Paleontologists in Montana have unearthed an ancient, sediment-filled burrow that holds remains of the creatures that dug it. The find is the first indisputable evidence that some dinosaurs maintained an underground lifestyle for at least part of their lives.
Oryctodromeus cubicularis, which, in Greek, means "digging runner of the lair." They reported their find at the recent meeting of the Society of Vertebrate Paleontology in Austin, Texas.
Varricchio, D., A. Martin, and Y. Katsura. 2007. Burrowing behavior in a new ornithopod dinosaur from the mid Cretaceous of Montana. Society of Vertebrate Paleontology meeting. Oct. 17-20. Austin, Texas. Also in Journal of Vertebrate Paleontology, 27 [Supplment to No. 3): 162A.Thanks to Sukie C!