ALL ABOUT SHARK

 

Sharks are fascinating and ancient marine predators that have existed for over 400 million years, predating even the dinosaurs! Here’s everything you need to know about them:

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1. Classification and Types

Sharks belong to the class Chondrichthyes (cartilaginous fish) and the subclass Elasmobranchii, which includes rays and skates. There are over 500 species of sharks, categorized into different groups:

Major Types of Sharks:

• Great White Shark (Carcharodon carcharias) – The ocean’s most famous apex predator.
• Hammerhead Sharks (Sphyrnidae) – Known for their distinctive head shape, which enhances sensory perception.
• Tiger Shark (Galeocerdo cuvier) – A large, aggressive species that eats a wide variety of prey.
• Whale Shark (Rhincodon typus) – The largest shark, but a gentle filter feeder.
• Bull Shark (Carcharhinus leucas) – Can survive in both fresh and saltwater.
• Mako Shark (Isurus) – The fastest shark, reaching speeds up to 74 km/h (46 mph).

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2. Anatomy and Features

• Cartilaginous Skeleton – Unlike bony fish, sharks have skeletons made of cartilage, making them lighter and more flexible.
• Multiple Rows of Teeth – Sharks constantly shed and replace teeth throughout their lifetime.
• Electroreception (Ampullae of Lorenzini) – Special sensory organs help them detect electrical signals from prey.
• Dermal Denticles – Their skin is covered in tiny, tooth-like structures, reducing drag and allowing for swift swimming.

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3. Habitat and Distribution

• Sharks are found in every ocean and can live in coastal waters, deep-sea environments, and even freshwater (e.g., bull sharks in rivers).
• Some species, like the great white shark, prefer cool, temperate waters, while others, like reef sharks, thrive in tropical regions.

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4. Diet and Hunting Techniques

Sharks are opportunistic feeders and have a variety of hunting methods:

• Apex predators (e.g., great white sharks) hunt seals, fish, and even dolphins.
• Filter feeders (e.g., whale sharks) consume plankton and small fish.
• Scavengers (e.g., tiger sharks) eat carrion and even non-food objects.

Hunting Strategies:

• Ambush predators (e.g., great whites) use stealth and speed.
• Social hunters (e.g., hammerheads) may hunt in packs.
• Lurking predators (e.g., angel sharks) wait for prey to pass by before striking.

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5. Reproduction and Lifespan

• Sharks have three types of reproduction:
  1. Oviparous (egg-laying) – Some sharks, like catsharks, lay eggs in protective cases called "mermaid’s purses."
  2. Viviparous (live birth) – Species like bull sharks give birth to live young.
  3. Ovoviviparous (egg-hatching inside the mother) – Great white sharks hatch internally and are born alive.
• Lifespans vary by species:
  • Great white sharks live about 70 years.
  • Whale sharks can live over 100 years.
  • Greenland sharks are the longest-living vertebrates, with some estimated to be over 400 years old!