Decapitation
is often times recommended as a humane and easy way to euthanize reptiles.
Unfortunately, research indicates that this may not be the case. Clifford
Warwick discusses it in Reptiles: Misunderstood, Mistreated and Mass-Marketed
(1990; Nower Productions, UK). There are no references given in this booklet
written for the carriage trade, but, as a biologist of some note, Warwick
has written extensively on ethological* aspects of reptiles and using
ethology to identify illness and stress in captivity.
"Some of the
many ways in which reptiles are "killed" are mentioned later
on but one method which is quite commonly used is decapitation. Generally
speaking, in mammals and birds, for example, quickly severing the head
from the rest of the body may cause immediate or near immediate loss
of consciousness and a very rapid death. It might not be describable
as 'humane' but the period of post-severance life in the head is almost
certainly short. Although meaning certain death, decapitation is certainly
not a rapid or humane way of killing reptiles. As hard to believe as
it seems, the heads cut from reptiles live on well after the horrific
event of decapitation itself. It is not a case of "nerves causing
the head to move unconsciously" as most people think. The heads,
and parts of the neck if still attached, are alive and some may attempt
to bite objects which approach; the eyes may follow movement and the
pupils contract and dilate in response to light and dark; they can blink
and in the case of snakes and lizards, flick out and in their tongues
to test the air for scent and even move slightly if enough of their
neck is left.
"With what movement
they can manage they often writhe in agony from the massive severance
of tissue. They are virtually helpless, frightened and going to die.
If it seems too inconceivable to be true, then think of it as being
a case of animals which have had most of their bodies cut away. One
might think that suffering of this kind could not be endured for long.
If only that were true. Unfortunately, a problem associated with the
reptilian metabolism's ability to operate at relatively low oxygen and
low blood pressure levels is that nerve tissue is, to put it simply,
very tough. Therefore, the nervous system, which of course includes
the brain, can function away from the rest of the body for some time.
In fact, the activities of decapitated heads mentioned earlier have
been recorded as present for around an hour or so. If reptiles are to
be killed by physical means (rather than by, say, an injected overdose
of an anesthetic), then it has to involve complete and rapid destruction
of the brain; otherwise they are very likely to suffer enormously and
for a long time before dying."
Other references relating
to decapitation include several in Frye (Reptile Care: An Atlas to
Diseases and Treatments), and in Manual of Reptiles, the
latter of which states:
"Decapitation
should not be used as a sole method of euthanasia, unless the brain
is destroyed by pithing immediately afterwards (Cooper et al, 1984).
The assumption that decapitation results in unconsciousness followed
by a rapid deterioration of the nervous system is disputed: the brain
remains viable for up to an hour (Cooper et al, 1984).
Freezing is also often
recommended as a method of euthanizing reptiles and other animals. In
Manual of Reptiles, Lawton cites Cooper JE, Ewbank R, Platt C,
and Warwick C. (1989, editors, Euthanasia of Amphibians and Reptiles,
Universities Federation for Animal Welfare, Potters Bar), in regards to
the painful formation of ice crystals in tissues and on skin, thus precluding
hyperthermia as a method of euthanasia.
Frye states that pure
carbon dioxide as a method of euthanizing reptiles is not acceptable as,
while it induces a state of narcosis, the ability of many reptiles to
endure prolonged anoxia (absence of oxygen) precludes death.
*ethology: The scientific
and objective study of animal behavior especially under natural conditions.
Additional
Reading
Other articles
by Warwick I have found insightful:
Warwick, C. 1990. Important
ethological and other considerations of the study and maintenance of reptiles
in captivity. Applied Animal Behaviour Science 27(4):363-366.
Warwick, C. 1990. Reptilian
ethology in captivity: Observations of some problems and an evaluation
of their aetiology. Applied Animal Behavior Science 26:1-13.
Ethology,
Ecology and Critical Anthropomorphism
Pain
and Analgesia in Herps
Related Articles
Euthanasia
of Reptiles
AVMA
Panel on Euthanasia, 2000
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