Skye12_
Did Hisoka even explain to Rhydon why he was training him? There's no mention of that and I think it's an important point to make to someone who possibly has never experienced actual danger or had anyone they cared about who could be exposed to danger. Danger of starvation doesn't count here. I doubt that Rhydon knows he can starve to death and probably just doesn't like the feeling of hunger. He hasn't experienced feeling of threat of death and/or pain upon himself and/or his friends.