16. Narwhal (Monodon monoceros)
The narwhal is a medium-sized Arctic whale with a sleek mottled gray body and, in males, a long, spiraled ivory tusk that can grow up to 10 feet—actually an enlarged tooth emerging from the left side of its head.
That unicorn-like tusk fascinates readers who thought such features only existed in myths. The tusk is packed with millions of nerve endings and helps the narwhal sense changes in water salinity, temperature, and pressure. Males sometimes “fence” with their tusks during mating season. Living in icy waters where few humans venture, these “unicorns of the sea” remind adults that the planet still holds majestic, almost magical creatures we rarely get to see.
