Age is an important parameter to understand species life‐history characteristics. Recently, DNA methylation methods have emerged as innovative tools to estimate the age of marine mammals. Narwhal ( Monodon monoceros ) epigenetic age estimates were computed using beluga ( Delphinapterus leucas ), killer whale ( Orcinus orca ), bowhead ( Balaena mysticetus ), odontocete, cetacean, and mammalian epigenetic clocks and were compare...