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The thresher sharks have an extreme example of this tail in which the upper lobe has evolved into a weapon for stunning prey. Bottom-dwelling sharks such as catsharks and carpet sharks have tails with long upper lobes and virtually no lower lobe. The upper lobe is held at a very low angle, which sacrifices speed for maneuverability.
Blacknose sharks are preyed upon by larger sharks, [7] and captives have been observed to perform an apparent threat display towards encroaching divers or newly introduced members of their species. The display consists of the shark hunching its back, lowering its pectoral fins, gaping its jaws, and swimming with an exaggerated side-to-side motion.
The daggernose shark (Isogomphodon oxyrhynchus) is a little-known species of requiem shark, in the family Carcharhinidae, and the only extant member of its genus.It inhabits shallow tropical waters off northeastern South America, from Trinidad to northern Brazil, favoring muddy habitats such as mangroves, estuaries, and river mouths, though it is intolerant of fresh water.
Many sharks can contract and dilate their pupils, like humans, something no teleost fish can do. Sharks have eyelids, but they do not blink because the surrounding water cleans their eyes. To protect their eyes some species have nictitating membranes. This membrane covers the eyes while hunting and when the shark is being attacked.
With his hand close to razor sharp teeth, shark expert Neil Harvey attempts tonic immobility in a large reef shark. Tonic can be induced by turning a shark upside down, but that's not the only way.
The broadnose sevengill shark (Notorynchus cepedianus) is the only extant member of the genus Notorynchus, in the family Hexanchidae.It is recognizable because of its seven gill slits, while most shark species have five gill slits, with the exception of the members of the order Hexanchiformes and the sixgill sawshark.
Shark bites are common in Volusia County, with blacktips and bull sharks mostly to blame. But the bites are rarely fatal. Here is what we know.
"We have to think about it in terms of the food web that's out in the ocean: Ultimately, at the very top of that cycle of life are the sharks and if we removed the sharks, smaller fish species ...