What do you do with a rat that bites?

There is a thought that thoracic compression actually is death by compressing the heart, and therefore stopping blood flow. Some researchers have noted that unconsciousness occurs within ten seconds, which is too rapid for suffocation, even in rodents. The AVMA doesn't like it though, mainly because nobody has actually examined the true cause of death. If it's death via the heart stopping, AVMA would probably be alright with it. If it's death via suffocation, AVMA is definitely against it. Because they're not sure, the AVMA takes the conservative stance and doesn't endorse thoracic compression as an acceptable form of euthanasia. However, field mammalogists through the American Society of Mammalogists (myself included) recognize thoracic compression as the most efficient and arguably humane way of quickly reaching unconsciousness before death. In fact, thoracic compression induces unconsciousness more rapidly than carbon dioxide over exposure, which is what most folks use to euthanize rodents.

Granted, carbon dioxide over exposure is far more efficient if you're euthanizing many animals at once, but for small collections, thoracic compression works fine and doesn't require any additional equipment.