What is property, and why does our species happen to have it? The Property Species explores how Homo sapiens acquires, perceives, and knows the custom of property, and why it might be relevant for understanding how property works in the twenty-first century. Arguing from some hard-to-dispute facts that neither the natural sciences nor the humanities—nor the social sciences squarely in the middle—are synthesizing a full account of property, this book offers a cross-disciplinary compromise that is sure to be controversial: All human beings and only human beings have property in things, and at its core, property rests on custom, not rights. Such an alternative to conventional thinking contends that the origins of property lie not in food, mates, territory, or land, but in the very human act of creating, with symbolic thought, something new that did not previously exist. Integrating cognitive linguistics with the philosophy of property and a fresh look at property disputes in the common law, this book makes the case that symbolic-thinking humans locate the meaning of property within a thing. The provocative implications are that property—not property rights—is an inherent fundamental principle of economics, and that legal realists and the bundle-of-sticks metaphor are wrong about the facts regarding property. Written by an economist who marvels at the natural history of humankind, the book is essential reading for experts and any reader who has wondered why people claim things as “Mine!,” and what that means for our humanity.