Narwhal Tusks

Since they are so solitary and live in a remote, poorly understood environment, narwhals are also referred to as the unicorns of the sea. It is a species of whale that can only be found in the waters of the Arctic and can be identified by its long, pointed tusk, which may reach lengths of up to 9 feet.

While there are still many unknowns regarding the species, its tusk has long been considered to be both its most intriguing and mysterious characteristic. Scientists have never been able to determine what it is employed for, or what evolutionary factors caused male narwhals to develop what is essentially an enlarged tooth. Some hypotheses contend that it's a survival mechanism that enables them to hunt more successfully, but since female narwhals are known to outlive males, this explanation doesn't appear to fit.