Tracking a deer or other animal shot with an arrow can be difficult. It is dissappointing for many reason not to find your kill after you have wounded it.
I propose to have an arrow with a liquid filled shaft that leaks it's contents out the rear end of the arrow after impact. The impact of the arrows tip with a object forces an internal rod to shatter a sphere at the feather end of the arrow, allowing the contents to weep out at a controled rate due to the tiny drip valve there in.
If the arrow is inlodged at an upright angle (tip down) the running of the animal provides the arrow with a whipping back & forth action that forces the liquid up and out.
The liquid has unique qualities: shows up extremely well under black light; so put a black-light in your flash light and go. It also has a unique, controled odor, so you could train a dog to track this smell, rather than trying to have the dog get the animals scent.-- macncheesy, Nov 11 2008 - or the arrow could have a smoke generator in it-- hippo, Nov 11 2008 One could have some explosive inside the arrow also. A animal that went a long way could be located by the sound of the detonation. This would also help finish off an animal which remained too lively, while not impacting the bowhunters desire for sport.-- bungston, Nov 11 2008 What if the animal keeps going after the liquid runs out? Perhaps use a hollow arrow that leaks the animals blood itself down the tube?-- Mony a Mickle, Nov 14 2008 My total opposition to all animal killing = [-]. //animals scent// (punctuation - animal's)-- xenzag, Nov 14 2008 How do you feel about talking about killing animals, or thinking about killing animals, or writing about killing animals, but not actually killing animals? Just chewing the fat..-- Mony a Mickle, Nov 14 2008 xenzag, I have halfbaked up a blunt tipped arrow for you such that it will strike the deer and leave a letter X on its fur, but not kill it. Now have all the fun of hunting, but without the killing! Added bonus - you can hunt the same animal all day long.-- bungston, Nov 14 2008 I was wondering the other day about whether a small enough GPS transponder could be made that wouldn't effect an arrows center of gravity. Not only would you be able to find your wounded critter but your lost arrows as well. (+)-- 2 fries shy of a happy meal, Nov 14 2008 I'm pretty sure you couldn't get a liquid filled arrow to behave. I don't think you understand just how much goes into "tuning" arrows for good flight. There are several commercial products available for this purpose, however.
First, you can get illuminated nocks - the nock is the rearmost part of the arrow that engages the string. These "luminocks" are mostly for night shooting, but certainly let you know where the arrow went, and can aid tracking.
Second, there is a product out there that basically trails a very thin (but apparently strong) string, which you then follow back to your arrow after the shot.
All this assumes you didn't get "pass through" - which pretty much any adequately powered bow/adequately sharp broadhead/adequately aimed shot should produce anyhow.
Lastly - I don't approve of supplying tools to perpetuate bad hunting practices. Get your shots right or don't hunt. Take reasonble shots with high percentages for swift, humane kills or don't bow hunt. period.-- Custardguts, Sep 28 2009 random, halfbakery