Occasions arise when the only way to alleviate pain and suffering is to humanely euthanize captive herps. These may include irreversible illness or injury, sacrificing a small number of a larger group to diagnose a disease outbreak or culling an overcrowded collection. Many prey animals, especially rodents, are euthanized prior to feeding them to captive reptiles. This is a special circumstance in that chemical agents should not be used or the reptile eating the euthanized rodent could suffer toxic affects. When euthanasia is performed it must be performed in a humane manner.
Decapitation is an easy way to kill a reptile in that no special equipment or drugs are necessary.
Nevertheless, the brain of a decapitated reptile may remain active for up to an hour, so decapitation by itself is inhumane. It may be used if the brain is pithed, or destroyed by the insertion of a probe, immediately afterwards. Some of you may have pithed leopard frogs in high school biology prior to their dissection. Euthanasia can be done by destroying the brain with a sharp blow to the head, on the middle and just posterior to the eyes. This can be done in an emergency, as when an animal is found hit by a car, grievously injured but not yet dead and no other method is available.