I almost feel foolish asking this question but my fascination for the octopus is far more advanced than my humble knowledge of it. I cannot seem to find the answer here. searching elsewhere online the common answer is eight but the diagram of the testes sac does not seem to support this. Also, the common belief is that the male reproductive system is in the head, which goes to show mass ignorance (including mine.lol), as opposed to the mantle. So how many testicles does a male octopus have anyways?