In the series, cavemen were never really fully supplanted by modern humans, but integrated into "Homo sapiens" civilization as a separate species sub-group. Cavemen are a small but widespread minority group that have been present in every global civilization since the dawn of recorded history (a montage scene in the opening credits shows Cavemen in Egyptian hieroglyphs, when George Washington crossed the Delaware River, standing with Abraham Lincoln, participating in the space program, etc.). Effectively, Cavemen form another ethnic minority in the modern world, which faces several prejudices from "Homo sapiens" (sometimes referring to humans by the derogatory term "Smoothies" in reference to their relative lack of hair, or "Sapes" in reference to their species). Although these cavemen self-identify as Cro-Magnon, their facial appearance and physical anatomy is reminiscent of the Neanderthal.