For convenience, groups of animals are given specific names; for example, a group of dogs is called a "pack;" a group of lions is called a "pride" (get the picture?)
in the wild, a group of baboons is called, a "congress"
Marriage originated as a religious and/or private institution. Governments took it over when the prince figured out he could TAX it. It first started in primitive times just as mating. Then as humans...