Lesothosaurus was a small, early, lightly-built dinosaur. It was an herbivore (plant-eater) and a fast, agile runner. It was small and lizard-like, about 3 feet (1 m) long. It walked on two long legs, had four-toed feet, five-fingered hands, short arms, a long pointed tail, a flexible neck, and a small head. Its head was short and flat with large eyes. It had sharp, pointed front teeth and arrow-like cheek teeth, but its lower jaw ended in toothless bone. 