Dentition Patterns

Lemurs are only found on the African island of Madagascar. Madagascar is roughly the size of Texas, and is home to approximately 250,000 species. The forest trees of Madagascar are often large and not straight. The branches are covered with epiphytes, mosses, and lichens. . Lemurs adapted to living and feeding off of trees, when separated during early primate evolution. They evolved to an arboreal lifestyle. They don’t have much competition for food. Their diet consist mostly of fruit, leaves, tree bark, and sap. Lemur’s teeth are comprised of long, curved incisor teeth; they have 8 incisors (2 in each quadrant of the mouth). Lemurs have incisors, canines, premolars, and molars in the upper and lower jaws. Their premolars are canine – like. Their dental formula is 2.1.3.3. They have reduced incisors and tooth comb, as compared to spider monkeys.

Spider monkeys inhabit Central America, South America, and Mexico. All three regions have tropical environments. South America has area of approximately 17,840,000 square kilometers. It borders the Pacific Ocean on the west, and the Atlantic Ocean on the north and east. It is also home to the Amazon Rainforest. Spider monkeys differ from Prosimians, in regard to their jaw and teeth. They have 2 incisors, one canine, 3 pre molars, and 3 molars. They have no hypoconulids on the first 2 lower molars. A dental formula is used to describe the number of each type of tooth that specifies a certain species. The dental formula for a spider monkey is 2.1.3.3.  Their teeth evolved to adapt to their arboreal living. Spider monkeys stay near the tops of canopy trees. The trees serve as a defense from predators below. This explains why their diets consist mostly of fruit, bird eggs, insects, and seeds.

Baboons live in Africa, just as lemurs do, and prefer a semi – arid habitat. Africa’s climate ranges from tropic to subarctic. The northern half is arid, while the southern and central areas contain dense rain forest and savanna plains. They eat fruits, grasses, roots, bark, and seeds. Baboons also eat rodents, birds and other meats. They have broad incisors, molars with high crowns, and low cusps. Baboons have powerful jaws, as well as long teeth. This trait helps to defend against predators, as well as compete for food. Their dental formula is 2.1.2.3, much different from that of spider monkeys.

Southeast Asia is home to gibbons. The climate is warm, humid, and could be generally characterized as monsoonal. The trees of the region are tropical, and are abundant in fruit. Gibbons spend most of their time in trees and feed on fruit trees. They specifically enjoy eating figs, but also eat tree bark and leaves. Gibbon’s dental formula is 2.1.2.3, just as the baboons are. Gibbons have shortened jaws with long canine teeth. Their teeth also resemble that of great apes.

Chimpanzees inhabit both tropical forest and bordering savannas in Africa. The savannas have scattered trees with an arid climate. They consume ripe fruit and young leaves. Chimpanzees have 32 teeth; 16 on upper jaw and 16 on bottom jaw. They use their molars to grind fruits and leaves. Their dental formula is 2.1.2.3, just as gibbons and baboons are.

Animals that have a plant based diet, tend to have more molars. They are needed to crush and grind leaves. They tend to be less aggressive, and their dental formula is typically 2.1.3.3. Examples of these animals are lemurs and spider monkeys. They live in tropical rain forest and inhabit trees. Their plant based diet is abundant in their habitat. However, animals that have a meat based diet, tend to have larger incisors and less molars. Their dental formula is 2.1.2.3. Examples of these animals are chimpanzees, baboons and gibbons. They are more aggressive because they must compete with carnivorous animals. Chimpanzees use their teeth to explain emotion. They smile when relaxed, but when frightened, use their teeth to intimidate threats.