I found no references to use on animals. But there are not many animals holding their head on top of their spine, most wear it in front, walking on four legs. regarding "trolls": trolls are commenters who try to derail a conversation and try to get a raise out of people. They do not post genuine comments. Often they try to hurt and mock people. Or influence opinions for their own gain. It's cyber bullying really. We have no trolls in this conversation, we're all genuine people All view points and contributions are very much appreciated. Cricket's story was what made me cautious before I had the AP. I decided to take the risk but was well aware that I too might be plunged into chronical pain.