Taxonomy
 Kingdom – Animalia
 Phylum – Chordata
 Class – Chondrichthyes (sharks, skates, rays,
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sawfishes)
Order – 8 orders (Lamniformes (mackerel sharks))
Family – 30 families (Lamnidae)
Genus – 50+ genuses (Charcharodon)
Species – 370-400+ species (carcharias)
 List of species
External Anatomy
Internal Anatomy
Feeding
 Most are carnivorous but some are filter feeders (whale
sharks, basking sharks)
 Tiger sharks are referred to as the “garbage guts” of the
shark world
 Contrary to popular belief, most sharks are picky about
what they eat
 Great whites choose only animals with blubber
Respiration
 Most sharks have to keep
moving to move water
over their gills
 Water enters the gill
chambers through the
mouth or spiracles and
exits through the gill slits.
 Blood in the gill filaments
absorbs oxygen from the
incoming water.
Circulation
 2-chambered heart
 Blood flows from heart to
gills to body tissues back
to heart
 Countercurrent heat
exchange enables fastmoving sharks to be from
10 to 20 degrees warmer
than the water around
them
Senses
 Hearing – have inner ear, attracted to low frequency
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sounds, can hear up to 0.6 miles
Vision – excellent, 10x more light sensitive than us,
attracted to shiny and thrashing, can see 50 to 100 ft.
Taste – have taste buds, actually spit things out
Smell – excellent, function in only smell not breathing, can
detect some chemicals as small as 1 part per billion
Feel – group of sensory cells along outside of body called
the lateral line used to detect vibrations in the water
Electroreception – Ampullae of Lorenzini detect
electric fields given off by living creatures
Reproduction
 Mating is rarely witnessed, male bites onto dorsal fin
and internally fertilizes with clasper while over top of
the female
 Can be oviparous (horn, swell sharks),
ovoviviparous (mako and sand tiger sharks), or
viviparous (hammerhead sharks)
 Gestation period is very long from 9 months up to 3 ½
years
Shark Attacks
 You are more likely to be killed by stepping in a sand hole
and having it collapse than you are by a shark
 Tips to avoid attacks:
 Don’t swim during low light periods
 Stay in groups
 Be knowledgeable about the area you swim/dive/surf in
 If you find one, leave it alone
 Avoid looking like prey
 Sharks are attracted to:
 Blood, splashing and loud noises, shiny colors
 International Shark Attack File
Ecology and Human Uses
 Pilot fish, remora, and others clean parasites like copepods
and flatworms off sharks
 Integral part of the food chain:
 fishes, crustaceans, mollusks, marine mammals, and other
sharks
 Sharks, elephant seals, and killer whales have been known to
eat sharks
 Behavior researched mainly for avoiding attacks
 100 million sharks are killed every year by humans even
though several species are endangered and illegal to kill
 Humans use sharks for:
 Research, recreation like fishing and viewing, and products
like medicine, jewelry, tools, and mainly fin soup
Shark Facts
 The 1st sharks appeared on Earth 400 million years ago well before the 1st
dinosaur roamed the Earth
 Avg. life span is 25 years
 Sharks never stop growing
 Largest shark = whale shark (50 ft. long)
 Smallest shark = dwarf lanternshark (5-7 in. long)
 Fastest shark = mako shark (30 mph)
 Deepest diver = Portuguese shark (9,000 ft. or 1. 5 miles)
 Longest migration = a blue shark traveled 3,740 miles
 Only freshwater capable shark = bull shark (the Borneo river shark (Glyphis sp. B), the Irrawaddy river shark
(Glyphis siamensis), the New Guinea river shark (Glyphis sp. C), the Ganges shark (Glyphis gangeticus), the Speartooth shark (Glyphis glyphis)
 Highest note heard is 800 Hertz (or G above High C on the piano), so humans
can hear many high sounds that sharks cannot
 Lowest note heard is 10 Hertz (or 1.5 octaves below the lowest key on the
piano). The lowest note a human can hear is 25 Hertz, so we miss out on some
of the very low frequencies that sharks can detect
Man-eaters!!!
 Great white shark
 Tiger shark
 Bull shark
 Hammerhead shark
 Mako shark
 Oceanic whitetip shark
 Reef sharks, lemon shark,
blue shark, etc…
Vocabulary
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Placoid scales (dermal denticles) = small outgrowths that cover the skin of a shark similar in
structure to the teeth
Liver = organ for energy storage and buoyancy
Clasper = one of the modified, usually paired organs by which the male clasps the female during
copulation
Lateral line = sensitive receptors that detect gentle currents and vibrations
Ampullae of Lorenzini = special sensing organs forming a network of jelly-filled canals that detect
electrical fields in the water
Spiracle = provide oxygenated blood directly to the eye and brain through a separate blood vessel
Dorsal fin = fin on top that stabilizes and may provide protection
Pectoral fin = paired fins on the side that control steering and add lift as the shark swims
Caudal fin = locomotive limb at the end of a shark that propels it forward
Viviparous = live birth (get nutrients from mother not an egg)
Oviparous = eggs hatch outside the mother
Ovoviviparous = eggs hatch inside the mother then give live birth
Cloaca = opening shared by the genital organs, the urinary and intestinal tracts
Spiral valve = lower portion of the digestive tract that is internally twisted or coiled to increase the
surface area, which increases nutrient absorption
Atrium = a large muscular chamber that serves as a one-way compartment for blood that is about to
enter the ventricle
Ventricle = a thick-walled muscular chamber that pumps blood
Great white
Tiger
Bull
Great Hammerhead
Shortfin mako
Blue
Whale
Basking
Lemon
Oceanic whitetip
Nurse
Pacific angel
Australian wobbegong
Gray reef
Blacktip reef
Whitetip reef
Greenland
Spiny dogfish
Sand tiger
Thresher
Leopard
Goblin
Swell shark
Horn shark
Bonnethead