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"Typical sharks", such as requiem sharks, have tails with the upper lobe longer than the lower. The upper lobe is turned upwards at a moderate angle relative to the body, which balances cruising efficiency with turning ability. The thresher sharks have an extreme example of this tail in which the upper lobe has evolved into a weapon for ...
Baleen whales have two blowholes positioned in a V-shape, while toothed whales have only one blowhole. [6] The blowhole of a sperm whale , a toothed whale, is located left of centre in the frontal area of the snout, and is actually its left nostril, while the right nostril lacks an opening to the surface and its nasal passage is otherwise well ...
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.
The entire body of a shark is a very efficient eating machine. Each organ has been fine-tuned for hunting and acquiring food.
In elasmobranchs (sharks and rays) the spiracle bears a small pseudobranch that resembles a gill in structure, but only receives blood already oxygenated by the true gills. [7] The function of the pseudobranch is unknown, but it is believed that it supplies highly oxygenated blood to the optic choroid and retina and may have baroreceptor ...
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.
[12] [13] The thresher shark has a short head and a cone-shaped nose. The mouth is generally small, and the teeth range in size from small to large. [ 14 ] By far the largest of the three species is the common thresher , Alopias vulpinus , which may reach a length of 6.1 metres (20 ft) and a mass of over 500 kilograms (1,100 lb).
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.