Informative Deer Jumping String Video
Equipment
Very good video on speed of bow and deer dropping.
That was good. Ol' TBM noted on here one time about deer with their head down can drop faster than those with their head up. I never forgot that because it made sense to me. Was neat to see that was noted in this study as well.
This data doesn’t seem accurate to me. The speed of sound travels at 1100 fps., so it takes 0.1 second to reach the deer at 40 yards. The three arrow speeds tested would take 0.47, 0.43, and 0.39 seconds to reach the deer, respectively. So, the deer would have 0.04 seconds less time to react to each progressively faster arrow. The total amount of drop/duck should be roughly linear between those 3 speeds. Something like 9”, 7”, and 5” at 40. Not 10-10-5.
Matt
I watched this and I guess they tied the equipment together so that the balloon released when it was sensing the sound of the bow being shot. Being a traditional guy, I would like to see a quiet longbow like I shoot brought into the test. Arrows shot would be in the 170 fps range but the bows are so quiet that I wonder what the results would be. I've had 1 deer drop on me in the last 25 years and I think it was because he could catch some movement as I drew with his side vision. I just don't have deer move at the shot. I don't shoot over 20 yards anymore.
I also used to think a head down, feeding deer was a good time to shoot. I saw this some where else a while back and now shoot when the head is up. (doe hunting feeding deer is a hoot but challenging.
DIY Sportsman on YouTube has a video on string jumping that was published 2 days ago. He is a smart young man and has some good data.
I like to shoot when the deer's head is up, and it's looking AWAY from me.....or when the head is behind a tree!
I had a deer one time 15 yards away, broadside, with his head down. I was up in a tree a good 15'. I took the shot and he ducked SO far and fast that the arrow was about a FOOT above his back!!!
Very interesting. Ever since I started Bowhunting I’ve made a whisper quiet bow my number one priority when shopping. I think I’ve had 3 deer “duck” in all my years of hunting. Also another reason I LOVE a walking shot under 25 yards. Guaranteed no ducking. Rutted up bucks also duck way way less imo
I also wonder how much difference a loud, hissing broadhead and vane combo makes versus a more quiet combo. There are other variables as well, like the amount of wind noise. Calm windless days are the worst, obviously. Does with fawns are way more spooky, too.
The whole premise of this study is the deer *can* (but not always do) drop at the speed of gravity upon hearing the shot. Assuming that's true, the distance the deer drops at any shot distance is not too difficult to calculate....I think...
First you calculate how long the sound takes to reach the deer. Sound travels at roughly 1100 ft per second.
40 yards/1100 fps = 120 ft/1100 fps = 0.1 second
Add to that the reaction time of the deer, which is said to be around 0.05 seconds, so the deer starts to react 0.15 seconds after the shot.
Then calculate how long the arrow takes to reach the deer. We'll assume a constant speed for the entire length of the shot, although that's not perfectly accurate, it's close enough. We'll use the slowest arrow speed of 258 at 40 yards in this example.
40 yards/258 fps = 120 ft/258 fps = 0.47 seconds.
Now, subtract the sound travel and reaction time from the arrow travel time, and that's the total time the deer has to drop before the arrow gets to him.
0.47 - 0.15 = 0.32 seconds total time to drop.
The formula to determine how far a free falling object drops in a fixed amount of time is:
1/2 * speed of gravity * fall time * fall time = total fall distance.
1/2 * 32.17 * 0.32 * 0.32 = 1.6 feet
That's a lot different than the 10" that this study came up with. It's early, and I'm working on my first cup of coffee, so please check my math and correct any mistakes I made.
Matt
So funny folks are still studying this. Deer need to duck down bend their joints to run, jump, etc. either by instinct, sound, sight or just because they just want to.
Have seen them do it plenty of times with traditional and modern high speed equipment, AND a crossbow. That said I shot a buck who has his attention on a doe three (3) times before he ran. I really questioned myself on the first two shots, but the shots were all in the vitals complete pass throughs. Shooting fingers on a old Golden Eagle, 2 blade fixed head and over 70 lbs.
I don't care what the math says, they drop a lot faster than what anyone would dream. Ask the guys shooting Coues deer or southern whitetails consistently.
What blows me away, is how a pressured Whitetail can decipher the sound of an arrow leaving the string, from any other "alarming" noise, and react "uncharacteristically"?
Had a mature doe duck my shot back in October, slightly quartered away, head down, 40 yards (I think my arrow speed is probably in the 250ish range). That evening, I watched a feeding doe for over an hour. Every time she heard something she was concerned with, she would quickly pull her head up (not "lay down").
Having little experience with Whitetails, it gave me a new respect for them..
It's the sound of the bow not the arrow that causes the jump... I think it was the Wensels that made a video of this years ago and if I remember correctly, under about 18 yards their reflexes was not quick enough to avoid the shot...
They are not reacting differently because they know its an arrow. The "ducking" is simply the first part of their effort to run. They drop down to dig their feet in for traction.
This video solves the mystery. Deer do not react differently to lighted knocks.
Deer don't drop at the speed of gravity. The duck with the energy of a released coil spring and it's a lot faster.
That's why I like them at 12yards! ^^^
A deer would have to be gripping the ground and actively pull itself down to drop any faster than the speed of gravity.
The head and neck being in a down position acts as a lever to bring the body down faster than the rate of gravity. The deer isn't a static sack being dropped from a rope.
^^^Only if you shoot the with the head down. Shoot at them head up and they can only drop maximum at speed of gravity.
This falls into the category of "DUH, didn't everyone already know that?"
But if the head is up, the deer can drop no faster than the sack. Gravity is a law that can’t be broken.
I’ve watched a lot of our own video and deer that drop usually begin to do so when the (~275fps) arrow is just arriving. Every time we had problems with string jumpers (coc duckers) it was outside of 25 yards. 30 was the worst - close enough to alarm the deer but far enough that they had time to drop. From 20 and in, they can’t drop soon enough to make a difference. (Assuming >250 fps and HEAD UP).
I'd say a loud arrow is more of a factor than a loud bow.
It's not rattling_junkie, sounds travels around 1100 fps, no bow shoots that fast...
I agree 100% with rattling_junkie. I think they hear both, but the arrow is what is making them duck.
Why is it that whenever you make any type of noise, the deer always snaps it's head up and looks right at you. They never do that when being shot at. They are ducking and rolling away from the arrow.
"They are ducking and rolling away from the arrow."
How do they know to duck, if they don't see the arrow coming? Why don't they jump instead? Think about it. A deer ducks because it is reacting to the sound of the shot, and ducking, or crouching, is how they load up their rear legs to bound away. They can't bound away from a stiff legged position.
Matt
If there is no void how can they do faster thank the speed of gravity.
"But if the head is up, the deer can drop no faster than the sack. Gravity is a law that can’t be broken."
Yes.... and no. While its CG cannot drop faster than gravity I think there is some credence to to the deer dropping it's neck for (which can be done faster than gravity) and using that as some "mechanical advantage" to ducking the shot.
If it was as simple as the speed of gravity we can compensate for that. But it's not. A few years back (~2008) I had several doe working their way in from my left to right. It was getting dark and I quick lasered a tree they were going to pass. I thought it read 28 yards, turned out to be 20. Couple that with a steep downward angle I ended up with a high hit. On the opposite side. That deer dropped and spun 180 in the blink of an eye... still had the arrow in it on recovery or I would have never believed it.
lol if the deer uses mechanical advantage to drop it's neck faster than gravity than that means it's body will fall even slower than before. On a teeter totter when one side goes down the other side goes up. You can't have them both go down or both go up. I can't believe this stuff is being debated.
I've never shot loud broad heads because I agree with Rattling Junkie I think they are a big part of the problem. The smillisecond a loud arrow starts flying the noise is right there with the sound of the bow. Only it is coming closer. That I think is a way spookier issue for a deer than just the sound of the bow going off. It's the two together that cause a real problem. Drop something metal on your stand a deer won't even react as bad as when an arrow is coming its way. There's obviously something worse about the arrow than the pure one time noise. What is different?
One is a noise, and one is a noise associated with a projectile. Assuming they don't have a lot of experience with associating the sound of a bow with death, one can only assume it is the projectile causing the insane reaction. Then the question must be asked: "What is it about the projectile that scares them so much?" I think it has to be the fact that they can't see it, they don't know what it is, but they know it is coming, and fast.
GG,
I agree with what you wrote, but my point was that I think they are ducking the sound of the incoming arrow.
I find it hard to imagine how they are reacting to the sound of a broadhead. It's the crack of the release they are reacting to, IMO. And it's not just a straight drop. Sometimes it's a drop and pivot or a drop and roll. It's so fast you can't see it unless you film it and guys assume they F-d up when they didn't. It's happened to all of us and the only way to minimize it is to take a quartering away, or better yet - hard quartering away shot. Broadside shots are more risky, and quartering-to shots are extremely risky.
If they duck the sound of the incoming arrow, then wouldn’t they duck at any shot distance? I’ve shot several animals at longer distances that didn’t even flinch. I have to assume they were too far away to hear the shot, and they didn’t hear the arrow coming.
Matt
GG,. Yes, but not every animal ducks. Go watch as many YouTube videos and watch the reactions. You can tell on really long shots they still duck. Really think the second of the bow is going to cause that reaction at long range?
Pat,
Why does a deer that is ducking not ever snap his head up and look at the shooter? Any other noise you make, that is what they do.
^^ APauls is correct. He’s obviously passed a physics course somewhere in his travels.
The f=ma part of this is not debatable, but the topic of sound of arrow vs bow vs other sounds has me intrigued. I recently switched to a non-vented bh and vanes designed for cb bolts. Maybe I will have fewer coc-duckers as a result.
There are definitely different reactions to explain - and just when we think we’ve got it all figured out, we’ll see one do the opposite. :)
Devil, I still have to disagree. Like I said, I’ve shot many animals that didn’t even twitch a muscle before the arrow hit them. If they heard the arrow coming, they sure didn’t have time to react to it.
Matt
Many of these videos have the back end of the deer not really moving a whole lot. The chest dropping quite a bit. I can sit here and move my arm downward faster than gravity pulls it, because there are muscles that move my arm up and muscles that move my arm down. All muscles have an antagonist. It's not just gravity.
GG, that's cool, we don't have to agree, especially since nobody can prove either way what they are reacting to. It's an interesting conversation.
I'll admit that I am just guessing that a deer can hear the arrow only because I can hear every one and their hearing is a heck of a lot better than mine. Also, the arrow is making noise from displacing the air so it is already making noise before the arrow even leaves the string.
"lol if the deer uses mechanical advantage to drop it's neck faster than gravity than that means it's body will fall even slower than before. On a teeter totter when one side goes down the other side goes up. You can't have them both go down or both go up. I can't believe this stuff is being debated."
I said using it as *A* "mechanical advantage" doesn't mean it's a simpe lever. All kinds of "mechanical advantages". I use several different types in designing high speed cam driven automation systems. Body is a complex mechanism...ain't a see-saw.
It is an interesting topic, and I agree we've only scratched the surface of what we know about an animal's reaction to a bow shot.
Here's one I've often pondered. I assume many of you have been in stand when the hedge apples are dropping. If so, you know they can often make a loud sound when they hit the ground, or hit a branch on the way down. They inevitably make me jump, but the deer often seem oblivious to them, and don't react at all. Why do you think that is?
Matt
Grade 12 physics diploma should be a prerequisite to comment on this thread.
The body isn't a see-saw but where the neck meets the main body is essentially a fulcrum in this analysis. The musculature of a deer doesn't allow it to push it's chest down using it's ass or rear back muscles while it's neck is up. A deer too can quickly stomp its feet out-pacing the speed or gravity with its hoof like Vonfoust says.
But it can't stand there with its head in the air and somehow manage to sent its chest to the ground faster than gravity using it's ass muscles.
And finally, of course not every deer reacts the same. They all are different. There is no universal rule as to when a deer does and doesn't duck. Otherwise we'd know it by now. I believe the debate here is about what is most likely to make the deer duck.
I also think there is something to size, or hunting pressure. I honestly believe that deer in Canada, or Manitoba where I'm at duck a heck of a lot less than deer down south. Whether that is due to body size or hunting pressure I am not sure. The biggest deer (moose) obviously never duck. The next biggest (elk) almost never duck, but do sometimes. All the way to coues deer that apparently are like trying to shoot a dragonfly on meth.
A quiet longbow is only marginally more quiet than a Mathews compound. And, that’d be it and only possible if the longbow was shot without a quiver. To match that same Mathews compound.
My bows are the quietest they’ll get. And, I’ve sold bows without hesitation that I couldn’t reduce to a mere dull, very heavy but quiet thump. Both traditional bows and compounds. So, quiet is important. The most important thing to me.
Anyways, sometimes their tendency to move gets them in trouble. 22 yards. Dropped and spun when it heard the arrow coming.
Too late to the game I was now winning, he was going to take it somewhere. So, hindsight didn’t reveal much to him. But, he didn’t run anywhere.
FWIW, this was 100% true. And, it’s pretty dang funny too. I don’t care who you are.
Interesting topic whether it is bow noise, arrow noise, or both. Only way to prove is to film hunts where the bow hunter dry fires his bow instead of, releasing an arrow. Deer ducks, its bow noise. Deer doesn't could prove arrow noise. Costly to get a large enough sample to draw conclusion.
Is it possible they may even see the arrow coming at them? Or at least the fletching coming at them?
WV, your pic reminded me of my Father. He always shot his deer and elk in the neck with his rifle because he didn't want to waste any meat. ;-)
Once I shot a bull elk that had me busted at 40 yards. He was broadside and staring right at me. I think he reacted to the sight of my bow firing, rather than the sound. Or, he chose to bolt at the exact moment that I released. Which ever, he had spun a full 90 degrees by the time my arrow got to him. It ended up being a perfect Texas heart shot. The blood trail looked like it had been sprayed from a garden hose. I never realized how lethal that shot can be.
Matt
"The body isn't a see-saw but where the neck meets the main body is essentially a fulcrum in this analysis."
Yes, it's a Class 2 lever, more of a hinge than a static lever. And yes muscles, ligaments, joints keep the head and neck up.
"But it can't stand there with its head in the air and somehow manage to sent its chest to the ground faster than gravity using it's ass muscles."
Never said it did. Did you miss the part where the assumption is made that a deer throwing its head up may act as leverage in dropping the body. After designing liquid bulk trailers in the 80's, custom hoists and cranes for companys like Boeing and Lockheed in the 90's and high speed automation from 99 till now, I have a pretty decent grasp of statics, dynamics, mechanical motion, mechanical advantage in complex systems...
Matt,
That sounds like the doe I referenced above. My aim point is always low, at the shot, she switched ends and I hit her high, clipped the spine and liver, from the opposite side. That was with a 275fps 420gr arrow. Physics says that can't do that. Till they do.
Physics says that sound travels at 1100 fps, over 3 times faster than our arrows. So, it takes sound 0.10 seconds to travel 40 yards away. To get an idea how fast that is, I pulled my smartphone stop watch app up, then started and stopped it as fast as I can. My personal fastest time is 0.11 seconds, roughly the same time as the speed of sound covering 40 yards. Wow.
Matt
GreyGhost sound is even faster in water or metal. So don't drop stuff in the boat, but talking is fine as it's reflected off of the waters surface.
Tony, that’s exactly why I won’t buy an aluminum fishing boat. ;-)
If you think whitetails are fast, you should see Impala!! Dries Visser has a video demonstrating how much some antelope can move to educate incoming hunters. Lots of slo-mo vids and it is incredible.
The more I research this the more I am convinced that the sound of the arrow has a big influence on how a deer reacts. Ranch Fairy has a video where they have a mic about 10 yards in front of a shooter. The shooter shoots arrows from about 400 gr to 1000 gr with the same bow so that the energy is about the same but the arrow speed varies a lot along with the bow noise. It is easy to hear both the noise of the bow and the sound of the arrow in each shot. However, even at only 10 yards the bow noise is short whereas the arrow noise is long and just as loud. As the arrow weight goes up both the bow noise and the arrow noise drop noticeably. Arrow noise is exponentially related to speed. An arrow travelling at 300fps is going to be significantly noisier than one travelling at 240 fps. The deer hears the arrow noise start at the same time as the bow noise but the arrow noise gets louder as the arrow gets closer. With the mic at 20 yards and longer, I think that the arrow noise would be a lot more dominate. Watch that video and draw your own conclusions.
Back when I hunted with a 40# recurve and a heavy wood or aluminum arrow, I don't believe that the arrows made all that much noise going at 150 fps or less. Deer did not react to a shot like they do today. I think when they did react violently they actually were able to look up and see the arrow coming. The reactions being captured on video today are truly amazing.
Matt, I've often pondered about falling hedge (horse) apples and the lack of noticeable response by deer. Perhaps that the dropping apples are something they hear/have heard numerous time and just don't respond too the same way they do a muffled thud or loud whispering sound?
goyt for the win. You betcha they hear the arrow. Much more so than any bow made today.
Noise noise is irrelevant due to how quiet bows have become. But, you can take it to the bank no arrow is quiet. Not even close.
Interesting video. For many years now I've been saying that the maximum range for deer is 3 tenth of a second of flying time. so that means that if you shoot 180 fps , your max should 18 yards, for 300 fps , 30 yards . You get the idea. It hasn't failed yet for me. Quiet bows are hands down better any day, but I will always stick to my 3 tenth of a second of flying time for deer. Other animals react faster , and others do not react at all. As in squirrel vs racoon , you get the idea.
Juancho, if you apply flight time to squirrel reaction times, max range would be about 6 yards. At 300fps
This one is just like The Void. Just refuses to go away.
A deer CAN drop either end of its body at a rate faster than acceleration due to gravity because Muscles. Absolutely. But sometimes they do and sometimes they don’t, and sometimes they don’t even flinch ’til the arrow hits.
The question is really whether you can (or should) BANK on them ducking when you pick a spot.
I don’t. I haven’t hunted heavily pressured deer, so I have always picked a spot where I WANT to hit them and so far, so good…. On the not ducking part, at least. I’ve never seen more reaction than a slight crouch or freezing mid-stride, but it turns out I can shoot clean over them with no help at all.
To some extent I have to trust that my arrows are slow enough that if they TRY to duck, they’ll get away clean; if they move any direction but straight down, well, I guess it’s a box o’ chocklits and I’ll either get lucky or I’ll be screwed. Better hunters and better shots than I have done everything right and still had bad outcomes and I would have to be something special to think that it can’t ever happen to me just because it hasn’t…. Yet.
FWIW, I know a guy who has experimented with various loud noises and bow shots both AT deer and at angles away from them, and “his” deer only duck when he shoots AT THEM, so he’s in the camp that says they’re ducking the arrow itself, and he tries to get his arrows as quiet in flight as he can.
YMMV
