Freezing reptiles as a form of euthanasia

[The following appeared in the December 2006 issue of the PNHS newsletter as part of the "Ask the Dr" column.]

Dear Doctor Maas,
My snake has been sick with a respiratory infection for several years. I have taken him to a couple of vets, who look at him and each time put him on several different antibiotics. A couple times he has gotten better for a brief period of time but then the infection returns. At this point, he has lost a lot of weight from not eating and moves about very little. I think he is suffering, and think he should be put down. I was told that I could put him in the refrigerator or freezer and chill him down to the point that he dies. This sounds awful, but was told this was the best way to put him to sleep. What do you think?

- Not Ready to Ice Him.

Dear Ice,
You are very correct: Chilling a herp to death is an awful way to die, and, could they speak, they would describe it as torture. The American Veterinary Medical Association and the American Association of Zoological Veterinarians classify this as cruel treatment of animals and animal abuse and the Association of Reptile and Amphibian Veterinarians categorize it as an unacceptable method of euthanasia, as well. If a veterinarian recommended this to you, it could be categorized as malpractice.

Unfortunately, the myth that freezing herps is a good way to put them down persists. It almost makes sense, being that reptiles and amphibians are “cold-blooded”, but in fact, this adaptation makes this procedure even worse for them. This is because as they get cold, they become torporous, that is, alert mentally but unable to move or respond. This is in contrast to mammals, which become unable to move, but also become mentally dull and comatose as they become hypothermic. As a result, reptiles and amphibians can feel their body get cold, which produces pain, but they can do nothing about it. Studies show that they can, literally, feel their cells freeze and rupture as they get further chilled, sensing pain as intensely as if they were being burned alive, but unable to move or respond.

What defines an acceptable method of euthanasia? Simply put, it must be a method that provides a safe, painless form of death. Additionally, it should be quick and effective, not allowing the animal to suffer either mentally or physically. The most common and accepted form is a single intravenous injection of sodium pentobarbital, an anesthetic drug that when given at an overdose amount, stops the brain, heart and lungs. Alternative methods include rapid decapitation (this must take less than 1/10 of a second to be painless, such as with a cleaver or sharp axe), pithing, or exsanguination. The latter two of these require pre-euthanasia anesthesia to prevent suffering, and it is recommended for the first, as well.

In summary, cooling or freezing reptiles and amphibians to kill them is unacceptable, cruel and painful. I cannot recommend or advocate it, and I would like very much to eliminate this technique from all herpers’ vocabulary, for the sake and respect of the animals.

As a parting note, I would like to pay attention to the first part of your letter; the portion referring to the previous medical care of your animal. I understand your frustration with the fact that you have taken your snake to veterinarians with a lack of success of treatment. It sounds from your brief description that perhaps no definitive diagnosis was ever reached. The only advice I can offer is that you would not accept a lack of accurate diagnosis and definitive treatment for your dog, so why should you accept it for your snake, who is no less a pet and dependant on you for its survival and well-being? And just as you would not go to a podiatrist for an eye problem, treating a reptile or amphibian is different than treating a dog, cat or horse, and every responsible herper should seek out specially trained veterinarians who have invested both the time to learn the unique medicine required to treat these species, and the money necessary for the specialized equipment to administer therapy. The yellow pages and web are both good initial resources to find such a vet, but even better is to contact your local herpetological society, breeders and fellow herpers for recommendations. Additionally, the American Association of Zoological Veterinarians and the Association of Reptile and Amphibian Veterinarians both maintain lists on their websites of member veterinarians who may also be qualified to help. Lastly, do not ever be afraid to quiz a potential veterinarian as to their experience, training and skills before hiring their services.

Best wishes to you, and my condolences to you with the failing health of your snake. Always remember, though, that where there is life, there is still hope. Please do not think that automatically there is no hope of recovery, but that perhaps with appropriate diagnostics and treatment your pet may heal.

Happy herping,

Adolf Maas, DVM

[Dr Maas' vet practice contact information is available from our Vet page]