Year of the Monkey: Monkey, Apes, and Humans: How are we different?

By 04/08/2016February 13th, 2018Education

Monkey, Apes, and Humans: How are we different?

By Breanne Cyr, Primates Incorporated Volunteer

When is the last time you received an email from a primate?  Chances are, it was not long before you started reading this.  That’s because along with monkeys and apes, humans are primates, too (1,2,5).  Although monkeys, apes, and humans differ from one another, as primates, they share many common features that distinguish them from other animals.  What are these differences?  What makes us human?

There are many common features among primates.  For example, primates have eyes that face forward and are close together, creating 3-D vision that is also in color. With this increase in visual capabilities, most primates have evolved small noses and rely less on their sense of smell.  Almost all primates have 10 fingers and 10 toes with nails instead of claws, opposable thumbs or big toes, and tactile finger pads – all characteristics that allow them to grasp and manipulate food or other objects skillfully.  In comparison to other animals of their size, primates have long gestation periods, long childhoods, and live significantly longer.  They also have comparatively large brains (3).

The great apes – chimpanzees, bonobos, gorillas, and orangutans – are closest related to humans.  In fact, we share about 98% of our DNA with chimpanzees and bonobos and are more closely related to them than they are to gorillas or any other primates.  In comparison, humans share 93% of DNA with rhesus monkeys (1).  Humans and apes share all the same bones, though they may differ in shape or size, and they also share the same arrangement of internal organs.  On average, males are 5-10% larger than females and are more muscular.  Unlike most monkeys, neither apes nor humans have an external tail.  We share even more of the same diseases with apes than with monkeys and have several blood type systems in common (2).

How are humans different from apes?  Before Jane Goodall’s discovery that chimpanzees used sticks to fish for termites, many scientists believed that the defining feature of humans was their ability to use tools.  Now, however, we’ve learned that several animals make and use tools, and what makes us distinctly human is a complex mix of physical and psychological factors (6).  Physically, human brains are three times larger than ape brains (5), humans are not covered in thick hair, and our anatomy differs to support bipedalism, or walking on two legs.  For example, in comparison to apes, our legs are relatively long, and our arms are relatively short and weak.  Our feet are proportionately longer and have developed arches. Meanwhile, we have lost the ability to use our feet to grab and manipulate objects effectively as apes do.  In terms of reproduction and offspring, giving birth is much more difficult and risky in humans than in apes because human babies are born comparatively large (2). Human babies are born at a less mature stage to help compensate for this large size (2), but this, along with the fact that human babies are not born with the ability to hold on to their mothers (4), leaves our babies more vulnerable.  Whereas female apes remain capable of giving birth even when they are very old, humans lose this ability when they go through menopause (2).

Cognitively, apes and humans vary as well.  Apes have intelligence levels around that of a three to four-year-old human (2).  Similar to humans, apes can identify other individuals and understand their peers’ relationships to one another.  They perceive and understand the past, present and future. They use reasoning and inference.  Apes learn from each other, but they have a much smaller emphasis, if any, on intentional teaching – an element that is prominent in human culture.  Apes show culture in that certain behaviors and information are transmitted across generations, but they do not depend on it, and it does not evolve the way that human culture does (5).  As a part of human culture, individuals work together to create increasingly complex interactions, ideas, and technologies (2,5).

Despite apes being cognitively intelligent, they lack the extensive verbal communication and the complex social organization demonstrated by humans.  Humans are the only animals to create and use symbols or words to communicate (2,4).  This allows us to communicate and live in complex societies where we understand each other based on mental constructs that we form through language.  While some apes have been taught to communicate using a form of language, humans are the only ones who readily communicate and share in a way that has enabled us to construct civilization (4).

For example, we are able to create cultural entities such as marriage, occupation titles, and political parties that are symbolically understood by society (5). Unlike apes, we live among and communicate extensively with people we don’t know, and we are able to communicate without even being near each other – such as by using the telephone, writing emails, or posting on social media (4). Additionally, our use of illustration and written word allows our communication to span through generations in a way that does not occur with apes (4).

Hence, there are many aspects to consider when comparing monkeys, apes and humans, and the boundaries aren’t always clear.  Many scientists agree that what distinguishes humans from apes most is our ability to use language to form complex functioning in groups, but others believe it is our physical differences, cognition, or culture that sets us apart.  If you can’t remember all the differences between monkeys, apes, and humans, just remember this: Monkeys (almost always) have tails; apes have the human intelligence of a 3-4 year old child; and humans are the only ones who use Facebook to tell you what they had for breakfast!

Sources:

  1. “Genetics.” What does it mean to be human? Smithsonian Institution. April 4, 2016. Retrieved from http://humanorigins.si.edu/evidence/genetics
  1. O’Neil, Dennis. “Humans.” Behavioral Sciences Department, Palomar College. 2012. Retrieved from http://anthro.palomar.edu/primate/prim_8.htm>.
  1. O’Neil, Dennis. “Overview.” Behavioral Sciences Department, Palomar College. 2014. Retrieved from http://anthro.palomar.edu/primate/prim_8.htm
  1. Savage-Rumbaugh, Sue, and Fields, William. “Human Uniqueness–Constructions of Ourselves and Our Sibling Species: Pan troglodytes and Pan paniscus.”Quo Vadis, Behavioural Biology? Past, Present, and Future of an Evolving Science111.380 (2013): 205-226.
  1. Tomasello, Michael, and Esther Herrmann. “Ape and Human Cognition What’s the Difference?.”Current Directions in Psychological Science19.1 (2010): 3-8.
  1. “Tool Use.” About Chimpanzees: Chimp Behaviour. Jane Goodall Institute of Canada. Retrieved from http://www.janegoodall.ca/about-chimp-behaviour-tool-use.php