Sharks, Friend or Foe?
Duh-dum, duh-dum, duh-dum, …Shark Week! Well friends, it is that time of year again. Sharks take center stage this week on cable television. With all the hype, it can be hard to separate the fact from the fiction. Are sharks friends or foe? Perhaps they are not either. Perhaps we should look at them as oft-misunderstood, ecologically-important predatory ocean fish. So what are sharks?
Sharks ARE ancient. Sharks are sometimes referred to as “living fossils”. Ancient sharks lived in the oceans long before animals colonized the land. Sharks have lived on earth for at least 400 million years! Most fossil evidence of early sharks exists as fossil teeth along with a few skin impressions. Ancestry of sharks dates back before the earliest known dinosaur. Although the dinosaurs are long gone, sharks still live on.
Sharks ARE diverse. Currently there are approximately 400 described species of sharks, however new species are being described all the time. In addition, there are around 400 species of rays, a close relative of sharks. The largest shark, the whale shark, grows to 60 feet long and eats plankton! On the other hand, the cookie cutter shark grows less than 2 feet long and is a ravenous carnivore, luring in prey with its glowing photophores before it attaches to the larger fish with sucking lips, pointy teeth, and bites a plug out of the fish!
Sharks ARE fascinating. Researchers are learning more about sharks all the time! Some of the most fascinating facts are listed below.
- Sharks can sense electrical impulses of another animal’s heartbeat or muscle movement.
- Sharks have rows of teeth arranged in layers so if any break off, new sharp teeth can immediately take their place, like a conveyer belt. Sharks can shed thousands of teeth during their lifetime.
- Of all the 400+ species of sharks, only about 10 species pose a potential threat to humans.
Sharks NEED our respect and protection. Sharks have reproductive strategies more similar to mammals than many fish. Most sharks do not reach reproductively maturity until they are 10 years or older and generally have less than a dozen offspring at a time. As such, sharks are very vulnerable to overfishing, and it would take a population many years to recover. As apex predators, many sharks species are also very important do complex marine food webs. Sharks are involved in several steps of this web including, feeding on the sick and dying, and feeding on larger animals such as whales, seals and tuna, which have few predators. The United States is part of global action to help decrease harmful fishing practices of sharks, including shark finning. You can help protect sharks by making informed consumer choices.
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