Dentition
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tusks
Ivory Page
Ivory  Links Page

Did you know?

  • The tusks are actually upper incisors, not canines. They are the only incisors the elephant has...
  • Tusks are used for digging, ripping of bark, foraging, resting a heavy trunk, and as weapons
  • Tusks are fundamentally no different than ordinary teeth
  • Both sexes of the African elephant have tusks, but only the male sex of Asian elephants have tusks that protrude beyond the lips.
  • One of the elephant's tusks is often used more than the other
    ( i.e. the parallel in humans is right handed and left handed people)

Elephants are best known by many people in the world for their teeth. It is because of the human lust for ivory that thousands of people and countless elephants have been slaughtered for their teeth. Ivory is really only dentine and is no different from ordinary teeth. It is the diamond shaped pattern of the elephant's tusk looking from a cross-section which gives elephant ivory its distinctive lustre.

The tusks present at birth are only milk teeth which fall out after around one year of age (approximately 5 cm long). The permanent tusks begin to protrude beyond the lips of an elephant at around 2-3 years of age, and will continue to grow  throughout its life. Were and elephant's tusks able to grow long enough they would be in the shape of a spiral (similar to the extinct woolly mammoth), because the tusk typically follows a sinusoidal curved growth pattern. The growth rate of tusks is at approximately 15-18 centimeters per year.

About one quarter of the tusk is hidden within the socket. Thus, the typical question of why people can not just cut off the elephant's tusks to ward off poachers is answered. There is still a large amount of ivory that is attached inside the head and attached to the skull, which has to be carved out of the head to be removed.

The actual base of the tusk is hollow and contains the pulp cavity. This usually extends quite far, and in males may reach beyond the lip line. The tusk grows from its base as fresh dentine is slowly deposited over the surface of the pulp cavity. Interestingly, for females this cavity begins to fill in with age.  The pulp is composed of a highly vascular tissue (blood vessels and nerves), which is amongst unspecialized connective tissue.

Although both African elephant sexes have tusks, there are large differences in size and weight. Typically, the male tusk has a larger circumference in relation to its length, is stouter, and is much heavier. Interestingly, some elephants are born without tusks. This hereditary condition causes huge differences in the musculature and shape of the neck and the head. Also, the carriage of the head is different and the bones at the back of the skull are less developed. Interestingly, not all male Asian elephant elephants have tusks; approximately 40-50 percent of male Asian elephants are tuskless. These particular males are known as makhnas in India. Some likely reasons for the greater proportion of tuskless Asian elephants compared the African elephants may be due to strong selection in the past by humans killing the tusked male elephants and an gene in Asian elephants which is not as recessive.

Resting A TrunkWhen fully developed the Asian elephant's tusks does compare to the weight and size of the African elephant's tusks. The tusks of a male African elephant may exceed 200 kg for the pair although such weights are rare today because most of them have been murdered. The heaviest tusks recorded were 209 kg for the pair taken from an old bull shot in 1897 (British Museum of Natural History).

The working tusks that an elephant favours tends to be more worn down over the years. The tusks server a variety of functions for an elephant; this is for digging up soil at salt licks, ripping off bark from trees, for resting a heavy trunk, and as weapons.

Dentine / Teeth
Teeth

Did you know?

  • The total number of teeth an elephant has is 24
    (six in each half jaw)
  • No more than two of the six teeth are in wear at the same time in each side of a jaw (the only exception is in young elephants which may use three)
  • Teeth grow from the back of the jaw and follow a linear pathway of movement forwards as the preceding tooth is progressively worn down in the front.
  • Each tooth drops out as it reaches the front of the elephant's jaw.

The elephant's teeth are very unique in the manner in which they proceed from the back of each half jaw towards the front. The teeth follow a linear progression. As the front teeth continuously become more worn down they are slowly replaced with new teeth that give the elephant an ability to chew the coarse foods it ingests.

This peculiar eruption of teeth may be related to the comparatively long growth period the elephant goes through. The jaw of a young elephant is much smaller than that of an adult making permanent teeth early in life a death sentence to a growing animal that needs the ability of teeth to survive. Incidentally, most other mammals have a much quicker growth rate which solves this problem because the milk teeth can suffice for the duration of this growth period.

Teeth CloseupThe molars in the elephant vary between the two main species. Both have a series of ridges (laminae) which run across the tooth. However, in the Asian elephant the ridges are parallel as opposed to the diamond shaped ridges in the African elephant. Interestingly, despite having grazing teeth, the Asian elephant is considered to be primarily a forest animal (Elephants)

The movement of the elephant's jaw during chewing is forwards and backwards, unlike cows who use sideways movements to chew this cud. Hence, the ridges act as two rasps grating upon one another and is made more effective by the teeth being slightly curved along the lengths.

When an elephant is born it has four developing teeth in each side of the calf's jaws. This consists of their fairly small first and second tooth which are present after birth, the end of a third and a forth which is still below the gum.

As mentioned, as a tooth wears it is pushed forward: to the front mouth and it slowly wears inyo a shelf  as the roots are absorbed (Elephants P.50). The shelf eventually will break off and the remaining fragment will be pushed out of the mouth. Interestingly, the absorption of tooth roots is a phenomenon which is found to take place after an injury or in old aged mammals. After the first two teeth are gone, parts of the two adjacent teeth are being worn down in each half of the jaw. This process proceeds as the chart below shows until the 6th and sometimes 7th molar appears. The 6th molar weighs on average a stunning 4 kg and has a maximum grinding length of 21cm ( and a width of 7cm). This 6th molar will be present for around 2/5 of the elephants life, and for many once it is finished the elephant will die (Elephants P.50). The frequency of the presence of a 7th molar ranges dramatically from 1 in 100 to 1 in 2000 depending on the area and it is also difficult to get a good sample size due to the killings of younger and younger elephants for their ivory.

Molar

Molar
Appearance

Molar
Loss

I

birth

2 years

II

birth

6 years

III

1 year

13-15 years

IV

6 years

28 years

V

18 years

43 years

VI

30 years

65+ years

** Laws 1966 listed in Elephants

As an elephant gets older one of the most limiting factors in its ability to live a longer life is the teeth. Once the last molar the elephant has wears out it is incapable of chewing its food properly and either death from starvation or malnutrition will occur. Interestingly, about 10% of the older aged elephants will have and additional seventh molar, but it is never as developed as the others.

 

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