Shark Week on Discovery Channel is winding down, and as the final credits roll for this year’s toothy line-up (including predictable titles like “10 Deadliest Sharks,” “Killer Sharks,” and “When Fish Attack 3”), it’s an excellent moment to reflect on the other reasons to be fascinated by sharks. Sure, many sharks have are impressive hunters with serious teeth, but there are so many other reasons they deserve a dedicated week of programming. Here are just a few of them:
1) No Bones! Sharks, and their evolutionary cousins skates and rays, are in the class of animals that scientists call chondricthyes or “cartilaginous fish.” They don’t have true bones like mammals, birds, or most other fish. Instead their skeletons are made of cartilage—the same flexible material in human ears.
2) Smelling in Stereo – Marine researchers have long known that sharks have a strong sense of smell and are highly skilled at following their noses straight to injured prey. Until recently, scientists believed that sharks used differences in the concentration of blood in the water to determine which direction to swim in search of food. But it turns out that sharks actually chart a course toward lunch by noticing when a smell reaches one nostril before the other. The difference in timing—akin to humans using our stereo hearing to tell where a distant voice is coming from—reliably tells the shark which direction to head.
3) Sixth Sense – Call them the superheroes of the sea: sharks literally have a sixth sense known as electroreception. All living things produce a small amount of electric current (known as bioelectromagnetism) as our cells, nerves, and muscles go about their regular functions, and sharks can sense these weak electromagnetic fields using special receptor cells on their heads. This superpower is especially handy when prey hides or burrows in the sand.
4) An Impressive Lineage – Sharks were swimming in our ancient seas more than 400 million years ago—long before the age of dinosaurs. If you think the great whites that so often steel the Shark Week spotlight are impressive, you should get to know their (now extinct) ancestor the Giant Megatooth shark, which may have weighed as much as 50 tons.
5) Super Skin – The skin of a shark is one of nature’s simple, elegant designs. While it may look smooth, shark skin is actually made up of tiny, ribbed plates called dermal denticles. These overlapping layers of scales create a surface that is difficult for parasites and microorganisms to attach to and extremely hydro-dynamic. In fact, scientists and designers are mimicking shark skin for applications ranging from faster Olympic swimming suits to medical devices that repel pathogens.
About the Author
Christine Hoekenga is a freelance writer, editor, and content strategist, specializing in science, natural history, and sustainability. Her love for the ocean dates back to childhood when she was knocked face-down by her first wave on the California coast. Since then, Christine has been immersed in marine issues as a student, a SCUBA diver, a science writer, and an organizer and advocate for environmental nonprofits. Her interests include coral reefs, octopods, marine fisheries, and all types of citizen science projects.