I am wondering why it is τους εαυτούς τους and not τα εαυτά τους, since animals are neuter. The pronoun changes, του, της, τους but the εαυτός seems to only change in number but not in gender? Can someone explain?
The self referring pronoun is "ο εαυτός+___", regardless of the subject's (grammatical or otherwise) gender: masculine and neutral is "ο εαυτός του", feminine is "ο εαυτός της". Full case/numbers table here, search for "Αυτοπαθείς αντωνυμίες" (Paragraph 5.3).