Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

This comic presents a series of academic experts explaining why ancient human groups migrated. An anthropologist explains a group moved north, driven by intertribal violence. An oceanologist says a mass migration was prompted by rapidly rising sea levels. A biologist explains another group moved because they had wiped out every tasty animal larger than a goat. Then the final panel shows "Person who has never left own couch" declaring "Humans are natural-born explorers!" The joke satirizes the romanticized notion that humans explore out of innate curiosity or wanderlust, when in reality historical migrations were typically driven by war, environmental catastrophe, and resource depletion -- decidedly un-romantic motivations. The couch-bound person represents armchair philosophers who idealize human nature without understanding the grim realities behind it.