Why are dinosaurs extinct? You asked Google – here’s the answer | Brian Switek

Every day, millions of internet users ask Google life's most difficult questions, big and small. Our writers answer some of the commonest queries

Let's clear something up right away. Dinosaurs aren't extinct. Not entirely. Every magpie, pigeon, penguin, and ostrich alive today - every single bird - is a dinosaur. They're all descendants of small, toothy, feathery dinosaurs that hopped and fluttered around from the Jurassic era onwards, meaning that birds are dinosaurs in the same way that bats are mammals. The Archaeopteryx laid out under glass at London's Natural History Museum was the first of its ilk, and the only reason today's birds seem so different is because the last of their close dinosaurian relatives trailed off into extinction about 66 million years ago.

But why did the most spectacular dinosaurs become extinct? Why don't we have to worry about descendants of velociraptor tipping over garbage cans, and why can't I feed a baby sauropod at the petting zoo? What happened to all those dinosaurs that inspire our dreams and fuel our nightmares?