I heard that loss of blood kills shot animals, a lot. But a few times, I heard that mechanical shock kills animals. For example in this video (starts to play at the right spot; relevant from 14:35 to 15:03).

That loss of blood kills an animal seems pretty obvious as the brain can't function without being supplied oxygen and it can't be supplied oxygen if there is no blood to carry the oxygen.

If the mechanical shock is applied to the head, it also seems somewhat reasonable. I guess it could be that the shock destroys vessels in the brain. But other than for a headshot: Is there a biological reason why an animal couldn't continue to live after experiencing mechanical shock due to being hit by a small projectile (being hit by a truck which is able to accelerate the entire animal doesn't count)?

  • $\begingroup$ @canadianer Yeah, moving. Of course, you can move a car slow enough so it's true. If you move a car slow enough, its kin. energy is equal to that of a flying fruit fly. Example: The mass of the bullet an AK 47 fires is 7.9 g = 0.0079 kg. Its muzzle velocity is 715 m/s. A car typically has a mass of at least 1000 kg, so let's take that. The kinetic energy of that bullet is equal to the kinetic energy of the car when the car moves at sqrt(0.0079 kg * (715 m/s)^2 / (1000 kg)) = 2 m/s. You don't die when hit by a car moving at 2 m/s. Alternatively, you could walk against a car with 2 m/s. $\endgroup$ – UTF-8 May 5 '17 at 22:54
  • $\begingroup$ Yeah I pressed the square root button instead of the square button in my rough calculation. I'd better just stick to biology… $\endgroup$ – canadianer May 6 '17 at 7:07

With a small projectile you will always get some sort of shearing forces: the tissues directly impacted will accelerate faster than adjacent tissues, and so on. This can cause tearing of many tissues, including blood vessels, but other tissues as well.

In the context of the brain, the effects of traumatic brain injury are a constant area of research, for example see here.

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  • $\begingroup$ But is that shock sufficient for killing a reasonably-sized (deer, wolf, human) or big (giraffe, elephant, hippo) animal? Is it what actually kills an animal when a hunter shot it? As stated in the question, the effects of hitting the heat aren't in particular interest for this. Typically, less fragile parts of an animal's body are hit. You probably could die if someone threw a rock at you hard enough and hit your head but you wouldn't die if that rock hit your stomach or thigh. $\endgroup$ – UTF-8 May 5 '17 at 22:58
  • $\begingroup$ Usually hunters are aiming for vulnerable organs like the heart. If a hunter hits a deer in the gut, it will probably die later from blood loss or much later from infection. If your side-view mirror clips a deer in the head as you drive by, you might cause enough concussive force to cause death even without vascular trauma, though both would be a factor. $\endgroup$ – Bryan Krause May 5 '17 at 23:09
  • $\begingroup$ But if the hunter doesn't hit a vital part (e.g. hits the deer's thigh), can the shock kill a deer or will it just really ruin its day and handicap it? $\endgroup$ – UTF-8 May 5 '17 at 23:25
  • $\begingroup$ I can't think of any reason, besides the possibility for blood loss, eventual infection, or a secondary cause due to impaired mobility, that a gunshot to a deer's thigh would kill it. $\endgroup$ – Bryan Krause May 5 '17 at 23:50

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