By way of his recent attempt to contrast the hard and "woolly" sciences, Beverly Haistead (The Scientist, December 15, 1986, pp. 12-13) posed the question of how to account for surviving species in the face of Alvarez's asteroid impact hypothesis of dinosaur extinction. We would like to suggest an alternative interpretation of the demise of dinosaurs based on a unique psychological capacity in many animal forms today.

Tony Swain has called attention to the fact that during the Cretaceous period there were important changes in the composition of flora, including the relatively rapid rise of flowering angiosperms (see "Morphology and Biology of Reptiles" in Linnean Society Symposiums Series 3, 1976). He hypothesized that the ability of flowering plants to produce hydrolysable tañnins as deterrents to their consumption and the appearance of toxic alkaloid angiosperms may have had a deleterious effect on the large herbivorous dinosaurs.

As an...

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