Freudians will not be convinced

For centuries, the tusk of the narwhal has fascinated and baffled. ... Scientists have long tried to explain why a stocky whale that lives in arctic waters, feeding on cod and other creatures that flourish amid the pack ice, should wield such a long tusk. The theories about how the narwhal uses the tusk have included breaking ice, spearing fish, piercing ships, transmitting sound, shedding excess body heat, poking the seabed for food, wooing females, defending baby narwhals and establishing dominance in social hierarchies. But a team of scientists from Harvard and the National Institute of Standards and Technology has now made a startling discovery: the tusk, it turns out, forms a sensory organ of exceptional size and sensitivity, making the living appendage one of the planet's most remarkable, and one that in some ways outdoes its own mythology. NY Times