Sunday, January 1, 2012

Planet Shark

I love taking my kids place and for New Years we went to the Science Place to check out the new Plant Shark exhibit. It was fantastic. Our tour guide was Patrick and he was incredibly knowledgeable about sharks! Not so much about how old our planet really is, since he believes it is 380 million years old! Guess he must not buy into the whole God created the heavens and the Earth and our planet is not that old, but was not there to bicker about theology.

So the first thing we learned is that the way we pronounce the word "shark" is all wrong. It actually is a New Zealand/Holland lineage and the word is pronounced "Shack", (ʃɑːk) think basketball player Shaquille O Neel.

Types of Sharks: 
There are over 350 different types of sharks such as the Tiger (think Soul Surfer movie), Whale, Blue, Bull, Goblin, Great White, get the point. There are tons of great little web site for kids to learn more about the different types of sharks and what they look like: So I won't list them all!

The kids learned all about how sharks bodies are made up of cartilage except for their teeth and spines. So sharks do not fossilize and the only way they can determine the size of a shark is buy the teeth and spines left behind. A sharks size is determined by its jaw size more than anything else. Interesting little fact about sharks teeth we learned is that sharks loose there teeth every 2 weeks and a new set grows in. This happens throughout their entire life time. Most people when they think of sharks they think sharp teeth...but this is not always the case. It really depends on what type of shark you have and what they eat. Some sharks have nothing but molars for teeth. Also, the color of the sharks teeth is not determined by the type of shark it is, but the region in which it inhabits. The color is from the minerals that are local to that region. So a sharks habitat that is mainly limestone would have different color teeth from a place were its mainly jasper, talc or rhodonite. Plus, some sharks move their teeth up and down and some move them like saw blades back and forth. The Tiger shark for instance is the type of shark that attacked the girl from soul surfer movie and he uses a back and forth movement.

The largest threat to sharks is from the "Shark Fin  Soup Threat"  Asia has such a fascination with sharks that their fins are considered a delicacy. This one movement alone has put sharks on the endangered species list,also known as the ETL or extinction level event

 Shark Sensory:

Sharks have this wonderful thing called Electroreception this is were sharks pick up on electricity from prey within a 3ft range from their nose! This is an awesome little sense and also cost the government billions of dollars back when submarines were being tested. The government thought that the Russians had invested a new weapon because the submarines they docked had these circular holes all over them.  It took a team of scientist to figure out it  was the cookiecutter shark was taking bites out of submarines. Apparently since the outside of subs use to be styrofoam and the shark picked it its electricity it thought it was food and kept taking bites out of it. Pretty funny actually.

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 Shark Dissection:

I love hands on experiments and nothing beats getting to open up a dogfish shark and takes its guts out to peer inside. That's exactly what we got to do with a dogfish shark! Oh yea, it was as cool as it sounds. I attached the link to several different sites that allow you to watch or give you instruction on how to dissect a dogfish.

video of dissection

 Great Questions to ask: 
  • How has the shark adapted to its environment?
  • Where is the shark found? What does it eat? How does it swim? What is its prey? What preys on it? How does it reproduce?
  • What is the external and internal anatomy of a shark?
  • How are sharks similar to and different from bony fish?
  • Why are Spiny Dogfish caught by humans? What are some of the impacts of over fishing?
  • How big was the fossil shark Megalodon, based on the size of its teeth?

Shark attackAttacks by sharks are extremely rare and should be put in context. The dangers that we confront each and every day of our lives from driving to work, to playing sport are far greater.
There are many theories and ideas about why Great White sharks attack humans and whether it is deliberate or a case of mistaken identity. Today scientists and researchers remain divided. What we do know is that humans have not featured in the diet of Great whites until relatively recently when we began to enter the water. We also know that we give off similar signals to prey types that Great Whites target such as whales, dolphins and seals. It is therefore reasonable to assume that they attack humans because they recognize us as food.

10 ways to avoid attack
Avoid entering the water at night and particularly at dawn and dusk.
Many of the more dangerous sharks are actively feeding at these times. They can see and sense you long before you can see them. 
Always swim in a group.
Sharks usually attack lone individuals.
 Avoid entering the water if you are bleeding.
Sharks have an acute sense of smell and can quickly find the source of even minute amounts of blood in the water.
Avoid entering the water where people are fishing or have been fishing recently.
Or where other animals are hunting for fish. Diving sea birds are a good indicator that other animals may be fishing in the area.
Avoid entering the water if sharks are present.
Also leave immediately if sharks are seen. Move swiftly but calmly as sharks are attracted to splashing. It the shark is already swimming at you move as fast as you can to safety.
 Avoid splashing a lot or swimming with pets.
Erratic movements and the quick movements of animals like dogs can attract sharks.
Avoid wearing shiny jewelery while swimming.
  Jewelery can reflect the light and look like fish scales or a small school of fish in the water.
Be vigilant around the edges of sandbars or steep drop-offs.
These are frequently visited by sharks.
Don't think that you are safe because dolphins are present - this is a myth.
Sharks are often found in the presence of whales and dolphins as they eat the same foods.
If attacked by a shark do whatever it takes to get away. Be aggressive rather than passive.
Yell and scream to attract rescuers and fight the shark off by attacking its most vulnerable areas - its gills and eyes.

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