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Some Tidbits About Sharks
More About the Great White
Some Tidbits About Sharks
The biggest shark species has the smallest teeth. The 12 metre long whale
shark has more than 4,000 teeth, each only 3mm long.
The shark is the only fish that can blink with both of its eyes..
It has long been believed that Great White sharks spend most of their
lives near shore pursuing seals and sea lions, but a report in this week's edition of the journal Nature indicates that the
awe-inspiring predators range across vast stretches of the open ocean. In fact, one male tagged along the Central California
coast migrated thousands of miles to the waters off Hawaii - and remained there for nearly four months. "Until this study,
white sharks had only been tracked for a few days around seal colonies. With the advent of new electronic tagging technology,
we can now track their movement, depth and temperature preferences over many weeks and months" said Barbara A. Block, who
is a professor of biological sciences at Stanford's Hopkins Marine Station in Pacific Grove, CA. The electronic tags recorded
data every two minutes on water depth, temperature and light. "Light-level data allow you to calculate when sunrise and sunset
occurs," said PRBO biologist Peter Pyle. "From the light data, we can calculate the longitude and latitude of the fish on
Earth."
Great White Sharks grow about 10 inches per year. Great Whites can grow
to mature lengths of 12 to 14 feet.
The average life span of a shark is 25 years, but some sharks can live to be 100.
Sharks have no bones. A shark's skeleton is made up of cartilage.
Sharks first appeared in the fossil record over 400 million years ago.
A significant physical trait that separates a modern shark from an ancient shark is the protrusile jaw, which gives the modern
shark more biting force.
A shark's skin is embedded with dermal denticles, which resemble teeth. Dried shark skin
(shagreen) was used in the past as sandpaper. In Germany and Japan, shark skin was used on sword handles for a non-slip grip.
New teeth are constantly being formed in rows in a shark's jaw. Shark's teeth are normally replaced every eight days.
Some species of sharks can shed as many as 30,000 teeth in their lifetime. Whale Sharks have approximately 300 rows of teeth,
with hundreds of tiny teeth in each row.
The largest Great White Shark ever caught measured 37 feet and weighed
24,000 pounds. It was found in a herring weir in New Brunswick in 1930. The harmless Whale Shark, holds the title of largest
fish, with the record being a 59-footer captured in Thailand in 1919.
More About The Great White
Known to scientists as Carcharodon carcharias, the
great white shark is one of the most feared predators on Earth. Spanning up to 20 feet (6 meters) and weighing up to 4,000
pounds (1,800 kg), it is built to kill.
It primarily likes seals, sea lions, turtles, smaller sharks,
and other fine-flavored denizens of the deep. If you're an animal on that list and a great white gets a whiff of your succulent
aroma, you're in a sea of trouble.
Great whites have a highly acute sense of smell. Their
nostrils, called nares, aren't used for breathing--that's what gills are for. Instead, white sharks use their nares to sniff
the water, picking up scents at a distance of a quarter-mile (0.4 km) or more, and then tracking them to their source.
A big part of every great white's brain is dedicated to
sniffing. If you're a prey animal and you're bleeding, don't bother looking for a Band-Aid. A great white can smell extremely
small amounts of blood in the water from a long way off--and it figures wounded prey is easy prey.
The great white's eyesight is also excellent for hunting.
Like cats, great whites come equipped with a tapetum lucidum (literally, "bright carpet"), a special reflective layer
behind the retina that magnifies light and enables the shark to hunt in the dark. This adaptation makes shark eyes several
times more light-sensitive than human ones.
Great whites even have extra shark-senses to help them
zero in on dinner. Their snouts are dotted with small pits, called ampullae of Lorenzini, that detect the electrical fields
of fish and other creatures. And, running in a "lateral line" down each side of their bodies are motion sensors. Great whites
can still sense what they can't see.
Still, the great white's real weapon of bass destruction
is a terrifying set of teeth, which can grow to a length of three inches (8 cm). Shaped like triangular, serrated blades,
they're arranged in six rows of around 26 teeth each, though these numbers can vary from specimen to specimen. A great white
sheds and regrows its teeth throughout its life, ensuring a fresh and healthy supply for every feeding frenzy.
A great white's bite packs tremendous power, and in the
case of larger and potentially dangerous prey, it typically takes one bite, retreats, and waits for the animal to bleed to
death before settling down to dinner. They're fearsome predators, no doubt. But they're more into ambush attacks than epic
battles between creatures at sea.
Scary as they are, we probably have less to fear from great
whites than they have to fear from us. They're now protected under the Convention on International Trade in Endangered Species.
Meanwhile, shark attacks on humans are rare. Statistics say you're more likely to get zapped by lightning--or killed by a
deer crashing into your car--than you are to be mercilessly hunted by a shark.
--Jeffery Vail
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