NORTHERN CALIFORNIA – This is the time of the year when rattlesnakes in the Berryessa Snow Mountain National Monument region are very active.
So, if you’re walking or hiking in the region keep an ear and an eye out for them.
There are several different species of rattlesnakes in California but the most common one in our region is the Northern Pacific Rattlesnake (Crotalus oreganus oreganus).
Rattlesnakes are a kind of venomous pit viper. The two small pits on the face detect thermal radiation and act something like a pinhole camera, working in conjunction with the snake’s eyes to provide it with a kind of “thermal map” of its surroundings.
Although snakes can see easily in daylight, their pits also help them to see in darkness, detecting temperature variations of 32 degrees Fahrenheit or less and allowing them to see the heat signature of any nearby prey.
Rattlesnakes also have an excellent sense of smell. Their noses and their Jacobsen organs (located in the roof of the mouth and accessed when the snake flicks its tongue) work together to detect and identify scents.
Hearing is another issue, though. As they don’t have any external “ears,” rattlesnakes are effectively deaf and depend on vibrations in the ground to let them know if there is anything – like a human – coming at them that they cannot yet see or smell.
When alerted to intruders, the rattlesnakes will often shake their rattles as a warning that they are nearby.
The rattles are made up of a series of interlocking, hollow “buttons” at the end of the tail. Special muscles in the tail can shake the rattle up to 50 time per second.
And by the way, no, you can’t tell the snake’s age by the number of buttons on the rattle. New segments are added to the rattle each time the snake sheds its skin (which can be several times a year if it’s able to eat a lot). Other segments can be lost or damaged as the rattlesnake ages, travels over rough terrain or encounters other animal combatants.
Rattlesnakes won’t always shake their rattles either, so don’t be fooled into thinking there aren’t any around you simply because you can’t hear them.
Be vigilant when on the trail. Don’t step or put your hands into areas where you cannot see (such as long grass, rock tumbles, or dense thickets), and step up on top of logs and rocks and pause for a moment to look over them before you step over them… there might be a rattlesnake tucked in on the other side that you’ll miss if you’re not careful.
Check around stumps and logs before sitting down to rest and never grab at what looks like a “stick” in the water. Rattlesnakes are excellent swimmers, and you don’t want that “stick” to bite you.
All rattlesnakes are born with fully functioning fangs, and in fact they have three pairs of back-up fangs in their heads at any one time.
The old fangs are shed and replaced about every six weeks. When the rattlesnake bites, special muscles on the sides of its venom glands squeeze the venom out into the fangs.
Some people believe that younger snakes are unable to control their venom, and are therefore more dangerous than adults, but that’s not the case.
All rattlers, regardless of age, can regulate their venom discharge, and adults have larger venom glands than juveniles, so papa can pump out a lot more venom than junior can.
The venom is a cocktail of enzymes, lipids, amino acids and other compounds, and is designed to bring their prey down, immobilize it, and start digesting it before it ever gets to the snake’s stomach.
One tiny fun fact about the venom: adult California ground squirrels have a natural immunity to it, and scientists have recently discovered that the snake’s venom is evolving to try to overcome that immunity.
As you go hiking and walking through the region just keep in mind that these guys are out there. And remember, too, that rattlesnakes very seldom bite unless they are provoked, so if you see or hear one, just give it a wide berth – 5 to 6 feet is a good distance – so it has somewhere to retreat to and it will mostly likely leave you alone.
And if you come across a recently deceased rattlesnake remember that the “bite reflex” may still be operational, so don’t pick up or handle dead rattlers.
Tuleyome is a501(c)(3) nonprofit conservation organization based in Woodland, CA. For more information, visit www.tuleyome.org . Mary K. Hanson is a Certified California Naturalist and author of the “Cool Stuff Along the American River” series of nature guides available at www.lulu.com .