Primate Dentitions

Lemurs live on the Comoro and Madagascar Islands exclusively in the trees, in mostly rain forest and tropical environments, but some lemurs make their homes in hot and dry areas as well. The densest population of lemurs can be found in overgrown forest areas where there is more food during the rainy season. Lemurs survive on a variety of foods such as fruit, leaves, flowers, tree bark, and tree sap. Throughout history, lemur’s diets have shaped their teeth comb, which consist of six teeth, (four incisors and two canines). The lemur’s dentition is heterodont (having multiple tooth morphologies) and derives from an ancestral primate permanent dentition of 2.1.3.3. The lemur’s environment has influenced their dentition pattern in a few ways. For example, the Indri species use their tooth comb to pry out large seeds from the tough exocarp of beilschmiedia fruits, and the fork-marked lemurs use their relatively long toothcomb to cut through tree bark to induce the flow of tree sap.  

               

Spider Monkeys are found in tropical forest of Central and South America. Spider Monkeys live in the upper layers of the rainforest and typically forage there for nuts, fruits, leaves, bird eggs, and insects. Their diet has contributed to a 2.1.3.3 dentition pattern that consist of large incisors and small molars that reflect the heavy frugivorous diet. Fruit is about 80% of the spider monkey’s diet and because they prefer the fruits of big forest trees that is where they spend most of their time. They can also live for long periods of time on only one or two kinds of fruits and nuts. The spider monkey’s environment has definitely had an impact on its dentition pattern because the available foods in their habitat require the use of small molars to eat.

Baboons are terrestrial (ground dwelling) and are found in open savannah, open woodlands and hills across Africa. Unlike Lemurs and spider monkeys baboons sometimes are carnivorous which makes baboons omnivores. Their diets consist of a wide variety of foods, such as berries, seeds, pods, grass, shoots, twigs, fruits, bulbs, bark, flowers, roots, insects, and a small quantity of meat such as small antelope birds and fish. Their dental formula is 2.1.2.3 which is similar to the human formula but consist of longer canines, most likely adapted to tear through the flesh of animals accompanied by their powerful jaws. The baboon’s environment is highly seasonal, so they had to adapt to the foods available to them at a certain time which is reflected in their diet and tooth comb.

Gibbons are found in tropical and subtropical rainforest from Northeast India to Indonesia and North to Southern China. They can also be found on the islands of Sumatra, Borneo, and Java. Gibbons are brachiaters and rarely dwell on the ground so their diet is limited to the trees. Gibbons love fruit which is the primary source of their diet. The gibbon’s dental formula is 2.1.2.3 which is also similar to humans and apes. They are capable of eating meat with their long canines but prefer less competition for food. Their environment has contributed to their molars becoming bunodont (rounded) from all the soft fruit they eat.

Chimpanzees live in the rainforest, woodland areas and grasslands of Africa. They like to dwell on land as well as the trees which allow them to have a variety of food at their disposal. Chimps like to eat fruits, plants, insects, eggs and meat but there are hundreds of known foods that they eat. The dental formula that allows chimpanzees to eat all sorts of food is 2.1.2.3, which is similar to the dental pattern of gibbon’s baboons and humans. Unlike other nonhuman primates chimps are very intelligent and prefer to use tools to open tough shells of nuts and this strategy definitely has shaped their dental pattern throughout history. Because chimps are land dwellers and eat many kinds of things their environment their level of competition for food is very low, but if they have to compete their large canines would work as a good defense mechanism.

What I noticed is that the primate’s dentition patterns were all influenced by the unique environment that they habituated. The primates that were more arboreal had smaller canines than the more terrestrial ones. Also mostly all the primates had a similar molars because most of their diets were similar with the exception of those who were carnivorous.