Size and Weight:
The slim, fast, two-legged Othnielia was named after the famous paleontologist Othniel C. Marsh--not by Marsh himself (who lived in the 19th century), but by a tribute-paying paleontologist in 1977. (Oddly, Othnielia is very similar to Drinker, another small, Jurassic plant-eater named after Marsh's arch-nemesis Edward Drinker Cope.) In many ways, Othnielia was a typical ornithopod of the late Jurassic period. This dinosaur may have lived in herds, and it certainly figured on the dinner menu of the larger, carnivorous theropods of its day--which goes a long way toward explaining its presumed speed and agility.