Spring is the period of greatest activity as rattlesnakes emerge from winter hibernation. Their dens are usually in rocky outcroppings in the hills or in deep animal burrows. They are hungry and looking for mates, as this is also the breeding season. It is mistakenly believed that rattlers are active only during the heat of the day. Not only do they rest during the heat of the day, sheltered from the sun, they are adept hunters in the dark.
During periods of excessive heat during the day, many diurnal animals become crepuscular (active at dawn and dusk) or partially nocturnal. Thus rattlers are more nocturnal in summer than during the spring or fall, and adults are more nocturnal than juveniles. When out walking, hiking or camping, precautions should be taken from early morning to late evening, as temperature, season and humidity can all affect just when rattlers will be active.
Dogs encounter snakes during play or work in the snake's natural habitat. Most bites to dogs occur on the face or extremities. The rattlesnake bite is generally hemotoxic, which means that it exerts its toxin by disrupting the integrity of the blood vessels. The swelling is often dramatic with up to one-third of the total blood circulation being lost into the tissues in a matter of hours. The toxin further disrupts normal blood clotting mechanisms leading to uncontrolled bleeding. This kind of blood loss induces shock and finally death. Facial bites are often more lethal as the swelling may occlude the throat or impair ability to breathe.
Symptoms of an envenomated bite include: immediate pain, swelling and discoloration, weakness, difficulty breathing, nausea and vomiting, and hemorrhaging from the wound site.
To prevent bites, take precautions such as wearing protective pants and boots, and look carefully where you are walking. Keep your dog on a leash when hiking, and stay out of tall grass. Do not let your dog investigate piles of wood or rocks.
So back to our original question: What do you do now that you and your dog have encountered a rattlesnake? When you hear a rattle, freeze until you identify where the sound is coming from; you don't want to accidentally step on the snake when trying to flee. Once you have spotted it, give it time to move away. If it doesn't, move slowly straight away from it; don't walk to one side or the other as that could be perceived as threatening.
If you or your dog are bitten by a rattlesnake, stay calm and seek medical or veterinary attention immediately.
--Dr. Franklin Utchen, shown with his dog Tory, has been practicing veterinary medicine in the San Ramon Valley since 1989 and currently co-owns Bishop Ranch Veterinary Center & Urgent Care. For questions or comments e-mail firstname.lastname@example.org.
* Don't move planks, rocks or logs by hand - use a stick or crowbar until you can see under it.
* Don't reach into holes in the ground, rocks or trees, woodpiles, even abandoned buckets and tires.
* When walking, stay in cleared areas as much as possible, and keep a visual and auditory look out for rattlers.
* Take most care when the temperatures are moderate, not only when they are very hot.
* Step on a log, not over it, so you can first look down to make sure there is nothing concealed on the other side.
* Don't handle a dead or injured snake. Muscle contractions can still cause envenomated wounds.