In sleep, we are birds of a feather
Did you sleep like a baby last night? You might think so, but actually you slept like a bird. Or rather, a bird slept like you. One bird, in particular — the zebra finch, which researchers say has a sleep structure very much like that of people and other mammals. Philip Steven Low of the Salk Institute for Biological Studies in San Diego, California, and colleagues report in The Proceedings of the National Academy of Sciences that electroencephalograms of the songbirds show they have episodes of rapid-eye-movement sleep and slow-wave sleep as well as transition stages and quick spikes, all reminiscent of mammalian sleep patterns. It’s the first time that this complete group of sleep characteristics has been found outside of mammals—a surprising finding, Dr. Low said, because birds lack a neocortex, the part of the mammalian brain thought necessary for such patterns.