The Troodon formosus was a small dinosaur, one that was considered a coelurosaurian, which is to say that it was a member of the same group of evolutionary animals that today’s birds belong to.
Scientists have found fossilized remains that show them nesting parents and egg clutches and small infants in nests, so they were apparently ground nesters, but at the same time, they had some of the same reproductive tendencies that crocodiles had, as well as birds.
Finding the fossils sheds a lot of light on how they reproduced and how they lived.
Science believes that the Troodon had a pair of eggs, usually no more than two, periodically and then incubated them much as birds do, in nests on the ground, warming them by body heat, sitting on them as modern birds do.
This suggested to the scientists that these kinds of dinosaurs were an important link in evolution, and that they bridged the gap between dinosaurs and birds of modern times.
The Troodon had a larger brain for its size than most dinosaurs and was probably among the smartest dinosaurs alive at that time. Its brain was much larger than those found in living reptiles today and so it was probably smarter than modern day birds.
It walked or ran on two legs, and was a carnivore, eating small lizards, mammals and invertebrates from the water.
It had rotatable forearms, was probably able to grasp things to eat them, with hands of a sort that had three fingers and most likely helped them a lot when hunting.
It also had very large forward facing eyes that gave it remarkably keen vision to help it in its hunting, with the means to see very well even at night.
Troodon would have been a formidable hunter and stalker for that time period and was well able to take care of itself and its eggs, probably hunting in packs.