The narwhal (Monodon monoceros)'s a medium-sized toothed whale that lives year-round in the Arctic. One of two species of whale in the Monodontidae family, along with the Beluga whale, the narwhal males are distinguished by a characteristic long, straight, helical tusk extending from their upper left jaw. Found primarily in Canadian Arctic and Greenlandic waters rarely south of 65°N latitude, the narwhal's a uniquely specialized Arctic predator. In the winter, it feeds on benthic prey, mos… (More on Narwhal)