How come deer run for their lives when they hear a branch crack but will gladly wait in the middle of the road for a +100kph hunk of metal

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How come deer run for their lives when they hear a branch crack but will gladly wait in the middle of the road for a +100kph hunk of metal

In: Biology

The sound of an automobile is not in their shared evolution in the primeval forests. The sound of a snapping twig is. There are also likely other aspects to a snapped twig that are super/sub-sonic. Then there is the issue with headlights at night which can spook deer and paralyze them with fear

Broken branches are noises they understand to be bad. Road noise is background noise in most cases and so when they hear a louder version of it, they do not know what it means.

Similarly, a huge moving object with no visible legs is not immediately a threat since the predators they deal with a smaller than they are: they have no understanding of “big = bad” so do not have an immediate flight impulse.

Something else is that if it is headlight also blind them which causing a freeze response. Their eyes are much more sensitive to light then ours so it can take a minute to regain sight after being exposed to bright lights and so are unsure of what direction to move.

I’m seeing all this sh*t about the evolutionary triggers of forest sounds and honestly it sounds so contrived and divorced from reality. These deer have grown up around car sounds, more than likely, for generations. The deer have developed a somewhat sophisticated method of dealing with cars in their lives; often seen grazing on the side of the road with cars passing them by.

Consider for a moment that in the dark of night, while half your herd has crossed the street already, the car comes around the corner with it’s high beams on, going 20 miles over the speed limit, and blinds you. Unsure which direction to flee to, you are paralyzed by fear, knowing full well the speed and power that is lumbering towards you.

You do not know which way it will turn to avoid you, or come after you, or if it will turn at all.

What do you do?

Deer are programmed to run from noises in the woods in case it’s a predator like a bear, wolf, coyote, etc., but a vehicle is unknown to them so they don’t run from them some of the time or they will try and run across a road when vehicle is coming and end up being hit.

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