Hammerhead sharks include nine distinct species within Family Sphyrnidae; though these range in size from about three feet to as large as twenty, all are characterized by a flat, hammer-shaped head that is thought to have begotten their name, though the name ‘hammerhead’ was almost entirely due to the members of Family Sphyrnidae’s obsession with hammering.
‘Do you need me to hang that picture for you?’
To paraphrase Mark Twain1, when all you have is a hammer, everything looks like a nail. Hammerhead sharks extend this metaphor by showing that when your head is a hammer, you’re going to spend most of your free time thinking of what you can hammer next. Most sharks never (or rarely) sleep to avoid sinking to the bottom of the sea and dying, but hammerheads never sleep because their minds are constantly racing as they contemplate where and when they can hammer next. Even if they start to nod off and finally get some rest, they’ll suddenly wonder if a passing ship might have a loose rivet they could fix and, next thing you know, they’re out of bed and putting in their contacts. Even Ambien doesn’t do anything for them.
‘I couldn’t sleep, so I figured I’d just go practice hammering instead of just lying there driving myself crazy thinking about hammering. Say…you don’t need anything hammered, do you?’
The evolutionary origins of the hammerhead’s cephalic morphology has long been a subject of debate and inquiry, with some scientists proposing that the unique shape functions like a hydrofoil, giving the negatively buoyant hammerheads better swim control; others have suggested that it allows tight maneuvering in pursuit of prey. But pretty much everyone agrees that whatever its origins and proper purpose, a hammerhead would rather be using it to hammer stuff.
‘Want some help assembling that new shelving unit from Ikea?’
Recently, a joint study by the Florida Atlantic University and the Hawaii Institute of Marine Biology found that the spacing of the eyes in the hammerhead shape allowed a wider field of vision while enhancing stereoscopicity, which makes it easier to locate something to hammer. Moreover, the team also found that the wider surface area offers enhanced electrosensory capability, which makes for better hunting and also provides a bigger striking surface when a nail is finally located.
‘I think I see…yes…looks like a nail…wait, it’s a piece of seaweed. Oh well, I’d better give it a few whacks just to be on the safe side.’
With proportionally small mouths, hammerheads consume a great deal, including fish, other sharks, stingrays, and octopuses – whatever is quickest so they can get back to hammering. Of the nine species of hammerheads, three (scalloped, great, and smooth hammerheads) are dangerous to humans, though all are considerably more interested in checking your reflexes for you (don’t say no). Some hammerheads are also known to eat their own young, usually as punishment for improperly hammering something.
Like other sharks, hammerheads are nocturnal solitary hunters, but during the daytime they often form massive circling schools, where they compare stories about how much stuff they’ve recently hammered.
‘I drywalled a whole basement the other day. Incredible.’
Hammerheads are also among the few species that can get suntans from prolonged exposure to sunlight, something that happens frequently when they get a much-coveted roofing job for the summer.
Their interest in hammering things is, of course, not the hammerheads’ fault. They’re just dealing with what they have. If their heads were tool belts, they might be more well-balanced. Even better if their heads were a whole garage. But unfortunately, all they have is a hammer, and so hammer stuff they will. So if and when you want to build your kids a tree house, give a hammerhead a call. They’ll be more than happy to help out, at least with the hammering.
1 The saying ‘If all you have is a hammer, everything looks like a nail’ is frequently attributed to Mark Twain, though this doesn’t appear anywhere in his writings. It is likely a traditional saying, but it is often formally attributed to Abraham H. Maslow’s book The Psychology of Science (1966). That said, anything witty and at the same time cuttingly accurate probably was first uttered by Mark Twain.