Troodons size ranged widely. In general, individuals that lived further north were larger than those that lived in more southern areas. Troodons in Alaska were especially large, up to 12 feet long, 5 feet tall, and weighing up to 175 pounds. Meanwhile, Troodons that lived in more southern locations were only around 7 feet long, 3 feet tall, and weighed up to 50 pounds, about the size of a Velociraptor. Very likely Troodon had feathers, but no fossil evidence for feathers has yet been found. Arbour, V.M.; Burns, M. E.; Sissons, R. L. (2009). "A redescription of the ankylosaurid dinosaur Dyoplosaurus acutosquameus Parks, 1924 (Ornithischia: Ankylosauria) and a revision of the genus". Journal of Vertebrate Paleontology. 29 (4): 1117–1135. Bibcode: 2009JVPal..29.1117A. doi: 10.1671/039.029.0405. S2CID 85665879. My research and writing (including the material that appears here) is supported by the contributions I receive via patreon. If you value what I do, please consider supporting it here. Yes, some corvids [crows] and parrots are very smart (and crocodiles are much smarter than most people realise) so the *capacity* for high intelligence would appear to be there.

Troodontids had semi-manipulative fingers, able to grasp and hold objects to a certain degree, and binocular vision. [8] Russell proposed that his "Dinosauroid", like members of the troodontid family, would have had large eyes and three fingers on each hand, one of which would have been partially opposed. Russell also speculated that the "Dinosauroid" would have had a toothless beak. As with most modern reptiles (and birds), he conceived of its genitalia as internal. Russell speculated that it would have required a navel, as a placenta aids the development of a large brain case. However, it would not have possessed mammary glands, and would have fed its young, as some birds do, on regurgitated food. He speculated that its language would have sounded somewhat like bird song. [8][15] Did Dinosaurs and Pterosaurs 'Glow'? Extinct Archosaurs and the Capacity for Photoluminescent Visual DisplaysThe impact was immense, leaving a crater over 100 miles across and throwing huge amounts of debris into the atmosphere. a b Gilmore, C. W. (1932). A new fossil lizard from the Belly River Formation of Alberta. Transactions of the Royal Society of Canada, section 4, series 3 16:117-119 In 2011, Zanno and colleagues reviewed the convoluted history of troodontid classification in Late Cretaceous North America. They followed Longrich (2008) in treating Pectinodon bakkeri as a valid genus, and noted that it is likely the numerous Late Cretaceous specimens currently assigned to Troodon formosus almost certainly represent numerous new species, but that a more thorough review of the specimens is required. Because the holotype of T. formosus is a single tooth, this may render Troodon a nomen dubium. [5] Weil and Williamson, (2000). "Diverse Maastrichtian terrestrial vertebrate fauna of the Naashoibito Member, Kirtland Formation (San Juan Basin, New Mexico) confirms "Lancian" faunal heterogeneity in western North America." Geological Society of America Abstracts with Programs, 32: A-498.

Troodontids are known from both Asia and North America, the most complete specimens come from Upper Jurassic Strata of China, Lower Cretaceous strata of China (western Liaoning Province) and the Cretaceous of Mongolia. In contrast, troodontids from the western hemisphere, specifically Mexico, USA and Canada are very poorly known with a very fragmentary fossil record. Previously unassigned fossils from the lower part of the Dinosaur Park Formation have now been assigned to the resurrected troodontid species Stenonychosaurus inequalis. He focused on a lesser-known dino – Stenonychosaurus inequalis – which boasted a large brain, opposable fingers with a very human-like grip and stereo vision that was at least the equal of ours. a b Cullen, Thomas M.; Zanno, Lindsay; Larson, Derek W.; Todd, Erinn; Currie, Philip J.; Evans, David C. (2021-06-30). "Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation1". Canadian Journal of Earth Sciences. 58 (9): 870–884. doi: 10.1139/cjes-2020-0145. It’s not an essential or inevitable effect of evolution: elephants, dolphins, pigs and crows – those airborne descendants of the dinosaurs – are all impressively intelligent creatures that have never needed to make the leap to using technology.Stenonychosaurus (meaning "narrow claw lizard") is a genus of troodontid dinosaur from the Late Cretaceous Dinosaur Park Formation of Alberta, Canada, as well as possibly the Two Medicine Formation. The type and only species, S. inequalis, was named by Charles Mortram Sternberg in 1932, based on a foot, fragments of a hand, and some caudal vertebrae from the Late Cretaceous of Alberta. S. inequalis was reassigned in 1987 by Phil Currie to the genus Troodon, which was reverted by the recognition of Stenonychosaurus as a separate genus from the possibly dubious Troodon in 2017 by Evans et al. and also later in the same year by Van der Reest and Currie. Varricchio et al. (1997) described the exact structure of the nests. They were built from sediments, they were dish shaped, about 100 cm 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 imbedded 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. Stenonychosaurus teeth, however, are different from most other theropods. One comparative study of the feeding apparatus suggests that Stenonychosaurus could have been an omnivore. [16] The jaws met in a broad, U-shaped symphysis similar to that of an iguana, a lizard species adapted to a plant-eating lifestyle. Additionally, the teeth of Stenonychosaurus bore large serrations, each of which is called a denticle. There are pits at the intersections of the denticles, and the points of the denticles point towards the tip, or apex, of each tooth. The teeth show wear facets on their sides. Holtz (1998) also noted that characteristics used to support a predatory habit for Stenonychosaurus – the grasping hands, large brain and stereoscopic vision, are all characteristics shared with the herbivorous/omnivorous primates and omnivorous Procyon (raccoon). Their eyes were very large (perhaps suggesting a partially nocturnal lifestyle), and slightly forward facing, giving Stenonychosaurus some degree of depth perception. [5] Brain and inner ear [ ] Stenonychosaurus inequalis is known from the Dinosaur Park Formation of southern Alberta, Canada, which at the time was a warm coastal floodplain covered by temperate forests. Apex predators included tyrannosaurids such as Daspletosaurus and Gorgosaurus. Herbivores included hadrosaurids such as Lambeosaurus, Corythosaurus, and Prosaurolophus; ceratopsids such as Styracosaurus, Centrosaurus, and Chasmosaurus; ankylosaurs such as Scolosaurus, Euoplocephalus, and Edmontonia; and pachycephalosaurs such as Stegoceras and Foraminacephale.