Handicap principle
The 'handicap principle' was invented by Prof. Amotz Zahavi from Tel Aviv University. It claims to explain the fact that some animals have characteristics that do not necessarily help them survive. Lets take the peacock for example. The peacock's tail is long and heavy and actually diminishes its chances to survive. The mature male she found was strong enough to survive even though it had a long tail and therefore it is probably stronger than the average peacock.