LOS ANGELES, CA (AP).- With a dental pick in hand, Karin Rice delicately scraped off a clump of asphalt from a pelvic bone belonging to a horse that roamed Los Angeles tens of thousands of years ago. Like many unsuspecting creatures of the last Ice Age, the horse probably stopped to take a sip of spring water only to be ensnared — and later preserved — in a pool of sticky asphalt that seeped from underground crude oil deposits. “You’re opening up this ancient world and getting to look back in time,” Rice said during a recent dig at the La Brea Tar Pits in the heart of Los Angeles. For the past three years, scientists have been sifting through a significant trove of bones and a nearly intact mammoth skeleton discovered in 2006 during the construction of an