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When out fossil hunting...

So I thought I would do a post about things to remember when out and about doing your own fossil hunts, hopefully you'll find it helpfu...

Wednesday 24 August 2016

Mammalian Dentition

Diagrams of the three types of
mammalian teeth. Image credit Pearson
Education Inc.
The teeth of a carnivore consist mainly of sharp teeth. What is typical of carnivorous dentition is that there are no flat molars as these are characteristics of herbivores and omnivores. The most prominent feature of carnivorous teeth are large canines.


There are four canines in the oral cavity; two on the upper jaw (maxillary) and two on the lower jaw (mandibular). Canines are also found in omnivores including humans; however in humans the canines are much smaller. These canines act as knives that slice deep into flesh and cut chunks away. It should be noted that unlike human teeth, the teeth of a carnivore are widely spaced to prevent debris getting caught.


Carnivores have rather undeveloped molars in the sense that they are not flat and remain pointed. These molars act as scissors, slicing the flesh into smaller pieces in an up and down motion.


While herbivores and omnivores have enzymes in their saliva to aid with digestion of plants, carnivores do not possess an enzyme that breaks down proteins as they would damage the interior of the mouth. Therefore carnivores must swallow their food in chunks which requires a strong digestive system.


Carnivores have a large hole behind each eye socket; this is called the temporal fenestrae. This allows the jaw muscles to grow larger, therefore the larger the hole, the more powerful the bite. The bite of a hyena is strong enough to crush bone making it a successful scavenger, when food is scarce the animal can eat bone to survive.


Although impressive, the oversized canines of the Smilodon, or saber toothed tiger, were not strong enough to bite through bone; they were extremely fragile compared to most canines. Depictions of Smilodon hunting are usually inaccurate as the canines would be more commonly used on the throat as opposed to the shoulder or hide of its prey.


In the herbivorous mandible it is clear to see that there are no canines at all. A herbivore only possesses incisors and a large number of molars. This is because the teeth are not designed for slicing through meat but rather plant matter. Plant matter is difficult to digest which requires strong, grinding molars. This is the prototype for a herbivores oral cavity, however there are variations.


The teeth of a Woolly Mammoth for instance. They are not individual molars, the teeth were a large mass with sharp enamel ridges that were not worn down easily over the animal’s lifetime; this allowed it to eat large quantities of vegetation, making the animal successful in the colder climate.


Herbivores, unlike carnivores, can chew their food. The reason that vegetation is chewed is that it releases the digestible insides of the plant. Chewing also exposes the food to enzymes, aiding to speed up digestion.




Omnivores display characteristics of both herbivores and carnivores in the sense that they have canines and flat molars. The human canines are not very large. This is because around 3.6 million years ago, when Australopithecus afarensis first evolved, human dentition began to change. One theory suggests that Australopithecus were not as reliant on raw meat as a food source, either because they ate more vegetation or they had developed the ability to cook their meat using fire, however this theory has not been proven.


In comparison, the skull of a Chimpanzee displays much larger canines but very similar molars to that of a human’s. The reason for the difference in canine size is that Chimpanzees are still reliant on raw meat, which requires sharp teeth to tear through.

Omnivores have the same enzymes that herbivores do in order to aid with the digestion of vegetation. The stomachs of omnivores are similar to carnivores, as omnivores have to digest meat as well, as they are unable to produce the enzymes that break down protein in the mouth as it would damage the interior of the oral cavity. Therefore, omnivores and carnivores have a stomach acid that has a very low pH of 1 or 2.


Omnivores have proven to be rather successful in the wild. This is because if one source of food was to vanish, the animal could still eat the remaining source, for example if an animal that was prey to a Chimpanzee was to become extinct, it could still survive on plants until another source of meat became available.

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