Ticks are small parasitic arachnids that make a living by hematophagy, a fancy word for blood-sucking. About the size of a grain of rice, these dark colored pests feed on the blood of mammals, birds and sometimes reptiles and amphibians. They are widely distributed throughout the world, though most common in areas with warm, humid climates since ticks require some air moisture to undergo metamorphosis and cold temperatures inhibit egg development. They can be a bane to hikers, pets, livestock, as well as wild animals. Ticks are most common in environments with many large mammals that help to feed and distribute the pests. In addition to the nastiness of having a parasite burrow into the skin, they can be carriers of a number of diseases including Lyme disease and Rocky Mountain Spotted Fever.
Despite the repugnant features and habits of ticks, there are measures you can take to minimize their impact when you are hiking in areas known to harbor them. Of course the easiest way to avoid them is to stay out of their habitats, but this leaves many beautiful and interesting places off-limits. Knowing their habits and behavior can help you defend against them and allow you to enjoy an outing without undue anxiety and apprehension.
For the hiker, the most significant threat from ticks is in their adult female form, though ticks in the nymphal stage can also pose a hazard. Male ticks rarely feed and will latch onto mammals primarily in search of females. The most common types of ticks found are the hard shelled ticks from the Ixodidae family. They seat themselves at the tip of tall grasses and other plants, waiting for animals to brush by at which time they jump to their host. They then crawl in an upward direction, looking for soft underbellies and other tissue which are most easy for them to burrow into. It generally takes about an hour for a tick to burrow into its host once it has found a suitable location. A tick will feed for 3-7 days before becoming engorged, drop off the host, and lay eggs to begin the life cycle again.
Ticks are most active in spring and summer, between March and October, but can be found in any month or season. From personal experience, ticks appear to be far less active at night than during the day. Ticks can be found from sea level to over 8,000ft. Though they dislike cold temperatures, wild sheep and goats can carry them to high altitudes where they can still be a nuisance (the Ruby Mtns in Nevada are one example). In drier climes they are more often found closer to streams and water sources, but can also be encountered in dry chaparral country.
Like most outdoor enthusiasts, at one time I was very apprehensive about tick encounters. I've since been in places where I've had hundreds of the critters assault me in the course of a few hours, and have had thousands of tick encounters over the course of the years, but with good defenses, only a few have found their mark. Now I don't worry much about them at all, but am cautious in their territory and diligent in watching for them.
There are a number of things one can do to help defend against ticks. First and foremost is your clothing. Note that tick movement is inherently upwards. They climb up to the end of a stalk, then climb up the host to find soft tissue. Ticks are most often first located on your lower legs or pants, crawling up from there. They will stop if they reach the underside of a pocket flap or the seam of zip-off pants. This may seem like devilishly clever behavior, hiding from the unsuspecting hiker, but it is really just the result of their upward-seeking mobility. It should be clear by now that wearing shorts is just asking for trouble - there are plenty of soft places on the human leg that a tick can burrow into. If you expect ticks, always wear long pants. Tuck your shirt into your pants. That way, a tick crawling up your pants will crawl onto the outside of your shirt when it reaches your waist rather than the inside. Tucking your pants into your socks will similarly help, but not to the same degree - most ticks latch onto you above the bottom of your pants.
Ok fine, but once they crawl up my shirt they're eventually going to reach my head and burrow into my scalp, right? Yes, they will - if you let them. So the second most important step to take is to spot them and remove them. Because they are primarily dark colored, wearing light colored clothing will make them far easier to see. If you spot a tick, brush it off. trying to crush it to death between your fingers is almost impossible with hard ticks. If you catch the tick by surprise they are easy to flick off your clothing. Often they will dig in with their legs if you fail on the first pass, making them harder to remove. Keep flicking and they will eventually come off. Once you've found the first one, you should do regular tick checks to find and brush off additional pests. You can easily overdo the number of tick checks needed if you are overly zealous in looking for them. Ticks don't move all that fast, so you don't have to spot them the moment they first land on you. Plus, if you are hiking in brushy terrain, most ticks will be knocked off you without your even knowing it. Don't get overly paranoid. Even in heavily infested areas, I don't usually check more than about once every 15 minutes. Flicking ticks off while on the move is a more advanced technique - suitable for the experienced hiker used to dealing with these pesky critters.
Sometimes you have to crawl through brush or walk through stuff well over head level. In these cases, ticks may end up on any part of your clothing. A hat can help protect your scalp and if the hat has a sun-protection flap that drapes your neck, even better. Once you are done crawling or out of the hazard zone, a more thorough check is warranted. If you have to do this for long periods of time and you know the area is tick-infested, you are simply asking for trouble. Make sure it's worth it.
Once the hike is over, or perhaps when you are out of tick territory, you should do a more thorough search for the creatures if they were particularly numerous. Some may have slipped through your defenses, others may have lodged in your pack. Remove your pack and have someone check your backside (not a bad idea to do this periodically during the hike). Strip naked to be sure. You don't have to do this in the presence of others - if you're taking a shower it's the perfect time to do a thorough check. Run your hands over your body looking for small lumps. Check your private parts and your scalp. Usually an embedded tick will cause a mild pain at the location, so check anyplace that feels like a mild burn. Getting ticks out of your pack may take more work than your clothing or body. Empty it out and do a thorough check, or if you're lazy at least set it aside, away from your sleeping area or other clothing. Ticks can easily survive wash and dry cycles, so laundering isn't an effective disinfectant for clothing - do a visual check when you remove them.
Another effective deterrent is the use of an aerosol clothing spray containing Permethrin, a neurotoxin. It remains effective even after 4-5 washings, and does an excellent job of keeping ticks off you. Be warned that Permethrin is dangerously toxic to cats and fish, so if you have these in your home it is not advised to use this method. DEET is excellent as a mosquito repellent, but is less effective for ticks. Because it is applied to the skin rather than clothing, DEET has a number of unpleasant downsides to it. Still, the DoD (US military) recommends using both Permetrhin for clothing and DEET for skin to prevent tick bites. Personally I stay away from DEET unless swarmed by mosquitoes.
Ticks are not usually a problem on feet, though they can become lodged in the crevices of shoes or embedded in socks. These should be checked if you have traveled through a tick zone.
A selfish method of defense is to have your hiking partner go first along the route. This seems to attract 75-90% of tick encounters. This knowledge can be used in a more altruistic manner if you have a member of your party that is particularly squeamish in regards to these pests - have him/her go last.
The best way to remove hard ticks is mechanically. Tweezers can be used to grasp the tick close to the skin and apply steady upward pressure without crushing or twisting the tick. If no tweezers are available, use your fingers. If the head becomes detached and stays in your skin, don't panic. Though common talk says you are screwed and will die of infection, this is hardly the case. When you get a chance, dig out the head with a sterile instrument - tweezers or the point of a knife. If available, apply an antiseptic to discourage infection. This will usually be the end of it. Watch for infection and see a doctor if one develops.
Other removal methods are generally less effective. These include smothering with creams, gels and toxic agents, applications of heat or cold, and other methods.
If you have been bitten long enough for the tick to get his head under your skin, keep an eye out for potential tick-borne illnesses. These are not illnesses that strike suddenly and kill you before you even get home, so don't panic. There are about 25,000 cases of Lyme disease reported each year in the US. Lyme disease has a classic circular red rash that appears around the bite area from 3-30 days after the bite. An infected person may also experience flu-like symptoms, such as headache, muscle soreness and fever, though without nasal congestion or runny nose. See a doctor if you suspect Lyme disease. A prompt course of antibiotics will generally cure you. Not all areas with ticks are prone to Lyme disease. Below is a map of the US with relative risks by area.
There are also approximately 800 cases of Rocky Mountain Spotted Fever reported each year in the US, but the distribution is much broader than the name suggests. Early symptoms include fever, nausea, vomiting, headache, muscle aches and loss of appetite. Later symptoms include rashes, abdominal and joint pains. Treatment is with antibiotics and usually curative.
There certainly is a good deal more that can be said about ticks. Yes, they can kill you, but so can lightning, mountain lions, bears and a thousand other things. Though the risk of serious illness is non-zero even in California, I didn't want to focus on tick-borne diseases so much that it looks like a million other fear-mongerings that seem pervasive in public education these days. I'd hate to contribute to someone being afraid to venture out because of yet another thing to fear in the Wilderness. Mostly, ticks are a nuisance that can be dealt with in a straightforward and practical manner - they are not something to be feared. For those that would like more in-depth information, there is quite a bit available. Here's a start:
The California Department of Public Health