How the last 12,000 years have shaped what humans are today

While humans have been evolving for millions of years, the past 12,000 years have been among the most dynamic and impactful for the way we live today, according to an anthropologist who organized a special journal feature ...

Early humans: Tooth enamel reveals life histories

If you take a magnifying glass and a flashlight and look at your teeth very carefully in the mirror, in places you can spot a pattern of fine, parallel lines running across your teeth. These correspond to the striae of Retzius ...

Dinosaur teeth reveal what they didn't eat

Scratches on dinosaur teeth could reveal what they really ate. For the first time, dental microwear texture analysis (DMTA) has been used to infer the feeding habits of large theropods, including Allosaurus and T. rex.

Neanderthals may have been carnivores, according to new study

A new study published on October 17 in the journal PNAS, led by a CNRS researcher, has for the first time used zinc isotope analysis to determine the position of Neanderthals in the food chain. Their findings suggest that ...

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Tooth

Teeth (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.

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