The explanation on how and why in Revenge of Makuta Wimeru Dino-AU GT and Stephen can still be conciderred siblings.

Gotaru finds two abandoned eggs, one in the jungle, one in the desert, and desides to take care of them. The surprise is huge, when the eggs, he had completely thought would be herbis, hatch to be carnis instead. Despite the little ankle-biters growing one day to be dangerous, Gotaru can't bring himself to abandon the little ones, and raises them to adulthood.