Would you not say that for WHATEVER REASON, whether natural or unnatural, stress is counter-productive to health? (They say that about humans, too. We might be stressed from moving to a new home, a marriage, a birth, and though these are joyful occasions, that stress is _still_ considered harmful to our health). Yes, we know that some males are so frantic in their search for a mate, that they stop eating. Just the springtime search for a mate is stressful. Add to that the self-imposed cessation of regular feeding, for weeks or months. Add to that the stress of living with a competitor, for mates, territory, food, shelter- _that_ is unnatural. No stress is good stress.