Dinosaur voice box reveals birdlike sounds.

An 80 million-year-old fossilized voice box belonging to an armored dinosaur, Pinacosaurus grangeri, was discovered in Mongolia in 2005. A new analysis suggests that the creature's vocalizations may have been far more subtle and melodious than its previously assumed crocodilian grunts, hisses, rumbles, and roars. The researchers found that P. grangeri had a very large cricoid and two long bones that were used to adjust its size, turning the P. grangeri voice box into a vocal modifier. This anatomical setup likely meant that the ancient herbivore was capable of making a large array of sounds, including rumbles, grunts, roars, and possibly even chirps.