Animal rights activists in Austria, knocked back by a lower court in trying to get a 26-year-old chimpanzee - Pan - classified as a person, will be taking their challenge to the country's Supreme Court. They need a better case than the one stated here by the president of their group, the Association Against Animal Factories (AAAF). He 'insists that Pan is "a being with interests"'. But this would only make him a person if there were no non-persons with interests. Just about any sentient being can be said to have interests - for example, an interest in not being caused pain. I don't propose to go into what are the necessary and sufficient conditions of personhood, but some of these would be relevant: capacity for deliberation and choice, rationality, self-awareness, autonomy, and moral sense.
Whether or not a good case can be made for Pan being a person, if the law really doesn't recognize any category intermediate between a person and a thing - as the AAAF are reported as saying - then it should do. (Via Memeorandum.)