The Layers of Narwhal's Tusk Tell The History of Its Life in a Rapidly Changing World 14 MARCH 2021 From the outside, the narwhal's unicorn-like tusk is a striking curiosity. On the inside, this long protruding tooth contains an entire life history of the marine mammal's migration and meals, from its first breath to its last.
Peeling back each of these growth layers, researchers have now read the rings of 10 narwhal tusks from northwest Greenland. "It is unique that a single animal in this way can contribute with a 50-year long-term series of data," says marine mammal researcher Rune Dietz from Aarhus University, Denmark.