The crocodiles are one of the oldest living creatures. They have survived the change in the world since the time of the dinosaurs. The oldest hippo dates back to 33.9 million years ago. Whereas the oldest crocodile dates back to 205 to 223 million years ago. So the crocodiles are definitely older than hippos. Crocs are one of the most successful species of all time. They even managed to outlive the dinosaurs.