There’s more to sharks than what you can learn by watching 'Jaws' or 'Open Water'. Sure sharks are fearsome predators, and rest easily at the top of the oceanic food chain, but did you know that these sometimes warm blooded creatures are actually older than dinosaurs? Keep reading to learn more.
1. Sharks come in all shapes, sizes and speeds. There are approximately 370 different known species of sharks. The largest shark is the whale shark, which can grow up to 60 feet long. On the teeny-tiny end, the smallest is the dogfish shark, which measures a mean 8 inches. Think you’re a fast swimmer? Most sharks cruise at an average of 5 mph, but speed up to about 12 mph when they’re hunting down a meal. The fastest shark, the shortfin mako, has been clocked between 20-30 mph.
2. Sharks don’t make the best parents. Sharks reproduce in various ways. Some species lay eggs, while others give birth to either one fully formed pup or an entire litter. But mom and dad don’t stick around for very long. It may sound heartless, but sharks do not care for their young. Shark pups are smaller versions of their parents and are capable of surviving on their own shortly after birth.
3. Who needs dental care...when you can just regrow teeth? Sharks can lose thousands of teeth over the course of their lives. A shark’s teeth are attached to its jaws by loose tendons and can be replaced in as little as 24 hours.
4. Sharks do not sleep. It’s true. Because sharks need to replenish their oxygen supply, they move constantly so that fresh seawater passes over their gills. If they stayed still for too long, they would suffocate. Some speices are able to remain stationary at the bottom of the ocean and push seawater over their gills, but most sharks alternate between periods of rest and activity.
5. The white shark is the most deadly to humans.. According to the International Shark Attack File Worldwide Shark Attack Summary, there were 38 unprovoked shark attacks in U.S. territorial waters (including Hawaii.) in 2005. Florida had the most (18) unprovoked attacks in the United States. Should you be worried? Not really, considering you have a greater chance of being hit by lightning than being attacked by a shark. (Last year, the National Oceanic & Atmospheric Administration reported 43 confirmed deaths due to lightening strikes.) Though some dangerous sharks have been known to attack unprovoked, these attacks are rare. In many cases, a shark will simply mistake a far out swimmer or surfer for a seal.
6. The sixth sense. While humans get by with five measly senses, sharks have a special “sixth sense” called electroreception. All living things, humans included, give off a faint electric field generated by heartbeat and other muscle movements. Sharks have special receptors on their heads which let them sense these fields anywhere from 6 inches to 3 feet away. Basically, it means that you can run, but you can’t hide.
Sources:
"Island of the Sharks". Nova Online. June 2002. Public Broadcasting Service. 31 July 2006. http://www.pbs.org/wgbh/nova/sharks/masters/myths2.html
Handwerk,Brian. Shark Facts: Attack Stats, Record Swims, More. National Geographic. 2005. 31 July 2006.
McCosker, John E. White shark. World Book Online Reference Center. 2006. 31 July 2006.
