The Nanosaurus (pronounced NAN-uh-SAWR-us) was one of the smaller dinosaurs to ever exist, standing just under two feet tall and four feet long. If these dinosaurs were around today, they would be about the size of an average dog, except the fact the were pretty much a giant lizard walking on their hind legs. Discovered by Othniel Charles Marsh in the 1877, not much information is known about them but they are very similar to what is now called the Othnielosaurus or Othnielia. Most people think of them as "The Tiny Dinosaur" because that is what they are referred to in most popular books. Believed to be a herbivore and also bipedal, they survived mostly on plants and shrubs and possibly bugs and small animals as well. Most of the fossils have been found in the Colorado area and parts of Wyoming which is not a huge area, where they actually all inhabited is unknown but it seems mostly around the western central North America . It is believed that the Nanosaurus lived 155 to 148 million years ago during the late Jurassic period.