ascribed to baby Ankylosaurus two very small teeth that originate from the Lance and Hell Creek Formations and measure in length, respectively. The smaller tooth is heavily worn, leading Carpenter to suggest that ankylosaurids in general or at least the young did not swallow their food whole but employed some sort of chewing. Since adult Ankylosaurus did little chewing of its food, it would have spent less time in the day foraging than an elephant. Based on the broadness of the ribcage, the digestion of unchewed food may have been facilitated by hindgut fermentation like in modern herbivorous lizards, which have several chambers in their enlarged colon. In 1969 Austrian paleontologist Georg Haas concluded that despite the large size of ankylosaur skulls, the associated musculature was relatively weak. He also thought jaw movement was limited to up and down movements. Extrapolating from this, Haas suggested that ankylosaurs ate relatively soft non-abrasive vegetation. Later research on Euoplocephalus indicates that forward and sideways jaw movement was possible in these animals, the skull being able to withstand considerable forces. A 2016 study of the dental occlusion (contact between the teeth) of ankylosaur specimens found that the ability for backwards (palinal) jaw movement evolved independently in different ankylosaur lineages, including Late Cretaceous North American ankylosaurids like Ankylosaurus and Euoplocephalus. A specimen of the ankylosaur Pinacosaurus preserves large paraglossalia (triangular bones or cartilages located in the tongue) that show signs of muscular stress, and it is thought this was a common feature of ankylosaurs. The researchers who examined the specimen suggested that ankylosaurs relied heavily on muscular tongues and hyobranchia (tongue bones) when feeding since their teeth were fairly small and were replaced at a relatively slow rate. Some modern salamanders have similar tongue bones, and use prehensile tongues to pick up food. The retracted position of the nostrils of Ankylosaurus have been compared to those of fossorial (digging) worm lizards and blind snakes, and though it was probably not a burrowing animal, the snout of Ankylosaurus may indicate earth-moving behavior. These factors, as well as the low rate of tooth formation in ankylosaurs compared to other ornithischians, indicate that Ankylosaurus may have been omnivorous (eating both plant and animal matter). It may also (or alternatively) have dug in the ground for roots and tubers. Airspaces and senses In 1977 the Polish paleontologist Teresa Maryańska proposed that the complex sinuses and nasal cavities of ankylosaurs