Final answer:
The narwhal is a marine mammal that has a hammer-shaped head and a single tusk. Its body coloration is similar to a killer whale, but it is larger in size.
Step-by-step explanation:
The narwhal is a marine mammal that belongs to the family Monodontidae. It is known for its distinct features, including a head that is shaped like a hammer and a single long tusk that originates from the head. The narwhal's body coloration is dark, resembling that of a killer whale, but it is larger in size than a killer whale. Additionally, the narwhal has tail fins that extend horizontally from its body.
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