within a few weeks. Rattlesnakes get a new rattle every time they shed and may shed three to four times in the same year. Therefore, the number of rattles does not tell the age of the snake. Secondly, as the snakes age, rattles will commonly break off.

Young rattlesnakes possess venom when they are born - it is the same venom as the adults, just less of it. The bite of a small rattlesnake is NOT more venomous than an adult, but adult rattlesnakes have been known to give a dry bite (no venom), 30 to 40 percent of the time. The young snakes are still learning to control envenomation and therefore do inject venom with each bite. Nevertheless, any bite from a rattlesnake needs immediate medical attention. Although death from a bite is very rare (in the United States, 10-12 deaths from venomous snakebites occur annually per 10,000 bites), hospitalization with severe pain and suffering is the norm.

Rattlesnakes, along with all other snakes, fill an important ecological niche and should not be killed. They eat numerous rodents and in turn are attacked and eaten by larger predators, including hawks, eagles, owls, bobcats, and coyotes.

As a rule of thumb, do not try to touch, capture, pick up, or tease any wildlife. Even a cute little cottontail rabbit will bite and claw to defend itself if confronted.

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