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Shark Anatomy
What makes a shark a shark? Sharks are a type of marine fish with skeletons of cartilage rather than hard bone. Cartilage is lighter and more flexible than bone, allowing sharks to move and turn quickly in water. The lighter cartilaginous skeleton also helps sharks stay afloat. Most fish have a swim bladder that increases buoyancy, but sharks lack this anatomical feature and sink if they do not keep moving. Like other fish, sharks breath with a set of gills and oxygenate the blood by absorbing dissolved oxygen in the water through special brachial arteries.
Shark reproduction varies by species and can be oviparous (egg-laying), vivaparous (internal embryo development and live birth), and ovoviviparous (eggs develop and hatch inside the female).
Diets and feeding habits vary according to species. Most sharks feed on smaller fish and squid. Some larger sharks feed on sea mammals, such as dolphins and seals. Sharks are also opportunistic eaters and will often dine on whatever is available, even if it is outside their usual diet. Shark teeth are organized by rows and series. Unlike human teeth, which are replaced once, shark teeth are continuously lost and replaced, which helps keep them sharp. |