The shark can sense frequencies in the range of 25 to 50 Hz. It detects motion or vibrations in water. This system is found in other fish as well. In bony fish and tetrapods the external opening into the inner ear has been lost. This and the sound-detecting organs are grouped together as the 'acoustico-lateralis system', because they have a common origin. It is open to the environment by a line of pores. The lateral line detects changes in water pressure. A small opening on each side of their heads (not the spiracle) leads directly into the inner ear through a thin channel. HearingĪlthough it is hard to test sharks' hearing, they may have a sharp sense of hearing and can possibly hear prey many miles away. Sharks may use this sense when they catch their prey, even more than they use their sight. These tiny electric currents make signals that travel through water and get sensed. Animal in the water give off electricity: every time an animal's heart beats or it moves, tiny currents of electricity are made. p23 They can sense electricity in the water. In them are which are nerve receptors called the ampullae of Lorenzini. Sharks have tiny holes all over the shark's snout, especially between the eye and the tip of the snout. Senses SmellĮlectromagnetic field receptors (Ampullae of Lorenzini) and motion detecting canals in the head of a shark However, the fastest swimming sharks (such as the Mako sharks) tend to have lunate-shaped (crescent-shaped) caudal fins. The strong, non-lunate caudal fin in most benthic shark species allows the shark to swim close to the seabed (such as the Nurse shark). The pectoral fins and the shape of the body (like an airfoil) work together to counter this force. The upper lobe of the caudal fin produces the most amount of the push, and usually forces the shark downwards. The primary use of the caudal fin is to provide a "push" while the shark swims. The caudal fin has both, an upper lobe, and a lower lobe, that can be of different sizes and the shape depends of which species the shark is. The peduncle may also be horizontally flattened into lateral keels. The caudal peduncle sometimes has notches known as "precaudal pits", which are found just ahead of the caudal fin. The tail region itself consists of the caudal peduncle and the caudal fin. Not all sharks have anal fins, but if they do have them, they are found between the pelvic and caudal fins. The pelvic fins are located behind the pectoral fins, near the claoca, and are also stabilizers. These fins are used for steering during swimming and help to provide the shark with lift. The pectoral fins are located behind the head and extend outwards. When spines are present, they are used for defensive purposes, and may also have skin glands with them that produce an irritating substance. These two fins may, or may not have spines. These fins help the shark from constantly rolling around. There are one or two fins present along the dorsal midline called the first and second dorsal fin. The fins of sharks are used for stabilizing, steering, lift and swimming. Sharks' teeth can be 20 times as big as human teeth and they can grow back if they are lost. If you rub along a shark towards the tail, it would feel smooth, but if you rub the other way, it would be rough. Sharks have skin covered in millions of tiny teeth-like scales that point to the tail. Every inch of tooth equals 10ft of shark length: so if a shark tooth is 2 inches long, the tooth came from a shark that was 20 ft long! Even more terrifying is that some of the Megalodon teeth are 6 inches long so that suggets a shark 60 feet long. Shark teeth collectors can guess how large a shark was by measuring the shark tooth! First, they measure the length of the tooth in inches. Because there are so many different kinds of sharks, and because each kind has its own kind of special teeth, many people enjoy collecting shark teeth. For instance, some sharks have sharp, pointy teeth, while bottom dwelling sharks have cone-shaped teeth for crushing shells. Sharks have different-shaped teeth, depending on what they eat. This is why a shark does not eat every day. This is pretty slow, however, so a meal might take several days to digest. The chunks of food that a shark swallows ends up in its stomach, where they are digested. So they bite their prey and jerk it around so they can pull of a chunk to swallow. Even with all those teeth, though, sharks can not chew.
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