Narwhal's tusk tells on its feeding habits, and more
Using mercury and stable isotopes of carbon and nitrogen to obtain such information, the team were able to also analyse how the ice cover and the impact of potential toxic compounds have evolved over time.
Their findings were published in the Current Biology journal.
The tusks of the ten narwhals involved in the research were 150 to 248 cm long, and contained data from the time period 1962 to 2010.