Tooth
hideTeeth (singular tooth) are small whitish structures found in the jaws (or mouths) of many vertebrates that are used to tear, scrape, and chew food. Some animals, particularly carnivores, also use teeth for hunting or defense. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of tissues of varying density and hardness.
Teeth are among the most distinctive (and long-lasting) features of mammal species. Paleontologists use teeth to identify fossil species and determine their relationships. The shape of the animal's teeth are related to its diet. For example, plant matter is hard to digest, so herbivores have many molars for chewing. Carnivores, on the other hand, need canines to kill prey and to tear meat.
Mammals are diphyodont, meaning that they develop two sets of teeth. In humans, the first set (the "baby," "milk," "primary" or "deciduous" set) normally starts to appear at about six months of age, although some babies are born with one or more visible teeth, known as neonatal teeth. Normal tooth eruption at about six months is known as teething and can be painful.
Some animals develop only one set of teeth (monophyodont) while others develop many sets (polyphyodont). Sharks, for example, grow a new set of teeth every two weeks to replace worn teeth. Rodent incisors grow and wear away continually through gnawing, maintaining relatively constant length. Many rodents such as voles (but not mice) and guinea pigs, as well as rabbits, have continuously growing molars in addition to incisors.
For more information about Tooth, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with teeth
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Study Pits Man v Machine in Piecing Together 425-Million Years Old Jigsaw
Other Sciences / Archaeology & Fossils
Nov 16, 2009 |
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(PhysOrg.com) -- A new study pitting academic expertise against a computer in recreating a 425 million-year old jigsaw puzzle has discovered that there is no substitute for wisdom born out of experience.
Plesiosaur a victim of shark attack
Other Sciences / Archaeology & Fossils
Oct 06, 2009 |
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(PhysOrg.com) -- An 85 million-year-old plesiosaur fossil has been found with over 80 shark's teeth, suggesting the animal was the victim of sharks in a feeding frenzy. The find is perhaps the most spectacular example of ...
53 million-year-old high Arctic mammals wintered in darkness
Space & Earth / Earth Sciences
Jun 01, 2009 |
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(PhysOrg.com) -- Ancestors of tapirs and ancient cousins of rhinos living above the Arctic Circle 53 million years ago endured six months of darkness each year in a far milder climate than today that featured ...
Scientists discover why teeth form in a single row
Feb 26, 2009 |
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(PhysOrg.com) -- A system of opposing genetic forces determines why mammals develop a single row of teeth, while sharks sport several, according to a study published today in the journal Science. When comple ...
Among Apes, Teeth Are Made for the Toughest Times (w/ Video)
Dec 16, 2009 |
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(PhysOrg.com) -- The teeth of some apes are formed primarily to handle the most stressful times when food is scarce, according to new research performed at the National Institute of Standards and Technology. The findings ...
Study of baby teeth yields new findings on nuclear fallout
Oct 21, 2009 |
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Joan Ketterer still recalls the button her son Edward got for donating his baby teeth to what was then a ground-breaking study looking at the effect of nuclear fallout on children born in the St. Louis-area in the 1960s.
Open wide and say 'zap'
Aug 18, 2009 |
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A group of researchers in Australia and Taiwan has developed a new way to analyze the health of human teeth using lasers. As described in the latest issue of Optics Express,, by measuring how the surface of a tooth respon ...
Dino tooth sheds new light on ancient riddle
Other Sciences / Archaeology & Fossils
Jun 29, 2009 |
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Microscopic analysis of scratches on dinosaur teeth has helped scientists unravel an ancient riddle of what a major group of dinosaurs ate- and exactly how they did it!
Fossil bone bed helps reconstruct life along California's ancient coastline
Other Sciences / Archaeology & Fossils
Jun 08, 2009 |
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In the famed Sharktooth Hill Bone Bed near Bakersfield, Calif., shark teeth as big as a hand and weighing a pound each, intermixed with copious bones from extinct seals and whales, seem to tell of a 15-million-year-old ...
Ancient mammals shifted diets as climate changed
Other Sciences / Archaeology & Fossils
Jun 03, 2009 |
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A new University of Florida study shows mammals change their dietary niches based on climate-driven environmental changes, contradicting a common assumption that species maintain their niches despite global ...
Focus on the formation of bones, teeth and shells
Nanotechnology / Bio & Medicine
May 14, 2009 |
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Researchers at Eindhoven University of Technology for the first time have shown the earliest stages in biomineralization, the process that leads to the formation of bones, teeth and sea shells.
Researchers Crack the Mystery of Resilient Teeth
Apr 17, 2009 |
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(PhysOrg.com) -- After years of biting and chewing, how are human teeth able to remain intact and functional? A team of researchers from The George Washington University and other international scholars have ...
Coke ads 'totally unacceptable' in Australia
Apr 02, 2009 |
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Australia's consumer regulator has ordered Coca-Cola to publish corrections after it claimed in "unacceptable" ads that health risks from the soft drink were a myth, the watchdog said Thursday.
Study: White wine can make tooth stains darker
Apr 01, 2009 |
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It has long been known that red wine causes teeth to stain. But white wine? A recent study by NYU dental researchers found that drinking white wine can also increase the potential for teeth to take on dark stains.
Flossing monkeys 'proof' animals teach tool use
Mar 11, 2009 |
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Thai monkeys have been observed showing their young how to floss -- proof primates teach offspring to use tools, a Japanese researcher said Wednesday.
