Tuesday, December 13, 2016

#ElephantTuesdays: the elephant´s teeth 🐘

Although there might be voices against it, elephants are assumed to be generalized grazers in the wild. Their feeding preferences are attributed to different factors like season or habitat; the conversion from woodland to grassland as a result of habitat degradation leads the elephant feeding habits from browsing (feeding on leaves, soft shoots, or fruits of high-growing, generally woody, plants such as shrubs) to grazing (feeding on grass).

Their food intake varies in percentage, and the most prevalent food is reported to be grass. But they also eat shrubs, leaves, twigs, roots, fruits, seeds, herbaceous plants, soil and stones (incidentally swallowed with soil).

The elephant´s oral cavity is actually fairly small compared to its body size. The tongue is unable to protrude from the oral cavity as the tip is attached to the floor of the mouth. The tongue can form a fold in the center that helps pushing the food into the end of the mouth:

Young elephants develop deciduous tusks that provide the orientation of the future permanent tusks. Tusks are observed both in female and male in African elephants, and in male Asian elephants, although female Asian elephants may as well develop short vestigial tusks called tushes that often won´t come out completely. 

checking Buria´s (an Asian female) tusk cavity for tushes

Elephant´s teeth erupt from the back to the front (horizontally). They have 6 sets of molars during their whole life (they undergo dentition 6 times!!), and when one tooth breaks off, another one pushes forwards to replace it. Their teeth are made up of ridges (lamellae) and when these lamellae are old and worn down, they need to break to fall down, and this is one of the reasons why wood is an important part of their food intake, playing an essential role in the elephant´s teeth regeneration. By chewing hard branches and bark, a lamella breaks off and falls down or is swallowed until the whole tooth is replaced by the next molar coming from the back (broken molars of elephants can be found on the ground or in their dung). Once all their teeth break off, the elephant will die of starvation (or malnutrition). In fact, if elephants kept in zoos are wrongly fed, for instance if they are not given branches daily, they will suffer from teeth deformations as well.

Eating bark and branches is not only important when it comes to teeth regeneration, but also elephants can easily take profit of its nutrients; unlike humans, they possess specialized digestive systems and the necessary enzymes to break down huge macromolecules like cellulose into smaller molecules that can be assimilated.  

Original video: ACP000chqq

Sometimes they don´t eat it, but use it as a tool instead. In the video below, the elephant keeps a piece of wood between its trunk and tusk to use it later:

Original video: ACP000cgv8

There are considerable differences between the Asian and the African elephant teeth, with the lamellae being diamond-shaped in Africans and parallel in AsiansGuess which species it is in the picture below (*).


As a curiosity:  the elephant´s first molar is so big as a matchbox, and the last one (6th) is as big as a brick. 

*it is an African elephant πŸ‘


Murray E. Fowler, Susan K. Mikota (2006): Biology, Medicine, and Surgery of Elephants

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