Week 4 Comparative Primate Blog Post

Lemurs:

Madagascar and the tiny Comoro Islands provide the world’s only present day native habitat to lemurs, where they do not have to contend with competition from the more advanced non-human primates.

Most lemurs are arboreal; they tend to spend most of their time in the trees and bushes. Only the Ringtail lemur spends most of its time on the ground.

Body size varies greatly within lemurs, there are over 100 species, but they are typically monomorphic in body weight and size. It can be very difficult to tell the difference between males and females.

 Most lemur species lack sexual dimorphism. When there is, the female is usually larger. Their social structure and interaction are female dominated which is different from other primates. Some of the theories as to why there is little sexual dimorphism suggest that environment played a role due to the extinction of predatory birds.

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Spider Monkey:

Spider monkeys, like lemurs, are arboreal. They thrive in the upper canopy of the tropical forests from southern Mexico to Brazil.  Their societies are sex segregated where males are dominant to females. The males are more aggressive and more socially cohesive than females. They are also more territorial. 

They range from 18 to 25 inches in height and from 10 to 19 pounds in weight. Due to the relative absence of sexual dimorphism, males and females are roughly the same size.

Baboon:

Baboons are found in almost every habitat across Africa. They are extremely adaptable animals. They prefer semi arid habitats like the savannas, but some live in tropical forests. They require good water sources and safe sleeping places either in tall trees or on cliff faces.

In all baboon species there is pronounced sexual dimorphism, usually in size but also sometimes in color or canine development. Male baboons body mass is up to twice that of the females. There are also obvious differences in facial features such as the rostrum surrounding the upper canines.

In a species where males face a lot of competition for access to mates, larger body size is one trait that can offer a selective advantage. Sexual dimorphism is a result of mating pressure.

Gibbon:

Gibbons are small sized apes that live in the dense jungles and tropical rain forests across Southeast Asia. They spend most of their time in the trees. There is plenty of food in the trees for them and are a safe distance from predators.

Most adults are small and light weight in size, around 3 feet tall and between 13 to 20 pounds in weight. Males are slightly larger than females. Gibbons have little sexual dimorphism in body size with the exception to the siamang’s species.

Gibbons are the only ape that is monogamous in their mating patters and form a nuclear family group.

Chimpanzee:

Chimpanzees are found across a west-east belt in Africa. Their range spans 22 countries. They live in a wide variety of habitats including dry savannas, evergreen forests, mountain forests, swamp forests and dry woodlands. They are quite adaptable creatures.

Chimpanzees are slightly sexually dimorphic, 

males and females look much the same except the males average weight is 88 to 132 pounds and females average between 70 to 104 pounds. Males and females have an average height of almost 3 feet tall. Both sexes have the same black hair covering their bodies with white beards, pale faces and prominent ears.