By Christine Hoekenga. posted www.speakupfortheblue.com
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.