Primates: Chapter 6 and 7

Monkeys, lemurs, gorillas, apes and even we humans are part of an order called Primates.  The reason why we are all included on the same order is very simple. We all share similar physical features.

• Primates are generally lively, clever, and very successful at adapting to different environmental opportunities, but comparing to other animals, primates do not offer any physical specialization;
• Primates use hands and feet for grasping;
• Very good vision but not so sharp sense of smell comparing to other animals;
• With a few exceptions, all primates present pentadactylism (five fingers on each hand and five toes on each foot);
• Significantly larger brain than ancestors and other current animals.

AS far as the oldest types of primates ever found, we have Archaic primates dating 65-55.8 MYA, who proliferated in the Eocene and precursors to monkeys and apes are dated to the Oligocene.

During the Eocene Epoch, primates with larger bodies and bigger brains began to appear in the fossil record. and most of the records from that time have some resemblance with prosimians of today. Some other founds suggested that they were spending more time in an erect position than before. By the end of the Eocene Epoch, many of the prosimian species had become extinct, probably due to the cooler temperatures that were starting to change the planet. That gave room for the  appearance of the first monkeys during the transition to the next geologic epoch, the Oligocene

47 million year old Adapidae fossil from Germany (much of the soft
tissue, includingfur, is fossilized)

Since we mentioned the prosimian, let’s take a closer look to what they are.

Prosimian are primates that include galagos, pottos, lemurs, bushbabies, tarsiers and lorises. Most of the animals of this group are located in Madagascar or Asia. Prosimian are more primitives comparing to other primates and some of their characteristics are:

_·         Have a better sense of smell than other primates and usually mark territory with smell;

·         Enhanced night vision;

_·          Most of species are tree-dwelling and that is reflected on their body features;

_·          Prosimians produce a variety of calls to communicate to one another;

_·          Unlike other primates, prosimians reproduce during a distinct breeding season.

Lemurs are an example that is included in the group of STREPSIRHINI, which would be a subordinated division of the Prosimian Primates.

Lemurs are commonly found in Madagascar and some little islands around it. They are divided into 9 genera and 22 species. They can be both diurnal or nocturne, and tend to move slowly during the night, but communicate with each other use sound and sometimes by smell. They eat a variety of fruits, plants and leaves but some of them can eat insects too. 

The mainland version of Lemurs are Lorises, and they can be found in Asia and Africa.

Another subordinated division of Primates is HAPLORHINI. Humans, monkeys, apes and tarsiers and included in that group.

Some characteristics of this division are:

• Wide range of limb movement
• Lack of dietary specialization which is reflected in the teeth
•  Animals in this group have lost the enzyme responsible for manufacturing Vitamin C
• Larger brain and primary sense is vision

Tarsiers.

 

• Small species exclusively found in Asia
• Biochemically more similar to anthropoids
• Eyes are about the same size as their whole brain which makes it difficult to move their eyes, but they are able to rotate their heads 180⁰
• Capability of jumping
• Unique dental formula (lack of toothcomb)

Anthropoids: Monkeys, Apes, and humans

·         Larger brain comparing to body weight

·         Larger bodies

·         Reduced sense of smell and increased sense of vision with forward facing eyes

·         More generalized dentition

·         Females present differences in the internal reproductive anatomy

·         Longer gestation

·         Significant parental care

The monkeys are divided into two different groups:

Platyrrhinii

·         Also known as new world monkey

·         Small, mid- size primates

·         Arboreal

·         Grasping tails

·         Known for the flat noses

·         typically lack the trichromatic vision

 

Catarrhini

·         Old world monkeys

·         Downward noses

·         Never have prehensile tails

·         Have flat toenails and fingernails

·         Generally arboreal, but with exceptions.

HOMINOIDEA – APES AND HUMANS

• Hylobatidae (gibbons, siamangs)
• Pongidae (orangutans, gorillas, chimpanzees, bonobos)      
• Hominidae (humans, and fossil humans)
• Some of them live in trees, but mostly found on the ground
• Developed brains and very intelligent
• No tail
• Arms are longer than legs (only in the apes)
• More complex behavior
• Enhanced Cognitive abilities
• Increased period of infant development and dependency

Gibbon

Gibbons are found in tropical areas with rainforests mostly in Asia, India and Indonesia. Smaller than Great Apes, gibbons present fewer differences between the male and the female sometimes having some characteristics closer to monkeys, but it has evolved  like the apes to lacking tails.

Orangutan

Orangutans are exclusively from Asia living in rainforest areas. They have a large body with prominent mouth area, which allows them to use their mouths for many different purposes. They also present a similar hand to humans, with four long fingers and one thumb. While males are the predominant, the females are very caring  for their new born. Infants are very completely dependent of their mother until approximately 2 years old. 

Gorilla

Gorillas are found in central Africa, but are sadly in danger of extinction. They are the largest of all primates, males can get up to 400 lb. Gorilla’s DNA is very similar to the human DNA.. They are very intelligent and are able to lean new tasks, laugh, show emotions, have a strong bond with the family, divide themselves into groups and some are able to use tools ( For examples a stick to reach for ants under the ground ).

They usually knuckle – walk (uses the help of hands to walk), but something they can also walk on only both feet. The mother is responsible for raising the infant, but sometimes the male introduces the infant socially. 

Chimpanzee

Chimpanzees can be found in West and central Africa, but also are in danger of extinction due to the human population taking over their natural habitat. One of the closest living relatives to the humans, sharing a common ancestor. Chimpanzees also

knuckle – walk, but their feet are better designed for walking than the gorillas, because bottom is broader and toes are shorter. Their behavior is remarkable for having groups where there is a male leader that leads the rest of the troop and they present an omnivorous diet. Interestingly, chimps sleep an average of 9 hours per day. One interesting fact that is typical of the chimps is the grooming, which is an activity based on picking each others hairs looking for bugs and little insects. The average chimp spends about an hour per day grooming another chimp. For them this is a social activity that helps alleviate tension and straighten relations among group members.

Bonobo

Similar to chimpanzees but smaller. Specie is found in central Africa, generally a lot less aggressive maybe do to their sexual active lifestyle. They are capable of feelings such as kindness. Different than most animals, the female has a higher social status and the mother tends to have a connection with son all life. 

 

Primate behavior has some similarities to other animal’s behaviors, but mostly it differs from all the others. I found this very interesting website that presents the different aspects of primate behavior, comparing human with other primates in terms of communication, social organization, and the ability of using tools. 

http://humanorigins.si.edu/evidence/behavior/primate

Among all the different forms of socialization, the mother – son bond is the most remarkable in the primates. This bond is strong because the infant most of the times depends of the mother for feeding, getting around, being introduced to social spaces and others. Most of the times this bond is strong only at the beginning of the infant’s life, but in some cases this bond can last forever.

Another important factor in the social organization is the different forms of dominance. Life I mentioned before, the female is higher socialize in the bonobos. But in most cases males will give up for females, like if for example the female finds the food first.

Sadly, more than 90% of non-human primates  are in danger of extinction, and most of the time that is due to the human actions. At first the main cause was habit loss, but recently that changed to human hunting. 

Primate behavior:

There are two elements to be considered when studying today’s primates behavior: Ecological and Evolutionary.

There is also a new field called behavioral genetics that studies the of certain gene or hormone to the behavior changes, but stream has to be closely analyzed considering the environment  factors that also play a role on the behavior of the species. Considering the evolution of the primates and that each species evolved on its own directions, it is interesting that there are still some similarities on the behavior.

One of the most known characteristics to primate’s behavior is the social grouping. To understand how it became part of the primate behavior it is important to consider how hard it was for ONE individual to adapt to the natural selection changes in the environment, so in order to maximize their survival and reproductive outputs they started organizing themselves in groups. Two important factors could have been the main reason that brought these animals together: predation pressure and the advantage of gaining information from one another.

In early times, these affirmations were hard to conclude without having real life evidence of their behaviors, so one generation after ethology was developed, people started studying primate behavior. Among all the studies that were being developed at the time, the most interesting to me was Jane Goodall who went to Gombe in Tanzania to live with chimpanzees and study their behavior by living in the same environment as them for over 45 years. She is considered the world’s foremost chimpanzee expert.

These early studies allowed for lots of knowledge about how these animals live in social groups.

  

 

Social Organization

1. Single female and her offspring type of family group (Orangutangus and small nocturnal prosimians.
2. Monogamous Family Group which consists in adult male and female with their children - common for humans but not common for non-human primates.
3. Polyandrous family group: The smallest New World monkeys, the marmosets and tamarins, form both monogamous and polyandrous family units.
4. One male, several female type of group. That is to say, one male regularly mates and lives with more than one female at a time, this is the most common organization for non-human primates.
5. Multimale and multifemale groups: The most common social group pattern among semi-terrestrial primates, commonly have a dominance hierarchy among both males and females.
6. A fission-fusion society is one in which the social group size and composition change throughout the year with different activities and situations, commonly found as a pattern for chimpanzees.

Here are some characteristics that would influence such social structures:

·         Body size – males tend to have a larger body

·         Type of diet, could be mostly fruit eaters or small insect eaters

·         Predation

·         Distribution of resources

Personal Input

This was so far the most interesting subject of this class, to me. I am highly interested in understanding the relation between humans and the rest of the primates and understanding their similarities.

What I knew beforehand about primates was very small in content comparing with my knowledge now. For example, I never thought creatures such as tarsiers could be considered primates, but now I understand that in some level, we are share similarities.

It is also interesting to know that despite behavioral and physical similarities, we are all considered primates because of our DNA proximity. To image that for example humans and chimpanzees have only 1.2 percent of genetic difference between them, it is pretty interesting and it makes me wonder, why do we “treat” ourselves like such important species?  Why do we “rule” the world like if any other species would ever be as good? I believe if given the opportunity of learning or maybe the need of adaption necessary to use more of their cognitive brain, probably apes, chimpanzees and so on, would share a very close level of intelligence as us humans.

One sad factor is that most of the non- human primates are in danger due to human actions. It is pretty frustration to me to imagine species that are genetically so close, species that shared the same ancestor between 8 and 6 million years ago, loosing space on Earth to give more space to humans. If instead we all took the time to understand them, like Jane Goodall did, we would see they are closer to us than we can think of, and maybe it would feel wrong to destroy natural habitat or hunt a species that reminds us of ourselves.

Unfortunately we were studying these two chapters, the museums in the DC are were closed so I did not have a chance to go see the primate exhibit, but I did read some very interesting articles and websites during this time of research for this blog post, and I will be sharing the most interesting ones with you.

Additional Information

In the class, we watched a video about KOKO the gorilla, who was trained by Francine Patterson for several years, and learned how to use and understand over a thousand signs based on  the American Sign Language. I loved that video and went on to research a bit more about it. During my research I found a very interesting video about a Bonobo called Kanzi and his sister. They both understand human speech and communicate through lexigrams. This video gives a great background explanation about bonobos, their natural habitat, their fossil records and recent researches about their intellectual capability being very similar to our own.  I decided to share this documentary as a part of my additional information:

http://kanzi.bvu.edu/Kanzi301.html

Following this same aspect that the other primates are able to think similarly to humans, my husband found this video on TED talk, and shared it with me because he knew I was writing this blog post about primates. This video is basically a presentation by Frans de Waal about moral behavior in animals. Waal is a primatologist and ethologist, and in this video he talks about this similar feeling animals share with humans of morality in some specific situations and he presents examples that are mostly in the primates area.
The video is funny, because it compares animal behavior with humans, but at the same time is very interesting to see how the animals behave in situations of unfairness, empathy and compassion. 

http://www.ted.com/talks/frans_de_waal_do_animals_have_morals.html

This next image, I found very interesting, because it presents some of the closest to human primates all standing on a tree and a brief description of each species. 

Lastly, I work as a nanny part time to help pay for my studies, and one of the kids I watch love this book about Chimpanzees from Jane Goodall. I used to always read this book, and I found it very interesting, but before this lecture about primates, I did not really know who the writer was. After this lecture, I actually liked the book even more, because it is a very simple to understand language, but with lots of valuable information about chimpanzees and primates behavior in general and very interesting book for the whole family.  So I decided to add a link to some of her books. I personally loved reading one of them ( The Watcher) and already order some others. 

http://www.barnesandnoble.com/s/?category_id=404907