Hammerhead shark
Hammerhead sharks tend to school during the day and hunt prey at night. As members of Chondrichthyes, their skeletons are composed of cartilage.
Source
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"OpenStax College, Fishes. October 17, 2013."
http://cnx.org/content/m44687/latest/Figure_29_02_04.jpg
OpenStax CNX
CC BY 3.0.
