Credit: Chris huh via WikiCommons CC-BY SA 3.0 Some different kinds of shark teeth include:
Shark teeth are specialized according to their diets.
#Dwarf lantern shark lifespan series#
When a tooth in one row is lost, a tooth in a further series will sometimes be pushed into its space. The bull shark has 50 rows of teeth in 7 series. The average shark has about 15 rows and 5 series on both upper and lower jaws. Shark teeth are counted in terms of rows (along the jaw) and series (from front to back). Sharks tend to replace their teeth more often when they are younger. Most sharks have around 30,000 teeth during their whole 20-30 year lifespan, typically more for the longer-lived species. In fact, an adult shark’s mouth typically has multiple rows of teeth that get pushed forward to take the place of a missing one. As such, sharks have a constant need for new teeth. These teeth are fused directly to the gums rather than the jaw so they can fall out and be removed easily. Shark teeth are primarily made of calcium phosphate. These tesserae act like armor and protect the jaws from damage. Their jaws are not actually connected to their heads and are surrounded by a layer of material called tesserae, small blocks of calcium salts. Sharks have very strong jaws and several rows of sharp jagged teeth. So far, sharks are the only kind of cartilaginous fish that is known to undergo parthenogenesis, meaning that the female can conceive asexually without the sperm of a male. Most sharks reach sexual maturity around 13-15 years of age and typically only rear a few well developed young. These electroreceptors assist them in locating prey. Receptors near the nose called the ampullae of Lorenzini detect electrical signals. They are even able to sense electromagnetism generated by living organisms. Combined with their good hearing, sharks are very effective predators. They can tell where their prey is by the timing and intensity when the scent hits each nostril (similar to human hearing). They have an extraordinarily sensitive sense of smell that can detect blood in water at concentrations as low as one part per million. Sharks are known for being fierce hunters and are generally the apex predator for their environment.
#Dwarf lantern shark lifespan skin#
The skin both helps them move through water more quickly and anchors their swimming muscles to take strain off the skeleton. The collagen fibers are what gives shark skin its recognizable rough textured feel. Shark scales are made of fibers of collagen (the same stuff in human skin) that are crisscrossed in a helix shape across their whole body. Sharks also have different scales than those of bony fish. The lighter skeleton helps the shark save energy by reducing its weight.Ī drawing of the skeleton of a Great White Shark. Shark cartilage is very flexible yet durable even though it is only half the density of normal bone.
Where most kinds of fish have a bony skeleton, sharks instead have a skeleton made of almost entirely cartilage and connective tissue. Shark skeletons are very different from those of other ichthyoids. Most sharks are saltwater but a few species live in both salt and freshwater.
Sharks find a home in all the Earth’s oceans and live at mid-level depths, normally around 6,000 ft. Sharks range in size from the 17 cm dwarf lantern shark ( Etmopterus perryi) to the massive 40-foot long whale shark ( Rhincodon typus). Sharks are characterized by their cartilaginous skeletons, dorsal gills, and freestanding pectoral fins. The term “shark” is normally used to refer to any fish in the Selachimorpha superorder. The exact shape and size of teeth tell us what kind of food they eat and help us trace out their life cycle and migration patterns. Analyzing shark teeth can also tell us a lot about the habits and diets of sharks. Fossilized shark teeth can give evolutionary biologists clues about the evolution and biology of sharks. In fact, shark teeth are the only part of a shark that will fossilize. Shark teeth are a common find among fossil collectors due to their high amounts of calcium and phosphate minerals. Credit: General Wesc via WikiCommons CC-BY 2.0
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