"The pessimist sees difficulty in every opportunity. The optimist sees the opportunity in every difficulty." - Winston Churchill

Supplementary material

The impact of an asteroid 10km in diameter, 65 million years ago, marks the transition between the Mesozoic and the Cenozoic (or between the Cretaceous and the Tertiary if we focus on periods rather than eras). The ensuing climate changes seem to have dealt a fatal blow to the great dinosaurs who had dominated the world's fauna for tens of millions of years before the event; the great beasts would soon be exctinct.

Among the vertebrate land-dwelling survivors were several types of non-dinosaurian reptiles (crocodiles, snakes, lizards, chelonians, the lone tuatara); many descendants of dinosaurs, now feathered and warm-blooded, the birds; and especially (in our homocentric view) a clade born of the synapsids, the mammals. As was the case for the birds, the mammals' ability to regulate their temperature may have played a very important role in their surviving the Cretaceous/Tertiary extinction event.

But mammals were not spunky newcomers in the game of life; their earliest fossils go back 220 millions of years, barely a few million years younger than the earliest dinosaurs. It just seems that they could not gain the dominance they were to know later on as long as the formidable great reptiles were around.

Which means that deriding someone or something who has passed their prime by calling them "dinosaur" is a bit silly, really. If dinosaurs were still around, I bet they'd be setting the agenda instead of those annoying (but delicious) mammals.