The Narwhal's Double Twist: A Tale of Evolutionary Excess? The narwhal's tusk has long fascinated humans, from medieval Europe to modern day souvenir hunters.
Beneath its mystique lies a complex tale of evolutionary adaptation, with new research revealing that these spiraling structures are not as singular as previously thought.
According to a study published in Nature Communications, narwhal tusks contain two internal spirals: one oriented leftward and the other twisting in the opposite direction.