All three of these creatures deserve your respect, and you should understand a little bit about them.

RATTLESNAKES:

California has six poisonous snake species, and all are types of rattlesnakes: speckled, sidewinder, red diamond, Mojave, western, and western diamondback. These members of the pit viper family have wide triangular heads, narrow necks, and rattles on their tails. Rattlesnakes generally live in lower-elevation areas and are rarely seen above 6,500 feet. The standard advice is to give them lots of room. If you're hiking on a warm day when they might be out and about (they particularly favor temperatures in the 70- to 90-degree range), keep your eyes open so you don't step on one. Rattlesnakes often blend in very well with the brown and tan colors of an earthen trail. Also, watch where you put your hands, especially if you are scrambling over rocks.

Be particularly wary of rattlesnakes in the spring months; most bites occur then, when the snakes come out of their winter hibernation and are particularly active.

Most snakes will slither off at the sound of your footsteps; if you encounter one, freeze or move back slowly so that it can get away. They will almost always shake their tails and produce a rattling or buzzing noise to warn you off. The sound is unmistakable, even if you've never heard it before.

Although rattlesnake bites sting and are quite frightening, they are only rarely fatal. Rattlesnakes will sometimes strike without biting, and even when they do bite, their bites do not always release venom. If you should get bitten by a rattlesnake, snake bite kits (or venom extractors) are basically useless. Instead, your car key is your best first aid. Don't panic or run. Walk slowly back to your car, then drive yourself to the nearest hospital. Avoid running or unnecessary movement, because this helps circulate the venom through your system. The bitten area will probably start to swell, so remove any jewelry or constricting clothing from the area. Do not apply ice to the wound, and keep the bite area below the level of your heart. This is usually easy, since most bites are on ankles or hands. Most importantly, stay calm and move slowly.

MOUNTAIN LIONS:

The mountain lion (also called cougar or puma) lives in almost every region of California, but is rarely seen. When the magnificent cats do show themselves, they receive a lot of media attention. The few mountain lion attacks on California hikers have been widely publicized. Still, the vast majority of hikers never see a mountain lion, and those that do usually report that the cat vanished into the brush at the first sign of nearby humans.

If you're hiking in an area where mountain lions or their tracks have been spotted, remember to keep your children close to you on the trail and your dog leashed. If you see a mountain lion and it doesn't run away immediately, make yourself appear as large as possible (raise your arms, open your jacket, wave a big stick) and speak loudly and firmly or shout. If you have children with you, pick them up off the ground, but try to do it without crouching down or leaning over. (Crouching makes you appear smaller and less aggressive, more like prey.) Don't turn your back on the cat or run from it, but rather back away slowly and deliberately, always retaining your aggressive pose and continuing to speak loudly. Mountain lions are far more likely to attack a fleeing mammal than one that stands its ground. Even after attacking, they have been successfully fought off by adult hikers and even children who used rocks and sticks to defend themselves.

BEARS:

The only bears found in California are black bears (even though they are usually brown in color). A century ago our state bear, the grizzly, roamed here as well, but the last one was shot and killed in the 1850s. Black bears almost never harm human beings, although you should never approach or feed a bear, or get between a bear and its cubs or its food. Black bears weigh as much as 350 pounds, can run up to 30 miles per hour, and are powerful swimmers and climbers. If provoked, a bear could cause serious injury.

There's only one important fact to remember about bears: They love snacks. The average black bear has to eat as much as 30,000 calories a day, and since their natural diet is made up of berries, fruits, plants, fish, insects, and the like, the high-calorie food of human beings is very appealing to them. Unfortunately, too many California campers have trained our state's bears to crave the taste of corn chips, hot dogs, and soda pop.

Any time you see a bear, it's almost a given that he's looking for food, preferably something sweet. So keep your food packed away in bear-proof containers when you're camping, and get an update from the rangers in your park about suitable bear precautions. Bears are sometimes encountered on trails, although not as frequently as in campgrounds. If you're hiking, bears will most likely hear you coming and avoid you. If one approaches you, either on the trail or in camp, yell loudly, throw small rocks or pine cones, and try to frighten the bear away. A bear that is afraid of humans is a bear that will stay wild and stay alive.

Backpackers should always use plastic bear canisters to store their food for overnight trips. Hanging food from a tree is largely ineffective and now illegal in many places, including Yosemite and Sequoia and Kings Canyon National Parks. You can rent or buy a bear canister from most outdoor stores, or from many ranger stations in national parks and national forests.