Before they got all cute, our tuxedoed friends were downright imposing. Researchers have discovered fossil remains of a five-foot-tall, seven-inch-beaked penguin [right] that waddled its weight around roughly 40 million years ago in what is now Peru. Its size and that of a second new penguin from that time [left]¿compared with the only existing Peruvian penguin [center]¿complicates paleontologists' usual assumption that animals shed heat-trapping pounds when they move to warmer climates, the discoverers wrote in a paper published online this week by Proceedings of the National Academy of Sciences USA.