Human fetuses are clever students, able to distinguish male from female voices and the voices of their mothers from those of strangers between 32 and 39 weeks after conception. Now, researchers have demonstrated that the embryos of the superb fairy-wren (Malurus cyaneus, pictured), an Australian songbird, also learn to discriminate among the calls they hear. The scientists played 1-minute recordings to 43 fairy-wren eggs collected from nests in the wild. The eggs were between days 9 and 13 of a 13- to 14-day incubation period. The sounds included white noise, a contact call of a winter wren, or a female fairy-wren’s incubation call. Those embryos that listened to the fairy-wrens’ incubation calls and the contact calls of the winter wrens lowered their heart rates, a sign that they were learning to discriminate between the calls of a different species and those of their own kind, the researchers report online today in the Proceedings of the Royal Society B. (None showed this response to the white noise.) Thus, even before hatching, these small birds’ brains are engaged in tasks requiring attention, learning, and possibly memory—the first time embryonic learning has been seen outside humans, the scientists say. The behavior is key because fairy-wren embryos must learn a password from their mothers’ incubation calls; otherwise, they’re less successful at soliciting food from their parents after hatching.