• sharks never get cancer
• sharks never go blind
• they show no loss of brain activity as they get older
• they can't swim backwards
• sharks are attracted to churning water and bright colors
• they have skeletons made more of cartilage than bone
• their teeth are continually renewed: as one breaks off, another rotates into its place; each tooth is replaced every one or two weeks
• sharks are slightly heavier than water; they will slowly sink if not swimming
• instead of scales, sharks are covered with denticles that are abrasive and have the same structure as teeth
• sharks can learn: in controlled experiments they have learned to press a button in order to receive food
• average shark attacks per year: 50
• average fatalities per year: 6
• female sharks usually grow to be larger than the males
• a favorite food among sharks is shark pups: it is often difficult to get recently captured sharks to begin eating normally, and this is sometime remedied by giving them live baby sharks or shark liver
• sharks are so sensitive to smells that they have been able to detect grouper flesh in dilutions of only one part in 10 billion parts seawater
• they have excellent vision
• sharks can locate their prey on the open sea by detecting the minute electrical fields they generate. in addition to ears they also have an acute sense of vibration

• "Isurus oxyrinchus"
• common names: shortfin mako, bonito shark, and blue pointer
• makos live in all tropical and warm temperature seas, swimming from near the surface to moderately deep waters
• under normal conditions, makos will grow up to 13 feet
• they are metallic blue on top and snow white beneath
• makos attack swiftly with huge grasping teeth; the teeth are visible even when their mouths are closed.
• the world game fishing record for makos is a 136", 1080 lb shark caught off the coast of Montauk, New York on August 26, 1979 by J.L. Melanson
• makos are cannibals while still in the womb; older embryos will eat the younger embryos and eggs
• makos are the fastest swimming shark and one of the fastest swimming fish; they have been known to swim at speeds up to 22 mph -- one is known to have traveled 1,322 miles in 37 days, an average of 36 miles a day
• makos are probably the most prized game fish; they put up furious resistance; featured in Hemingway's novel The Old Man and the Sea, they are capable of 20 foot leaps in the air when hooked, and are known to leap into boats when hooked

Tiger Sharks:

• generally grow up to 18 feet long, but may get as big as 24 feet
• they are named for the dark stripes on their grey backs, which are especially pronounced on juveniles
• tiger sharks are maneaters, second only to the great white shark in the number of known attacks on people and boats
• their large mouths and fearsome teeth allow them to eat almost anything: they have eaten cattle, pigs, donkeys, sheep, garbage, and humans that have fallen overboard
• one giant weighed over 6500 pounds