The answer to this question is that while dogs and humans share many of the same organs, the appendix does not exist in dogs. The appendix is an organ that is found in both humans and some other animals (such as horses and pigs), but it is absent from most dogs. This difference likely stems from Evolutionary biology. The appendix is a vestigial organ that has been lost in various species of animals over time because it doesn’t have any real purpose or function.