Who was the leader of the dinosaurs?

Some dinosaurs are beleived to have lived in herds, probably led by an Alpha leader as most modern herd animal herds are. Some predators may have hunted in packs like wolves and may have had alphas as well. Other dinosaurs wer probably solitary. This is largely speculatory as there is little remaining evidence of dinosaur behaviour ecxept form what we can deduce from their fossil remains.