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In page Hammerhead shark:

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Hammerheads have disproportionately small mouths compared to other shark species.[6] Some species are also known to form schools.[7] In the evening, like most other sharks, they become solitary hunters.[citation needed] National Geographic explained that hammerheads can be found in warm, tropical waters, but during the summer, they begin a mass migration period in search of colder waters.[8]