Narwhal Sexual Selection (VIDEO)
Caption
Ostentatious animal extremes are often used to compete for and attract mates, a process called sexual selection. Now, thanks to Arizona State University researcher Zackary Graham and his colleagues, we can add the "unicorn of the seas," the narwhal, to the list. They found that male tusks can have over 4-fold variation in tusk length (the same body size males can have tusks ranging from 1.5-feet to 8.2-feet) long. If the highest quality males produce and adorn the largest tusks, then the tusk likely serves as an honest signal of quality to females or males.
Credit
Alex Cabrera, Arizona State University
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