We're nearing the end of a nice hike in Red Rocks Park and we've paused on a rock outcropping to drink some water and admire the expansive view of the Denver Metro area and the endless prairie beyond. A small knot of people has gathered lower on the trail. A pair of mountain bikers nearby say that someone in that group had been bitten by a rattlesnake.

Indeed, as we descend the trail, we see that one man in the group is sitting on a rock, his left leg extended in front of him with blood oozing from twin puncture wounds on his shin. There's an enormous cell tower atop nearby Mount Morrison, so we're not exactly miles and miles from civilization, and the bite victim is talking on a cell phone to, presumably, a 911 dispatcher or a doctor or something, calmly asking if he should make an incision in the wound. We say, "Good luck" as we pass, and inwardly I am simply astounded at how cool and collected the guy is. I'm of a like mind with the good Dr. Indiana Jones when it comes to snakes, and I can only imagine how I would react to a rattlesnake bite. Still, he's doing the right thing, according to the experts: sitting still, keeping the bite low and not totally freaking out.

As we continue hiking, we hear sirens approaching on the nearby road. We pass first one park ranger heading the opposite direction, then another and finally when we're nearly back to the trailhead, the West Metro Emergency Services crew, trundling a thing that looks like a combination stretcher/wheelbarrow, and moreover like a very unpleasant but necessary ride for the bite victim back down the bumpy, rocky trail.

Later on, back at home, we're eating dinner and watching the "Fresh Water" episode of "Planet Earth." In the "behind the scenes" bit that follows the episode on the disc, we see the film crew's attempts to capture footage of a piranha feeding frenzy. During this, they speak with several locals who show off their (really wicked-looking) scars from piranha bites.

Both the day's events and what's on television serve as a reminder of a simple truth. It's a bit of a cliché, but true nevertheless. Human beings are undoubtedly the dominant species on the planet - but we're as often as not visitors in habitats to which we are unsuited, and will frequently come off worse in encounters with the natives. We are spectacularly adaptable, able to survive and thrive in nearly any environment. But the fact remains that the western rattlesnake has been living in the Rocky Mountain region since there have been Rocky Mountains, and the piranha in the Pantanal since there has been an Amazon River. This is their home turf and they will defend it, aggressively if necessary.

That said, the "Planet Earth" photographer was in the water only a few feet away from the piranha feeding frenzy and came away without a scratch. Rattlesnakes tend to be shy and avoid humans when possible; in all the years I've been hiking and camping in Colorado and Wyoming, I've never actually seen one. Writers, filmmakers and most especially bored journalists like to play on the primal human fear of such things, but the number of people who go hiking in snake habitat areas and don't get bitten is orders of magnitude greater than the number who do. Jaws is scary and stories of shark attacks sell papers, but in comparison with the number of people who actually go swimming and diving in the world's oceans, shark attacks are vanishingly rare. "Killer" bees rarely kill and, the occasional lunatic like Timothy Treadwell notwithstanding, grizzly bears almost never actually attack people.

As we headed back down the trail, we speculated as to just how someone could be bitten on such a heavily human-populated trail. Our surmise was that the victim had stepped off the trail to cede right-of-way to someone else, and happened to step in exactly the wrong spot. Therein lies the rub - though "nature" is safer than a sensationalist media suggests, the danger is still there. Caution and respect are the key. "Grizzly bears almost never attack people" ≠ "Hey, wanna ride a grizzly bear?" and "Rattlesnakes tend to be shy and avoid humans" ≠ "Putting your foot down off-trail without looking where you're stepping is a good idea!"