Shark: The Apex Predator of the Sea
They glide through the water with unmistakable grace. Remnants of an ancient past, they dive and they rise, from the ocean's murky depths to its sun-kissed shallows. Rousing fear and awe like no other creature in the sea.
Sharks have been around since prehistoric days. These incredible animals not only outlived the dinosaurs, they evolved to the very top of the marine food chain. The are world's biggest living fish is a shark. Of the estimated 34,000 species of
fish, the largest are whale sharks. These gentle giants usually grow to about
40 feet long and weight estimated 15 tons. Their mouth alone can span four feet
wide. The gigantic whale shark however, pales in comparison to the largest fish
that ever existed, the megalodon. Dating to over 20 milions years ago, it's
thought that the prehistoric shark could have reached 80 feet long, weighing up
to around 70 tons. Unlike whale sharks, the megaldon was carnivorous, and
consumed any creature that fit into its nearly 10 feet wide mouth.
Throughout
their lives some species of shark can shed over 30,000 teeth. Unlike humans who
are born with a set number of teeth in their jaws, Sharks have a seemingly
limitless supply. They can grow, lose, and replace their teeth as needed.
Furthermore, most sharks have multiple rows of teeth in their jaws. The jaws of
a great white shark, the largest predatory fish in the sea, can contain up to
seven rows that hold up to 3,000 teeth at any point. Most sharks, as they hunt
their prey, end up losing their teeth individually. However, the cookiecutter
shark loses and replaces the teeth in it's lower jaw all at once.
Sharks are built for speed. The fastest known shark, the mako shark, can reach speeds of up to 46 miles per hour. This speed is largely due to their body's hydrodynamic design. Many sharks have torpedo shaped heads that allow them to cut through the water with little resistance. Plus, shark skin is covered with flat, v-shaped scale, called dermal denticles. The denticles help water flow smoothly over the skin, which reduces friction and helps sharks swim quickly and quietly. Sharks also have skeletons made of cartilage instead of bone. cartilage is a much lighter material than bone. Some sharks have less weight to carry.
Shark
may lay eggs or bear live young. Egg laying sharks only lay a few large eggs.
They may come in various forms, such as sacks called mermaid purses of
corkscrews. These eggs act as external wombs in which shark embryos complete
their development. However, most sharks give birth to live young. Called pups,
the young of most live bearing species gestate for around one year. Some even
begin practicing their predation skills while in the womb. Before they are
born, the sand tiger shark pups compete with their siblings., In fact, the
strongest pup in each of the two wombs devours its weaker brothers and sisters.
Some
sharks are at risk of extinction. Every year an estimated 1,000 milliion sharks
are killed worldwide, in large part for the shark fin trade. the sharks are
caught and their dorsal fins are removed and sold at a hefty price, primarily
in Asia. In traditional Chinese culture serving and eating shark fin is a sign
of status and wealth. Because of the high demand and value of shark fins, some
shark populations have plummeted by up to 705 causing a ripple effect in
ecosystems and endangering at least 74 shark species. However, measures are
being taken to protect sharks with a number of countries and jurisdictions
cracking down on unsustainable shark fishing. In China, shark fin soup is no
longer allowed to be served at government banquets. A move hailed by shark
conservationists. Through continued international conservation efforts, the
loss of sharks may be curbed, allowing the creatures in all their power and
grace to survive for many generations to come.
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