DINOSAURS. In geological terms, the dominant animal species on Earth. Their reign, unchallenged for over 160 million years, is some twentyfold in excess of even the most charitable estimate of the entire span of human evolution and was only moderated—not terminated—by an extinction 65 million years ago that otherwise destroyed most terrestrial life. Owing to incredible genetic diversity, their avian descendants have not merely survived but now number in the hundreds of billions.

The word “dinosaur” is also used non-zoologically as a term of derision, implying that one is slow, sluggish, stupid, ridiculously massive, unable to adapt, bound for extinction, or (in the language of birds) a human.

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