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Amotz Zahavi (born 1928 in Petach Tikva, Israel) is an Israeli evolutionary biologist from Tel-Aviv University, and one of the founders of the Israeli Society for the Protection of Nature.

He is best known for his handicap principle, first published in 1975, which explains the evolution of characteristics, behaviors or structures that appear to reduce fitness and endanger the organism. The explanation is that these characteristics evolved by sexual selection as a signal of the status of the organism. This can be of use in attracting mates, among other things.

For example, the tail of a peacock makes the peacock more vulnerable to predators, and is therefore a handicap. But the message that the tail carries to the potential mate peahen is 'I have survived in spite of this huge tail, hence I am fitter and more attractive than others'.

Another example is "stotting," a sort of hopping that certain gazelles do when they sight a lion. As this behavior gives no evident benefit and would seem to waste resources, it was a puzzle until handicap theory offered an explanation. According to this analysis, the gazelle invests of bit of energy to show the lion that it had the fitness necessary to avoid capture, thus avoiding spending the energy required to evade actual pursuit. The lion would recognize that it could not catch this gazelle and so avoid a wasted pursuit.

Amotz Zahavi is married to the biologist Avishag Zahavi.

• Zahavi, A. (1975) Mate selection - a selection for a handicap. Journal of Theoretical Biology. 53: 205-214.
• Zahavi, A. (1977) The cost of honesty (Further remarks on the handicap principle). Journal of Theoretical Biology. 67: 603-605.
• Zahavi, A. and Zahavi, A. (1997). The handicap principle: a missing piece of Darwin's puzzle. Oxford University Press. Oxford. ISBN 0-19-510035-2