Top Facts about Sharks
- The more you learn about sharks, the more you will come to understand the overall value of these forms of aquatic life. Too much of what we know about them comes from movies – and while that can offer a thrill – it usually isn’t based on what they are really all about.
- There are over 400 known species of sharks today that have been identified by experts.
- It is believed that sharks have been around for more than 420 million years!
- Sharks have either 5 or 7 gills that are slits on the side of the head.
- Some species of sharks do live in freshwater but the majority of them live in saltwater in depths up to 6,600 feet.
- Sharks have very sharp teeth, and they will be replaced for their entire life. As a tooth falls out, another moves into place. Some species can have up to 30,000 teeth in their lifetime.
- Many of the larger species of sharks are filter feeders and they consume only small aquatic life such as plankton.
- One of the methods used by experts to properly handle sharks is to stroke them gently on the nose. This can cause them to temporarily enter a natural state of immobility that isn’t harmful to them.
- Sharks have very good senses including their vision and smell. They also are able to pick up on vibrations of movements of other living things in the water.
- The Spiny Dogfish Shark has the longest lifespan of all species – around 100 years.
- Sharks can be very social or loners. Typically, the larger the species is the more likely they are to live a solitary lifestyle.
- Sharks do sleep, but many still believe that they don’t. The design of their body allows them to sleep with their eyes open and they can continue to swim while sleeping. They often sleep for very small intervals at a time. It is believed that only one half of their brain sleeps at a time.
- Investigations regarding shark attacks indicate that almost all of them are the result of provoked efforts on the part of humans rather than the sharks being aggressive predators. Only a handful of species are believed to ever take part in aggressiveness towards humans without being provoked.
- Steven Spielberg, the director of Jaws, has been involved in many efforts to try to reduce the negative images about sharks that his movies created. He has stated that he regrets making the films due to the stigma it has created for sharks even several decades later.
- Even with many of the captivity locations doing all they can to replicate a natural environment, most species of sharks don’t do well there. They are prone to diseases, high levels of stress, and aggressive behaviors that they normally don’t exhibit in the wild.
- Sharks are easily susceptible to various forms of cancer and parasites.
- Sharks often move around at a leisurely pace called cruising which is about 5 mile per hour. Sharks can move fast though, up to 12 miles per hour, when they feel threatened. The fastest is the Shortfin Mako Shark which can move up to 31 miles per hour.
- Sharks take a long time to digest their food due to the J shape of the stomach and the fact that they have shorter intestines than other mammals. Some sharks are carnivores and others are filter feeders.
- Sharks don’t mature until much later than other types of fish. It can be 10 years or longer for most species before they will mate. As a result, conservation efforts to increase numbers can be very difficult.
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