Body size and Sexual Dimorphism of Lemur, Spider Monkey, Baboon, Gibbon, and Chimpanzee

Body size and Sexual Dimorphism of Lemur, Spider Monkey, Baboon, Gibbon, and Chimpanzee

Lemurs

A.   Lemurs are only located on the southeast coast of Africa on the islands of Madagascar and Comoro. Lemurs can live in a variety of habitats such as the tropics, desert, and more as opposed to only one region. Lemurs are more commonly located in overgrown forest because they are rich in food supply such as a variety of nuts and fruits.

B.    Lemurs do not have sexual dimorphism based on size, although they do posses other variances, which are more common among one sex. For example, the male's ante brachial gland is larger and thus more visible. Also, similar to humans, the male scrotum is more clearly visible for easy identification of male characteristics.

C.    Lemurs are arboreal, meaning Lemurs are able to move quickly and virtually invisibly throughout the forest. They have adapted to living high up, avoiding most predators. Lemurs have small bodies, which support them in their skills to move quickly as well as hide in congested locations.

D.    

Spider Monkey

A.    Spider monkeys live in the tropical forests of Central and South America. Similar to Lemurs, Spider Monkeys are arboreal. Spider monkeys have tails, which allow them to grasp and swing from branch to branch without opposable thumbs. Spider Monkeys are social and gather in groups of 20 to 30. Although at night, they separate into smaller groups. Spider monkeys locate their foods from the tops of trees.  They eat nuts, fruits, bird eggs, and spiders. They are vocal and are able to communicate through a variety of sounds.

B.    Spider Monkeys have sexual dimorphism in their size. Males are slightly larger than female Spider Monkeys. Due to males’ larger size, they usually weigh a bit more than their female counterpart. The male Spider Monkeys usually gather in small groups with other males, the females usually are alone or with their young.

C.   Spider Monkeys are small in stature, which allows them to quickly and quietly move from tree to tree. Spider Monkeys are very strong and have a tail, which allows them to grasp branches in the trees staying away from their predators.

D.    

Baboon

a.     Baboons can be located in Africa, Saudi Arabia, and Yemen. There are five different species.  Baboons are one of the largest monkeys to exist.  Males usually weigh 33 to 82 pounds and are 20 to 40 inches tall.  Unlike Lemurs and Spider Monkeys, Baboons do not have a tail.  Baboons are usually located on the ground they can climb trees to eat, sleep, and view possible predators easily.

b.     Male baboons are much larger than female baboons. Male baboons weigh about 40 pounds. Female baboons usually weigh less at approximately 20 pounds. Baboons’ facial size and shape are other examples of sexual dimorphism. The female Baboons' head and face grow slows down earlier than the male Baboon. The male canines have been measured to be almost four times taller than those in female Baboons. The female also has the ability to nurse and groom infants who may not be hers.

c.     Baboons are able to easily climb trees related to their opposable thumbs and fingers. Their size assist them to seek their prey and collect foods they like to eat.

d.      

Gibbon

a.     Gibbons inhabit tropical and subtropical rain forest of Southeast Asia as well as parts of China. They are rarely on the ground and stay primarily in the trees. The do not have tails. They have long arms and have hook shaped hands, which allow them to grasp branches and reach far away branches for movement or to collect food.  They swing from tree to tree up to 35 miles per hour. Gibbons are monogamous and live in family groups only.  They food consist of fruit.  Gibbons weigh approximately nine to 20 pounds.

b.     Gibbons have very slight sexual dimorphisms in size. Although they do not generally have a size difference, they do have differences in fur coloring. The female Gibbon is white cheeked and have cream colored fur with a tiny patch of black on the top of their head and the male gibbon is completely black except for white patches on their cheeks.  When born, Gibbons’ fur is cream colored and changes to black at one year of age.  When they ago more, their fur changes color depending on their sex.

c.     The Gibbons fur color provides a camouflage allowing the mother to hide her offspring, less than one year of age, and protect from predators. Gibbons are able to swing throughout the trees quickly, which allow them to get away from predators.
d.

Chimpanzee

a.     Chimpanzees are located in the rain forest and savannas.  They are arboreal and terrestrial animals.  They spend equal time in trees and on land. The Chimpanzee has very long arms and short legs.  They usually live in large groups.  They are able to walk on their hands/knuckles.  Chimpanzees are able to climb trees and build nests to rest during the daytime. They eat a variety of plants as well as small monkeys or infants of other groups of chimpanzees.

b.     There is sexual dimorphism among chimpanzees regarding their size. Males are slightly larger than females. Male Chimpanzees weigh approximately 100 pounds and are around five feet tall. Female Chimpanzees weigh approximately 80 pounds and have less muscle mass than their male counterparts. Chimpanzees are male dominant and have strong aggression amongst groups.

c.     The considerable size difference of male and female Chimpanzees allows the male to appear more dominant. Chimpanzees are larger than other animals and are usually the predator.

d.    

 

Summary

Many of the primates have minimal sexual dimorphisms related to their size and weight.  This fact is also true with humans as well.  In my research, it appears evolution has created larger sized primates based on their environment and resources.  Each species has developed mechanisms to adapt to their safety from predators.  It also appears the Chimpanzee species is the most evolved and similar to humans.