Whales, dolphins and other cetaceans underwent numerous physiological changes as they transitioned from the land to the sea. (Credit: Carl Buell, John Gatesy)

Life began in the oceans, and for hundreds of millions of years, that’s where it stayed. It took our deep ancestors eons to crawl, flop and gasp their way onto land. It turned out to be a pretty good decision, all told, as those creatures found a brand new world to inhabit. The ancient pioneers eventually led to mammals, including us —