I have worked at medical device companies for most of my career. I have been present in a good number of animal studies, and I don't like seeing them. It is important that you know that the animals are treated as humanely as possible, and there are strict regulations around their treatment in the USA. I consider animal studies to be a necessary evil. Without these studies we would not have modern medical devices or pharmaceuticals. The fact that people can live so long and have healthier lives, compared with the past, is directly due to these devices and pharmaceuticals, and indirectly due to the animal studies. Nothing in life is perfect, but the fact that I'm working to help many people outweighs, by quite a bit, my dislike of animal studies.