The evolution of the Narwhal occured in 66 million years.

Mesonychids - 66 Million years ago

Jan 1, 1000

Paleocene period - Mesonychids were wolf-like animals, with 4 hooves/paws, used to walk on land.

Pakicetus - 56 Million years ago

Jan 1, 1300

Eocene period - The Pakicetus was a four-legged, land mammal, resembling the crocodile. The Pakicetus had a thickened skull bone, known as the auditory bella, which is used for underwater hearing.

Ambulocetus - 50 Million Years ago

Jan 1, 1350

Early Eocene Period - The Ambulocetus was an amphibian, crocodile-like animal. This animal had four legs, which were better suited for swimming rather than walking. This animal also had an inner ear bone, which enabled it to hear underwater.

Dalanistes - 48.6 Million years ago

Jan 1, 1400

Late Early Eocene Period - The Dalanistes was also a four-legged, with long narrow skulls, and an openings at the end of the skull.

Rodhocetus - 48.6 Million years ago

Jan 1, 1450

Lutetian Period - The Rodhocetus was an early whale that had four, short legs, with webbed hands and feet.

Narwhal - Present day

Jan 1, 2016

Narwhals are medium-sized, slim whales that live in the Arctic Circle. Their distinguishing trait is the horn/tusk that comes from the upper lip of male Narwhals. The Narwhals do not have any pelvis-like structures to show they did, at one point have four legs.