The Mystery of the Hammerhead Shark
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Types of Sharks
The coastal lifestyle and appearance of hammerhead sharks (Sphyrnidae) have long made them an ocean animal of mystery to their human observers.
Why did they evolve to have long, flat heads?
Without any data to back it up, the casual observer might easily hypothesize that the long, flat heads provide them with better eyesight.
Recent research published in the Journal of Experimental Biology 212, 4010-4018, confirms what many casual observers suspected.
Not only do the wide set eyes of hammerhead sharks provide them with better forward looking depth perception of ocean objects, but also the eyes set on the sides of their heads provide them with better backward looking ability.
One hammerhead species, the scalloped hammerhead, was measured as having a full 360o visual field.
The research results appear to mesh with another line of inquiry into the shape of the hammerhead shark's head. According to research presented in the Journal Copeia Vol. 1995, No. 2, the head of the hammerhead shark also evolved to help it with improved mobility.
The author states, "The present results, together with observation of their swimming behavior, strongly suggest that the hammerhead sharks utilize their head for hydrodynamic purposes in various ways."
Taken together the research suggests that the mystery of the hammerhead shark can be explained as an evolutionary process that provided them with the dual ability to more effectively see potential food sources and more effectively maneuver their bodies to catch the prey once sighted.
More Hammerhead Shark Information: Currently eight species of hammerhead sharks have been identified, divided into two genera, Eusphyra and Sphyrna. Only one species, the Winghead shark (Eusphyra blochii) in the Eusphyra genus.
© 2009. Patricia A. Michaels