In more traditional societies, the family is the primary social structure (and support structure). It's only in "modern" society that we let go of that idea an

In more traditional societies, the family is the primary social structure (and support structure). It's only in "modern" society that we let go of that idea and handed the responsibility over to government. And when said government fails, family is the first thing people fall back on. So I wouldn't be too sure that humans are biologically solitary animals.