Japan tried several times to be an imperial nation. It started when they tried to invade Korea. They failed, but they turned their failure into motivation. During the Meiji Restoration, Japan decided to become a modern Empire. The decision to become an empire comes with an effort to look for a target market. They became an imperialist nation by conquering Korea again and Taiwan. By becoming an imperialist nation, Japan gained power, prestige, wealth and security.
I would say we have better technology, so they can take part of the DNA and see when they were around. How long it's been since a dinosaur in the Triassic Era walked the earth.