Species

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Species

• There are over 360 species of sharks!
• They can range in size from small enough to fit
  in your hand to up to 46 feet!!
• Smallest Shark is the Pygmy Shark
• Largest Shark is the Whale Shark
• Filter feeder, feeds on plankton

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Whale Shark
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Skeleton

• Sharks are cartilaginous fish
• Skeleton made of cartilage which is lighter and
  more flexible than bones

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Respiration

• Sharks have uncovered gills used for respiration
• Extract oxygen as water passes over the gills

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• Most species of shark can pump water over their
  gills for when they are not moving using the
  spiracle
• A small percentage of sharks need to stay in
  constant motion to respire

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Teeth

• Sharks teeth are NOT attached to their jaws
• Teeth range from needlelike to large flat teeth

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• Teeth are grown and replaced often
• Sharks have multiple rows of teeth
• Sharks can have about 25,000 to 30,000 teeth in
  one lifetime
• Some replace teeth every
• 8-10 days, others every few
• months

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Life Span

• Lifespan varies by species
• Most live about 20 30 years
• The spiny dogfish can live up to 100 years
• It is thought that the whale shark can live over
  100 years as well

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Sense of Smell

• Incredible sense of smell
• They can detect amounts of blood as small as 1
  ppm. (part per million)
• Rely on sense of smell to locate prey

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Locating Prey

• Electro-receptors
• Allow sharks to sense minute electricity caused
  by muscles and nerves in prey

Lateral lines Sense organ used to detect motion
or vibrations in the water
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Vision

• Sharks have eyelids but do not blink
• Water surrounding eye cleans it
• Sharks have a membrane over eye that protects
  when being attacked or during predation
• Great White Sharks roll eyes back when attacking

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Do Sharks Sleep??

• Scientists unsure!!
• Possible they sleep in a similar manner to
  Dolphins
• Half the brain sleeps at a time

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Why Attack?
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Shark Attacks

• 2000 - 79 attacks, 11 fatalities
• 2005 - 61 attacks, 4 fatalities
• 2006 - 62 attacks, 4 fatalities
• Majority occur in the United States
• More people die from lightning strikes each year

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Sharks Involved

• Three types of sharks have been involved in a
  significant amount of attacks
• Great White
• Tiger Shark
• Bull Shark

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Great White Shark

• Great Whites are generally about 13-16 ft and
  weigh 1500 - 2450 lbs
• Found in waters between 54 and 75 degrees F

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• Countershading
• White underside and gray dorsal side
• Difficult to see when looking at horizontally
• When seen from above, gray blends in with the
  water
• When seen from below, white blends in with
  surface of water

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Typical Prey

• Sting rays, tuna, smaller sharks, dolphins,
  seals, sea lions
• Shark attacks most often occur in the morning,
  within 2 hours after sunrise
• Hard to see a shark close to the bottom
• Attack from below at fast speeds

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Tiger Sharks

• Average 11 feet and 850 - 2000 lbs
• Commonly found around islands in the central
  Pacific
• Dark spots and stripes are prominent in young
  sharks and fade as the shark matures

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Hunting Habits

• Teeth can bite through bone and turtle shells
• Known to circle its prey and even study it by
  prodding it with its snout
• Tiger sharks devour their entire prey when
  attacking

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Hawaii

• Tiger sharks have become a problem in Hawaii
• Hunted to help control attacks, but no decrease
  occurred
• Considered sacred by native Hawaiians

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Bull Shark

• Dwell in shallow water, possibly posing highest
  threat to humans
• Can tolerate freshwater
• Males 6.8 ft, about 200 lbs
• Females 11.5 ft, about 700 lbs

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Hunting Habits

• Bump and Bite Technique
• Shark circles prey often bumping them before the
  actual attack.
• They are extremely territorial and will attack
  other animals that enter their territory.

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Why attack?

• Mistaken Identity
• Shark mistakes a person in the water as a seal
  when looking from below the waters surface
• Curiosity

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• Sharks typically bite once and then swim away
• Explanations
• Humans do not taste like their typical prey
• Return to the prey after it exhausts itself

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Dolphin Protection

• Sharks will not attack when dolphins are around
• Scientists unsure why this phenomenon occurs

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Avoiding an Attack

• Avoid water during darkness or twilight hours
• Do not enter water if bleeding from an open wound
• Do not wear shiny jewelry resembles fish scales
• Avoid areas near commercial fishing
• Avoid murky waters
• Do not splash a lot

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Fending off an attack

• Hit back in sensitive areas such as the eyes and
  gills
• Shows shark you are not defenseless

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Hammerhead Shark

• Habitat Shallow tropical and warm temperature
  waters
• Diet Stingrays, Other small sharks, fish,
  crustaceans
• Size 12 - 20 ft.
• Attacks 18 (0 fatal)

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• Hammerheads have small mouths and seem to do a
  lot of bottom-hunting. (Stingrays!)
• Their wide-set eyes give them a better visual
  range than most other sharks.

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• They are also known to form schools during the
  day, sometimes in groups of over 100.