We get used to almost everything. To the commute to work, which we eventually make without even thinking about it. To the clipless pedal, from which our foot eventually pops out as if by itself. Most of the time, that’s a good thing—it saves energy and keeps our minds free. Until the moment when exactly what we’ve tuned out would have been important. In the forest, this happens to a deer. On the trail, to the mountain biker.

The animal stops out of caution

Flight can save a life or cost one. Every leap into the thicket burns energy that determines life or death in winter. A deer that runs away from every mountain biker will starve to death faster than its flight would save its life. So it gets used to the person on the trail, who passes by—sometimes fast, sometimes slow—and never does anything. Provided, of course, that it isn’t just by chance a hunter on an e-bike, rifle on his back. And the deer? It sees no difference.

Yet wildlife distinguishes very clearly. Red deer in the Kellerwald-Edersee National Park in the heart of Germany remained calm when a hiker passed by on the trail but fled every time someone trudged across the terrain off-trail. What frightens them is not primarily humans, but the deviation from the norm. Anyone who moves in a predictable way—whether on foot or on a mountain bike—becomes part of the natural landscape. Anyone who strays from the trail becomes a threat.

That doesn’t mean that riding off-trail causes less harm to wildlife. On the contrary, it’s the most disruptive. The animal is startled, jumps up, and flees. In the case of the roe deer beside the trail, the damage manifests differently: not immediately, but only months later. The animal learns the rule “humans on the trail do no harm” so thoroughly that it continues to follow it even when it is deadly. This has been studied most closely in chamois: A study from the French Alps tracked 89 animals with GPS throughout the hiking season and the subsequent hunting season. The animals that had become most accustomed to humans during the summer remained the calmest in the fall as well, when hunters replaced the hikers. The hunting blind is set up, hidden among the trees—same location, same time, same calm movements as the mountain bikers and hikers before them. With roe deer, nothing else is to be expected. It doesn’t die because it’s stupid—on the contrary. It dies because it has learned well.

The Expert Trap: When Experience Becomes a Risk

You don’t have to be a roe deer to die this way. In avalanche research, this is referred to as the “expert trap”: About half of the avalanche victims in recent years were experienced and well-trained. They didn’t come to harm because the knowledge they’d acquired was of little use, but because it can also convey a false sense of security. Thus, the very experience that’s supposed to protect us actually blinds us. It’s always gone well so far. 

We base our confidence on everything that turned out well in the past. The jump we’ve always landed, the roots on our home trail that we know by heart. Every successful repetition makes us more confident and a little bit more blind. Until there’s a rock behind the root that wasn’t there before. For the deer, it’s not a rock, but the hunter in the tree stand. Most of the time, neither of them shows up. Until that one time. And that one time comes without warning, because everything looks exactly the same as usual. For the deer, the danger comes from the outside; for us, from within. Our hunter is our own confidence.

Caution can’t be forced

So should we just be more careful? If only it were that simple. Caution can’t be commanded. No one rides their home trail with the same tension as the first time, just because they resolve to do so. The loose grip, the high speed, the playful riding style: this sense of ease has been hard-earned over countless rides and isn’t something you voluntarily give up. The deer is in the same predicament. It, too, doesn’t shed its carefree nature on its own. For wildlife, as for us, it first takes a jolt—one that no one really wants.

What brings caution back is a moment of fright: The deer that survives a gunshot may become shy again afterward. The rider who falls once and gets back up rides more carefully afterward. Ironically, it’s the fall itself that restores what would have prevented the fall in the first place. You escape the trap, but only after you’ve been in it.

There’s a second way out. The capercaillie in the Black Forest doesn’t get used to people. It manages. It avoids the trails so thoroughly that, depending on the season, it loses up to 40 percent of its habitat. Those who refuse to adapt must disappear. So safety comes at a price. And who would willingly give up their home trail?

No one likes to give things up. So we carry on, trusting that everything will turn out all right. While the hunter lies in wait for the deer from his raised hide, ours lies within us. It’s the reassuring feeling that everything has gone well so far. And like the deer, we can’t simply switch off that feeling when it really matters. That’s what the forest shows us: It’s not just recklessness that’s dangerous, but experience as well. The greatest danger lurks not where we’re afraid, but where we’re no longer afraid.

One question remains: If even what’s wise, what’s practiced, and what’s been proven a thousand times over becomes a trap, what can we still rely on? Perhaps the most honest answer is the most uncomfortable one: nothing at all.