Overkill and Underkill
part II

by Dr. Chris Ryan 

After reading the article I submitted a few days ago, it seemed strange to me that a physician would submit an article of this sort and give no opinions about what happens when something dies (or doesn’t). This follow-up shot will be my best attempt to make some of my medical knowledge--and not a little speculation--digestable. I welcome comments and questions, and I hope that I don’t appear to be talking down to anyone. Here goes.

Why Do Animals Die?

Seems like the best place to start is at the beginning. Why does an animal die? The answer about God deciding it’s time is perfectly acceptable to me, but I can’t claim to be able to help anyone understand more about that angle. Simply speaking, something dies when its computer (brain) goes down for good. Circulation (blood flow) supports the computer, which is why we generally use the pulse, or lack of one, to determine life and death. Generally, one can survive only a few minutes without circulation to the brain. Nearly anyone can feel a pulse, and while I’ve talked to people who claim to be able to feel brain waves, I can neither confirm nor deny this claim. The best indicator of death is the persistent lack of pulse--but it isn’t foolproof.

Not too many hunters check for the death of their prey by feeling for a pulse, I’d be willing to bet. Could get dicey with a big carnivore, or even a little antlered critter. This being the case, we rely on much less certain indicators, such as "it ain’t movin’" to determine the success of our kill. That brings me to the next question, and that is the difference between stopping and killing.

The Taylor Knock-Out Theory

John Taylor’s book African Rifles and Cartridges talked about the famous "Taylor K.O." method of determining effectiveness of a bullet against game. Of the K.O. values, he says:

They permit of an immediate comparison being made between any two rifles from
the point of view of the actual punch delivered by the bullet on heavy massive-
boned animals which are almost invariably shot at close quarters, and enable a
sportsman to see at a glance whether or not any particular rifle is likely to prove
a safe weapon for the job. In the case of soft-skinned non-dangerous game, such
as is generally shot at medium and long ranges, theoretical mathematical energy
may possibly prove a more reliable guide, provided a suitable weight of bullet is
chosen for the weight of animal against which it is to be used.

Further on in the same chapter, Taylor described more about the utility of the K.O. values, comparing the .416 Rigby to the .470 Nitro. He stated that the .416 would probably not knock an elephant unconscious if a frontal head shot missed the brain, while a .470 would. In the next chapter Taylor further explained:

...suppose a hunter...has followed two or three good tuskers into a dense, matted
tangle of brush. He can only see bits of one of the elephant, but can hear all three
of them. No vital spot is showing into which he can slip a bullet....if our hunter
has a .577 or .600 along with him, he can take it over now and, because of the
tremendous blow it delivers, can slam a heavy bullet from it into the tusker’s head
with the certainty that it will stun him for an adequate length of time to enable
him to tear his way thru the tangle of brush intervening and still be in plenty of
time to give the elephant another shot to finish him before he has recovered
consciousness. (emphasis added)

My reading of Taylor’s book suggests that, while the K.O. scale can generalize somewhat to killing power overall, the most important use he made of the scale was in a very specialized type of hunting, that of head-shooting elephant.

Now, before some of you start waxing apoplectic, let me reassure you that I’m not going to make much of that last point, and besides, I really like the K.O. scale What’s of interest to me here is the difference between killing power and stopping power. What happened to Taylor’s elephants that were knocked out was that they suffered what we call in humans a "concussion". In crude terms, the energy delivered to the brain, either directly or indirectly, short circuits the portion of the brain responsible for keeping the lights on, the reticular activating system. Sooner or later, the lights come back on, and the elephant wakes up and clears out, often minus its tail.

A similar thing can happen in the case of a spine shot: nothing about the spinal cord itself is so crucial to either man or beast that damage to this organ should result in instant death. On the other hand, when an animal goes out right away with such a hit, the reason could be found in the shock-absorbing cerebral spinal fluid (CSF) bathing the spinal cord and brain. An impact to this fluid system could certainly result in the same concussion to the brain, transmitted indirectly through the CSF.

What Is Happening?

In the mean time, in answer to the questions I can already hear some of you asking, while the animal is lights out (unconscious), other things could be happening, and usually are. One of the most important of these, from the standpoint of survival, is loss of blood from the blood vessels into the surrounding tissues. This could result in:

1) bleeding into the chest cavity, making use of the lungs mechanically impossible:
no oxygen to the lungs = no oxygen in the blood = no oxygen to the brain = dead;

2) loss of a critical volume of blood in any part of the body, producing shut down of the
pump system: lose enough blood (in humans, about 60%), and there’s no way to keep
the pump going: no blood to the brain = dead.

Other usual suspects on the list of "cause of death" include:

3) sufficient damage to the pump (heart) itself, which roughly equals 2), since the heart
is the biggest blood vessel;

4) critical nerve damage in the neck, which could paralyze the diaphragm and make
breathing impossible: no oxygen to the lungs = etc.; and, the most controversial,

5) "shock", which in humans is the malfunction or overriding of that part of the nervous
system responsible for keeping blood pressure high enough to assure adequate
circulation to the brain and other vital organs.

I can’t give you an authoritative opinion about how much, or even whether, shock actually occurs in animals. But do I feel that I’m on solid ground saying that, with a few exceptions, it happens much less frequently in animals than in humans. (Birds may be different.) I suspect that if African game really is tougher to kill than North American game, the shock factor may be the key to understanding why. If the severity of competition in an environment is high, then the level of alertness must be higher, in order to keep from either starving or being eaten. This alertness is maintained through high levels of adrenaline-like chemicals circulating and secreted in the body of such an animal. The same chemicals maintain blood pressure (roughly). An animal with a lot of these chemicals is less likely to suffer a sudden drop in blood pressure, but also will have a higher heart rate, in general. Its blood pressure is less likely to drop suddenly, but when shot, it may bleed out faster, as the heart is going faster. More about this below.

Velocity

Finally, and probably most controversially, I think that the effect of velocity on killing power may be due to effects on bleeding. I made reference in the first part of this to a comment sometimes attributed to Elmer Kieth: "ya could eat the bullet hole". This has to do with the amount of collateral tissue damage, whether from high pressure/velocity creating what’s referred to as the "temporary wound channel", or the bullet striking something (usually bone) that shatters and the fragments become secondary projectiles. All other things being equal, slower bullets cause less collateral damage than faster ones, of course.

Bleeding is caused by damage to blood vessels, traumatic or otherwise. Bleeding stops, if it stops, due to constriction of blood vessels and blood clotting. Constriction of undamaged vessels around the area of trauma is regulated by those same adrenaline-like chemicals. Blood clotting is stimulated by chemicals dumped into the blood when the vessels are damaged. In health, these chemicals reside in the walls of the blood vessels, ready to go to work if the walls tear. Sort of paradoxically, the more of the vessel substance that is damaged, the more of these chemicals are made available to start the clotting process. I think this accounts for why that little ram shot with the 130 grain bullets from the 270 Weatherby needed so many shots. The projectiles blew up several non-life sustaining parts of the little critter’s body, and maybe he clotted faster than he bled out, up to a point.

On the other hand, in the case of a large caliber bullet traveling at low to medium velocity, the effect is the opposite. A large hole is the result, but with less collateral damage. This means, in theory, a big hole in the vessels (all the way through), with the least non-penetrating damage to surrounding vessels. Therefore, biggest hole with relatively few clotting chemicals dumped into the would.

Disclaimer

Now a disclaimer: I realize I’m standing on mighty shaky ground on this point. The medical facts are there, but there may be something about the other circumstances that turn this part of the death and dying explanation into caca. I welcome comments and will quietly suffer curses, for a while anyway.

Going back to the first part of this kill story, the pig I shot was hit in a non-vital area, above the internal organs in the chest cavity. Pigs are just weird, that’s my excuse--this time. He may have bled out, eventually. The second shot, through the thoracic spine, resulted in spinal and brain shock, and both the big primary and profuse secondary projectiles went through the heart and lungs. The shock rendered him unconscious, and he bled out before he could come to.

Milt’s ram was heart-shot with a 150 grain 30-30 bullet from a TC at about 100 yards. He dropped dead on the spot; an act of God, as far as I can tell. Other than shock, there is nothing in my explanation of death that can explain that kill. Many heart-shot animals are described as jumping or hunching up and often running full speed before dropping dead. That makes sense. I didn’t ask Milt if he was using recycled Uranium or curare (a muscle paralyzing agent used by South American Indians on blowgun darts, and adapted by Western medicine men for use in surgery).

The shredded ram I don’t want to talk about.

That’s my explanation of how animals die. I don’t see myself as anything more than well-educated, curious, and fanatically interested in guns and hunting. I know of at least half a dozen readers of this site who are much more than capable of helping me extract my head out of the other end of my anatomy, if they see that as the problem. And by the way, if you’ve made it this far, you either have exceptional stamina, terminal boredom, or both. Let’s hear from you.

Write Dr. Chris