10 Facts About Troodon

How Much Do You Know About Troodon?

London Natural History Museum

Troodon is often touted as the world's smartest dinosaur, but this both exaggerates this carnivore's intelligence and plays down its other, equally intriguing attributes. In the following slideshow, you'll discover 10 fascinating facts about this late Cretaceous theropod.


Troodon Is Greek for "Wounding Tooth"

Joseph Leidy's illustration of Troodon's teeth (Wikimedia Commons).

The name Troodon (pronounced TRUE-oh-don) derives from a single tooth discovered in 1856 by the famous American naturalist Joseph Leidy (who thought he was dealing with a small lizard rather than a dinosaur). It wasn't until the early 1930's that scattered fragments of Troodon's hand, foot and tail were unearthed, and even then, these fossils wound up being assigned to the incorrect genus (for more on this subject, see How Was Troodon Discovered?).

Troodon Had a Bigger Brain than Most Dinosaurs

Wikimedia Commons

The most notable feature of Troodon was its unusually large brain, which was heftier, in proportion to the rest of its 75-pound body, than the brain matter of comparably sized theropods. According to one analysis, Troodon had an "encephalization quotient" several times that of most other dinosaurs, making it the true Albert Einstein of the Cretaceous period. (Let's not get carried away, though; as brainy as it was, Troodon was still only about as smart as a chicken!)

Troodon Flourished in Colder Climates

Taena Doman

As well as a bigger brain, Troodon possessed larger eyes than most theropod dinosaurs, a hint that it either hunted at night or needed to gather in all the available light from its cold, dark North American environment (another dinosaur that pursued this evolutionary strategy was the big-eyed Australian ornithopod Leaellynasaura). Processing more visual information necessarily entails having a larger brain, which helps to explain Troodon's relatively high IQ.

Troodon Laid Clutches of 16 to 24 Eggs at a Time

A clutch of Troodon eggs (Wikimedia Commons).

Troodon is famous for being one of the few carnivorous dinosaurs whose parenting routines are known in detail. To judge by the preserved nesting grounds discovered by Jack Horner in Montana's Two Medicine Formation, Troodon females laid two eggs per day over the course of a week or so, resulting in circular clutches of 16 to 24 eggs (only a few of which would have escaped being eaten by scavengers). As with some modern birds, it's possible that these eggs were brooded by the male of the species!

For Decades, Troodon Was Known as Stenonychosaurus

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In 1932, the American paleontologist Charles H. Sternberg erected the new genus Stenonychosaurus, which he classified as a basal theropod closely related to Coelurus. It was only after the discovery of more complete fossil remains in 1969 that paleontologists "synonymized" Stenonychosaurus with Troodon, and recognized Stenonychosaurus/Troodon's close affinity to the contemporary Asian theropod Saurornithoides. Confused yet?

It's Unclear How Many Species Troodon Comprised

A partial Troodon skull (Wikimedia Commons).

Fossil specimens of Troodon have been discovered across the expanse of North America, in late Cretaceous sediments as far north as Alaska and (depending on how you interpret the evidence) as far south as New Mexico. When paleontologists are faced with such wide distributions, they're usually inclined to speculate that the genus umbrella may be too big--which means that some "Troodon" species may one day wind up being promoted to their own genera.

Many Dinosaurs Are Classified as "Troodontids"

The troodontidae are a large family of North American and Asian theropods that share certain key characteristics (the size of their brains, the arrangement of their teeth, etc.) with the eponymous genus of the breed, Troodon. Some of the better-known troodontids include the evocatively named Borogovia (after a Lewis Carroll poem) and Zanabazar (after a Mongolian spiritual figure), as well as the unusually tiny and delicate Mei, which also stands out for having one of the shortest names in the dinosaur bestiary.

Troodon Had Binocular Vision

Troodon chasing Orodromeus (Coconut Grove Science Museum).

Not only were the eyes of Troodon larger than normal (see slide #4), but they were set toward the front rather than the side of this dinosaur's face--an indication that Troodon possessed advanced binocular vision, with which it could target small, skittering prey. (By contrast, the eyes of many herbivorous animals are set toward the sides of their heads, an adaptation that allows them to detect the presence of approaching carnivores.)

Troodon May Have Enjoyed an Omnivorous Diet

Wikimedia Commons

With its characteristic eyes, brain, and grasping hands, you might think Troodon was built exclusively for a predatory lifestyle. However, the distinct possibility exists that this dinosaur was an opportunistic omnivore, feeding on seeds, nuts and fruits as well as smaller mammals, birds and dinosaurs. One recent study claims that Troodon's teeth were adapted to chewing soft meat, rather than fibrous vegetables, so the jury is still out on this dinosaur's preferred diet.

Troodon Might Eventually Have Evolved a Human Level of Intelligence

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In 1982, the Canadian paleontologist Dale Russell speculated about what might have happened if Troodon had survived the K/T Extinction 65 million years ago. In his "counterfactual" history, Troodon evolved into a large-brained, two-legged, intelligent reptile with big eyes, partially opposable thumbs and three fingers on each hand--and looked and acted like a modern human being. (Some people take this theory a bit too seriously, claiming that human-like "reptoids" walk among us today!)