The Evolution of Primate Intelligence

The intelligence of the primates is more advanced compared to other animals based on behavioral complexity. The primates are cognitively advanced as compared to other mammals in the society based on their capability for cognitive awareness and also the ability grows importantly from prosimians to the humans. The researchers have provided the parameters to define and compare intelligence based on the causal factors resulting in the cognitive growth. In the study of how the primates evolved the scientists have been faced with problems to determine the intelligence that no longer in existence (Dunbar, Robin and Susanne 650). Though as humans we are not descended from the modern-kind ape or monkey, the lineage appears to be going through stages where we were a medium-sized, the hands that were good at modification, the capability to climb trees and also the reason as intelligent creatures with efficient vision. The evolutionary trend in the primates involves growth and development of offspring after and before birth and the modification to a complex social system. The paper provides the trends in the primate evolution to a more and advanced brain in relation to brain size, gestation period and the social organization.

The size of the Brain

It is evident that the larger the brain the more intelligent the species. Therefore, considering primate evolution size of the primate brain has grown in terms of size. In relation to morphology and brain size, most of the mammals show some aspect of asymmetry based on the right and left part of their brains. According to De Waal & Frans, the mammals are divided into two major groups such as Ineducabilia and Educabilia. The Educabilia is a group with a brain surface that has to be reflective to some level of intelligence such as Bonaparte. Bonaparte’s Educabilia is like carnivores, manatees, ungulates, whales and primates. They are characterized by having a large portion of the brain, cerebrum divided further by crease of fissure into various segments.  On the other hand, the Ineducabilia is the inferior group within the similar context. The group is featured to have single-lobed and perhaps an undifferentiated cerebrum.

Moreover, the hominoids not only have large brains, their brains are different from those of other primates who are having a more distinctly asymmetric based on the right and left cerebral hemispheres in relation to features are not equal in terms of size or perhaps the extent of expression. According to research, humans have been identified to have grown and developed more advanced cerebral asymmetries which are expected to be correlated to the aspect of language and handedness of information from various senses. The size of anthropoids’ brain is larger that is relative to the weight of the body compared to that of prosimians and featured by a complicated pattern of the folds present on the surface. 

Consequently, the neocortex that has the role of receiving, synthesizing and analyzing is the brain regions that have recently evolved to a greater extent. This is expressed through the clever stuff such as learning, sense making and language of the world. It has also taken up about 85% of the human brain compared to less than 60% of a modern world’s monkey’s brain. The humans have long been identified to have developed extreme cerebral asymmetries which are supposed to correlate with a language and handedness. The scholars believe that the factors reflect an adaptation for staying with a larger group with a more sophisticated social interaction.

Gestation and development period

The reproductive system based on copulation, gestation, birth and lactation takes place in the higher female primates for a period of a year or more than a year. It is evident that the female does copulate again up to a point where the previous offspring have weaned fully. The primate’s infants are born having a fully furred and with their eyes wide open having capability to see and identify things. After the birth period, the infants begin on a journey that is accompanied by a long period of growth and development in care that is extended to the other family members and social group and not only from the mother. The stability and complexity of the societies of the primates provide a high system of protection that allows the infant to have a long duration of learning.

Consequently, this is different from the case of man, gorilla and chimpanzee where the newborns are able to hold their mother’s furs without any support. In this group, the physical dependency which ends when the infants are weaned but are proceeded by an extended time frame of maternal dependency for a period between two and half years in the lemurs while about fourteen years and above in humans. The education time frame is important for the animals that specialize in complicated reactions to immediate situations other than in some kinds of patterns of behavior.  The dependency period acts as a point for learning abilities and getting more attention from the parents. The role of the time is to pass skills that are necessary for the development of capabilities.

The gestation periods for the primates are significantly long allowing them to develop more in relation to the complex brain. For a more mental development for infants, there is a requirement for a more time to be exhibited from a more sophisticated species during the development stages. The primates always have a strong bond between mother to infant and perhaps a longer childhood development compared to other animals (De Waal & Frans 345). The bond allows the child to learn more from the parent’s skills such as hunting and other ways of getting food. Therefore, it is imperative that most of the primates bonding system enable the infants to become strong in terms protection and other relevant developmental aspects. It is during this time that an infant has a chance to learn from the mother things that are significant for survival in the environment at a later stage of their lives. Therefore, this process is better compared to other animals that allow the infants to learn on their own due to early separation.

 The primates learn a number of life skills within their environments. These are things like what to eat, how to each a variety of foods, where to get food, mating rituals, females also learn maternal aspects and social structures. These allow for the primates to develop and survive within the environment. The primate’s development starts in the maternal uterus where the brain begins to grow. It is then imperative that the longer the period of gestation the larger is the size of the infant’s brain. The longer gestation period allows enough time for the development of the brain. It is also assumed that the more the time is spent in the childhood and infancy the more the animals find time to learn relevant skills within its environment. Therefore, there is always a correlation in factors such as the length of a gestation period, infancy and development and also the lifespan in the primates. They all have an importance in the life of primates. Because of a higher of intelligence, the various types of primates engage in a number of complex social groups. The groups of primates are monogamous, polygynous and various multi-male and multi-female groups (De Waal & Frans 349).

The social organization of the Primates

The monogamous system

This consist of a single male and a single female who have joined together in order to raise a given family. One example of the monogamous system is the gibbons. There are few opportunities to establish a relationship besides one with the mates and also lack complexity in picking who to mate with and also who to spend their lives with. Therefore, people have done experiments and have been shown that monogamous animals when given chance enabling them to choose their partners to associate with in the long run. The primates that are in monogamous societies shows a variety of features like the absence of sexual dimorphism in relation to coloration and size, a highly improved territorial in all the sexes, the absence of given defense against the predators by the adult’s males and also closely fashioned operations by both adults and females. 

The Multi male and multi female system

In the non-human primates, the communities of chimpanzees appear to be the most complex of all with the male alliances and individualistic female system. The common chimpanzee is a good example a multi-male and multi female system where a group of animals having various adult males’ adult females are reproductively mature (Herrmann 1364). Females in the multi-male, the female system are solitary within the chimp since they haven’t learnt as much and don’t have much contact out of gestation period. Moreover, a commonly known chimpanzee has a specific type of social organization where people constantly establish small subgroups but from every time also combine together in the larger group. The difference in the group depends on the type of food and also the group where one time could be of the following types such as adult females, all females, one female and also offspring. This kind of animals has a specific mating system that is described as promiscuous.

 The leader of a chimpanzee community is the male whose role is to protect the members of the group and also to hunt. There is an overall dominance list amongst the male groups. According to Research, the males always begin to interact with the other counterparts males in the community when they become older based on the established by a hierarchy of the adulthood. The association between the males are the strongest with a good grooming and food sharing taking place between the males in that specific society. Therefore, in the male group leadership, the highest ranking people within the dominant group commonly known as the alpha status is obtained by forming a coalition with an older non-relative or sometimes a brother. The leadership of the alpha male is known across the society and he decides everything that involves the relative and relationship management. The coalition between the alpha male and either the brother or a non-relative allows for the group to protect the clan from their enemies that might bring issues of attacks and other social problems (Moynihan 213).

The primates have developed the capability to the individuals as tools manipulating the social environment in order to pre-determine objectives as an important factor in the evolution of the primate’s intelligence. One of the ways primates use to manipulate relationships is through alliance formation. The maintenance needs an animal to analyze an important amount of information such as relationships between individuals involved in the alliances together with their relationship to other individuals. Most of the animals form alliances against individuals the primates establishes an intra-group alliance which takes the form of mutualistic or protective support. The intra-group interactions allow for the manipulation of the support system which corresponds to desirability as an ally such as solicitation, reciprocation and also friendships (Herrmann 1362). The advancement of their intelligence has been particularly important to the species in the group. Most of the species live in the social groups that have a rather authoritarian internal arrangement in conjunction with a bluff, violence and other conveniences in order to settle disputes. 

The primates like the apes and the chimpanzee who are the closest relative to humans have heard their intelligence tested by humans for decades. In the present society, they are actually painting, they have learnt how to speak some few words, they have also received instructions in the sign language for the purposes of communications and also an attempt to coach them count objects. The humans are not only the primates who have a quick thinking and learning of objects, bluff and the political maneuvering. The learning capabilities also have a variety of evolutionary status where the possibility of status. The primates have been taught on how to learn and read as an aspect of elevation strategies. Basically, the primates indicated the ability to develop cognitively and analyze the situations both inside and outside the environment (Herrmann 1360).

The Polygynous system

The Gorilla belongs the class of Polygynous system where every male to mate with two or more than two females. The females don’t relate to one another and thus have little to provide to each other socially. The males are responsible for protecting the females from the outside males who might harm them physically (Reader, Simon Yfke and Kevin 97). The layer of protection is established by a group of males who are responsible for protecting. The long bonds form between the dominant male and the females. It is also evident that the females submit to the males and take the responsibility of staying more around the males in order to maintain the level of proximity. Moreover, the second level of the males tend to hang around with the females more than other females but their proximities are the responsibility of the subordinate males and not of the females his hanging out with.

Additionally, the primates that live in the polygynous groups typically indicates the various characteristics such as a bonded adult females, a social reproductive males, a strong tolerance by a reproductive or potentially reproductive males, leadership are shown by some females in most aspects of a group life, while the adult males demonstrate an outward to establish a group orientation (Reader, Simon Yfke and Kevin 256). The group has a clear understanding of what is important for the development of strong ties and a larger extent of the community. The ability to maintain such an understanding allows for the group to stay together based on a clear extent of understanding. The polygynous system establishes a community system for the development of what is known as the greater part of learning one another based on the likes and dislikes. This is important for the creation a strong and solitary family that is embedded with a greater influence of power.

The tarsiers of the south

 They are among the smallest living primates in the south of Asia. The tarsiers were considered true prosimians but they are currently placed on a different radiation resulting to the Lemurs. Though they are nocturnal, they share a variety of traits with the anthropoids like the dry nose and also the absence of a tapetum and another kind of layer to the retina located in the eye. On the other hand, they also have specialized features such as the eyes being larger than its brain in terms of size. The size of the brain is about 3CC compared to the human brain which is about 1400CC (Reader, Simon Yfke and Kevin 567).

The tarsier in the category of nocturnal is known as the arboreal that spend their whole life on the trees. They move by leaping from one tree to another tress and also sleep on the trees. They hope on the land rather than walk. The tarsier is carnivores; eat insects, lizards, and the very little animals. They don’t look for food but sit and wait for the prey. Moreover, similar to lemur they mark their territory for the development of the lives. Studies also show that their social behavior is distinct from the other animals. They often live in individual territories that overlap with the males the family groups with mated pair and offspring especially the larger polygynous group system. Most of the groups sleep together while in other regions the males and females have different and separate territories. The tarsiers have long six months gestation periods with the least fetal growth among the other animals. The infants suckle for two months as they learn how to catch their prey.


The primates’ intelligence has evolved throughout the extension of life. They have grown through various ways in relation to the how they live socially, what they eat and perhaps how they take care of their young all the way from gestation period. It is evident that their intelligence has constantly improved with time as they become more caring and develop various methods of family issues. Based on social intelligence, the group living is considered to be the force that is behind there evolution of behavior complexity and also intelligence. It is evident that most of these animals have a structured family tie that enables them to protect their families. Moreover, it is also vivid that some of the primates have shown some level of intelligence through various aspects such as learning signs and also becoming friendly. The evolution has also been witnessed through their hunting of prey skills and also taking care of their young ones. The young ones after some time of weaning, they have to begin staying seeking the knowledge about the environment to enable them to become effective in the group.


Dunbar, Robin IM, and Susanne Shultz. “Understanding primate brain evolution.” Philosophical Transactions of the Royal Society B: Biological Sciences 362.1480 (2007): 649-658.

De Waal, Frans BM, ed. Tree of origin: What primate behaviour can tell us about human social evolution. Harvard University Press, 2009.

Herrmann, Esther, et al. “Humans have evolved specialized skills of social cognition: The cultural intelligence hypothesis.” science 317.5843 (2007): 1360-1366.

Moynihan, Martin. The New World primates: Adaptive radiation and the evolution of social behaviour, languages, and intelligence. Princeton University Press, 2015.

Reader, Simon M., Yfke Hager, and Kevin N. Laland. “The evolution of primate general and cultural intelligence.” Philosophical Transactions of the Royal Society B: Biological Sciences 366.1567 (2011): 1017-1027.

Leave a Reply