The narwhal’s tusk reveals its past living conditions – Science Daily

Every year, a new growth layer is added to the narwhal’s spiralled tusk. The individual layers act as an archive of data that reveals what and where the animal has eaten, providing a glimpse of how the ice and environmental conditions have changed over its long life span (up to 50 years).Same as rings in a tree trunk, every year a new growth layer is added to the narwhal’s tusk, which grows longer and thicker throughout the animals life. Because the tusk is connected to the rest of body through…

Click here to view the original article.