The freezer method is usually what people suggest as being humane and painless. Of course, if you think it through, it is probably pretty painful (or at the minimum - VERY uncomfortable).
Since these animal are exothermic freezing is not a bad route to go, but you will be moving a fully alert animal from the relative temperature of a jungle to the climatic temperature of the Arctic. Ever take a cold shower? Yes? Now imagine that with ice water - same thing. These animals DO have pain and temperature receptors in their skin.
Yes, they will eventually "go to sleep" and then die from the cold in the freezer. It would be much more humane to cool them down to that state of stupor/sleep BEFORE introducing them to the freezer.
The best way to do that is to place the snake into a RubberMaid or Tupperware container and place that container into your refrigerator for a couple hours. After that, the snake should have slowly cooled down enough to be in that stupor/sleep state that people talk about that makes freezing humane. THEN place the whole container (with lid obviously) into your freezer.
People talk about just placing the snake into a zip lock bag. This essentially would be like laying in the snow naked since there is essentially nothing to separate the snake's skin from the frozen surfaces of the freezer. The advantage of using the TupperWare/Refrigerator method is that the air trapped within the container slowly cools down allowing the animals natural body chemistry and metabolism adequate time to adjust to the temperatures and place the snake into the desired (and ultimately more humane) stupor.
Look at it this way: fish are also exothermic. But would you purchase a fish from the pet store and immediately dump it into your tank when you got home? No. You would shock it's system regardless of whether the ambient water temperature of your tank was warmer or cooler than the body temperature of the fish. Instead, to avoid shock and to allow the fish's body time to adjust you would place the entire plastic bag that you carried the fish home in into the tank of water and allow the bag's water time to warm up or cool down to the temperature of the water in the tank.
People tend to forget (or they simply do not realize) that metabolism - even in exothermic animals- is a biochemical process as much as it is a process that relies on external temperatures. Since it is a biochemical PROCESS it does take time for the animal's body to enter and exit the various stages of alertness. This is why you see snakes basking in the sun for (sometimes) hours at a time - it takes time for them to warm up to "full alert mode" - the same is true for cooling them down to enter the "sleep/stupor mode".
After this, I really hope I don't see too many more posts that claim putting an 80-90 degree animal directly into a below freezing environment is "humane". In the end, it IS a humane way to euthanize them, however, it is the LAST STEP in the process - not the ONLY step.
[Brandon steps down from soap box and exits stage right.]
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Stay United!
I'm still not sure if it's weird that my best friend is a two year old boa named Ronin. He's quiet, non-judgemental and listens... what more could you want?
