Handicap principle facts for kids

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. Let's take the peacock for example. The peacock's tail is long and heavy and actually diminishes its chances to survive. So why did it evolutionarily survive? According to the principle, one day, a mutant peahen that likes peacocks with longer tail, looked for a male with this characteristic. 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. Therefore, its predecessor males are going to be stronger and also to have a long tail while the newborn females are going to like long tails, passing the ideals of the principle to the next generations.

This principle comes in addition to the well-known adaptation part of evolution theory claiming that the one who fits best to its environment survives.

Images for kids

• 

  The peacock tail in flight, the classic example of a handicapped signal of male quality

• 

  Johnstone's 1997 graphical representation of a Zahavian handicap. Where C_L is cost to a low-quality signaller and C_H is cost to a high-quality signaller. Optimal signalling levels are S^*_L for a low-quality signaller, and S^*_H for a high-quality signaller.

• 

  Luxury cars and other "Veblen goods" may be an example of the handicap principle in humans

• 

  Impala stotting, a behavior that may signal to predators that a pursuit would be wasted

See also

In Spanish: Principio del handicap para niños