I received this Official Postcrossing card from Wisconsin! This illustration, simply titled “Hammerheads”, features exactly that – hammerhead sharks! Hammerhead sharks have been a subject of my intrigue back as a kid. They’re most easily identified by their strange, elongated and flattened heads, which resemble a hammer. This structure has its own name – it’s known as a cephalofoil. On each end of the cephalofoil is an eye, which gives them a widely spread visual field. There are multiple theories on how the hammerhead shark evolved to have its cephalofoil, but the most prominent one comes from its optimization of ampullae of Lorenzini. I mean, certainly EVERYONE’S heard of the cephalofoil’s ampullae of Lorenzini, right? XD Let’s break it down – “ampullae of Lorenzini” are just electrical sensors in the heads of shark and certain other fish. These sensors can pick up on movements from other sea creatures (read as “prey”). For the hammerhead shark, these sensors are spread out over a larger surface area because of their long head. It’s kinda like a metal detector! Hammerhead sharks particularly love to eat stingrays, so this capability allows them to find them despite how well-camouflaged they might be. I guess you could call that “x-RAY vision”… no? I guess my ampullae of Lorenzini for good jokes don’t seem to be functioning… anyway, thank you lots for sending me this cool postcard!