Artwork showing the relative scale of humans and Kentrosaurus ('pointed lizard'). This animal, from Tanzania, lived around 152 million years ago during the Late Jurassic period. It measured 5.5 m (18 ft) long and was herbivorous. Kentrosaurus belonged to a group of dinosaurs named after their prototype, the stegosaurids, armed with tail spikes or 'thagomizers' to protect themselves and deter predators.