Narwhals' tusk is a sensory tooth, not a horn

The narwhal's iconic "horn" is actually an elongated left canine tooth, primarily found in males, growing up to 10 feet long in a counterclockwise spiral. This remarkable tooth isn't just for show; it's a sophisticated sensory organ. Millions of nerve endings within the tusk allow narwhals to detect subtle changes in water temperature, salinity, and even the presence of prey. This built-in environmental probe helps these elusive whales navigate their icy Arctic home, revealing a unique adaptation for survival in harsh polar conditions.