Saving an endangered animal is an important task conservationists undertake. We understand that protection of the animal and/or its habitat is the key factor in this context. But a recent attempt to save the Kakapo, a near-extinct ground dwelling parrot of New Zealand involves more than this. It is a triumphant confirmation of the theory formulated by Trivers and Willard more than three decades ago Science 179 90, [1973]. They argue that 50:50 male-female ratio in mammals and birds will be altered by natural selection depending on the physical condition of the mother, food availability and such external, non-genetic factors.
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