Sixty-six million years ago, a rock 6 to 9 miles wide struck the Yucatan peninsula, causing most life on earth to cease. The CretaceousâPaleogene (KâPg) extinction event wiped out three-quarters of all species, including most four-legged animals weighing over 55 pounds.
In an instant, being large was suddenly a disadvantage. In a moment, being a giant dinosaur was out, and small birds and mammals had the upper hand. The world was suddenly different, and now being small, agile, and open to change was now en vogue.
