The term 'Marine Mammal with Tusks' can be summarized as the WALRUS, which is a 6 letter word. The WALRUS is a large marine mammal that lives in the Arctic Ocean and adjacent seas. It is easily recognizable by its long tusks, whiskers, and distinctive moustache. Walruses are known to use their tusks for activities such as digging, fighting, and hauling themselves onto ice floes. They feed mainly on shellfish and other invertebrates.