Lots of nifty details in this entry at Wikipedia.org, the online encyclopedia. Hiking’s the main thing I do outdoors — keeps the gear/complication costs down (what’s with bikes and all those sprockets, chain links and tires that go flat, anyway?) — so I figure I’ve got a pretty good lock on the basics. And anything I need to know I can figure out by asking Sgt. Rock (wanna know what to take on the Appalachian Trail? He’s all over it. .) Still, the Wikipedia entry has some linkworthy entries.

Dehydration can rapidly incapacitate a hiker, especially in warm weather. In conditions of low humidity, sweat evaporates so quickly that a hiker may not notice the water loss.

Everybody learns this the hard way. One thing I’ve noticed: if you’ve been sweating so hard that your upper lip tastes salty, you’re going to run out of water. Your first priority is not to get back to the car, but to get more water.

If deprived of food for several days, hikers may become malnourished. A human can survive for weeks without food, but malnutrition causes impaired judgment. Low blood sugar may have a similar effect. Carrying extra food will minimize risk to the hiker.

A corollary to this is: don’t be such a fitness freak that you’ve got no body fat to spare — you’ll need it for that time you fall down a ravine and have to wait a week to be rescued.

Hikers often seek beautiful environments in which to hike. Ironically, these environments are often fragile: hikers may accidentally destroy the environment that they enjoy.

The thing is, if you truly love nature the best thing you can do is stay the hell out of it. But by that logic if you truly loved animals you’d never keep pets. Don’t treat nature like you’d treat your own home: you might be a total slob. Treat it like you’d treat your grandmother’s home.

When two groups of hikers meet on a steep trail, there may be contention for use of the trail. To avoid conflict, a custom has developed: the group moving uphill has the right of way.

I always forget this rule, which seems counterintuitive anyway. People going uphill need a rest and people going downhill have gravity on their side; seems like it’d make more sense to stand aside for the downhillers. Main thing is, be courteous and don’t piss people off: they may be the ones who come to fetch you out of that ravine.

Hikers often enjoy the silence and solitude of their surroundings. This enjoyment can be disrupted by loud sounds, such as shouting or loud conversation.

Getting noisy on the trail is less of a big deal than getting noisy at a campsite when there’s people camped — and trying to sleep — nearby.