The bold question-askers at What If use dinosaur battles to explore whether brains or brawn win out in nature’s arms race.

THE BRIDGE BOUNCED and car horns blared. Between the street corners below and the pedestrian bridge above, the spot where Treat Boulevard meets Jones Road in Walnut Creek was hopping Thursday evening.

A first-of-its-kind study traces the rise of ant- and termite-eaters, revealing how mammals returned to the evolutionary table — at least a dozen times — to hone traits for feasting on the social ...