a predatory habit for Stenonychosaurus – the grasping hands, large brain, and stereoscopic vision – are all characteristics shared with herbivorous or omnivorous primates and omnivorous Procyon (raccoon). Age determination studies performed on the Two Medicine troodont using growth ring counts suggest that this dinosaur reached its adult size probably in 3–5 years. A partial skeleton has been discovered with preserved puncture marks, possibly inflicted by a predator. Reproduction Dinosaur eggs and nests were discovered by John R. Horner in 1983 in the Two Medicine Formation of Montana. Varriccho et al. (2002) have described eight of these nests found to date. These are all in the collection of the Museum of the Rockies and their accession numbers are MOR 246, 299, 393, 675, 676, 750, 963, 1139. Horner (1984) found isolated bones and partial skeletons of the hypsilophodont Orodromeus very near the nests in the same horizon and described the eggs as those of Orodromeus. Horner and Weishampel (1996) reexamined the embryos preserved in the eggs and determined that they were those of Troodon, not Orodromeus. Varricchio et al. (1997) made this determination with even more certainty when they described a partial skeleton of an adult Troodon (MOR 748) in contact with a clutch of at least five eggs (MOR 750), probably in a brooding position. Van der Reest and Currie considered it possible that the Two Medicine troodont was the same species as Stenonychosaurus. Varricchio et al. (1997) described the exact structure of the nests. They were built from sediments, they were dish shaped, about in internal diameter, and with a pronounced raised rim encircling the eggs. The more complete nests had between 16 (minimum number in MOR 246) and 24 (MOR 963) eggs. The eggs are shaped like elongated teardrops, with the more tapered ends pointed downwards and embedded about halfway in the sediment. The eggs are pitched at an angle so that, on average, the upper half is closer to the center of the nest. There is no evidence that plant matter was present in the nest. Varricchio et al.(1997) were able to extract enough evidence from the nests to infer several characteristics of troodont reproductive biology. The results are that they appear to have had a type of reproduction that is intermediate between crocodiles and birds, as phylogeny would predict. The eggs are statistically grouped in pairs, which suggests that the animal had two functional oviducts,