In a world where time travel is not possible there is no way to observe evolution directly as each species changes and diversifies . In order to better understand the process and its effect on species we must observe them and their ancestors , by observing we can find similarities between these animals as well as the differences and how each one has adapted differently to its own environment.
By observing Chimpanzees and the Crested Capuchin monkey, both of which had an infant and mother pair it was easy to see the differences as well as the similarities between the two very different groups in how they interact socially , how they care for their infants and feed . These two groups shared similarities with human behavior as well, actions that were witnessed in some cases were very human especially with the chimpanzees.
Observing these behaviors as well as primate culture allows us to grasp a better understanding of where we as a species came from, although we did not descend from primates we do share a lot of similarities with the great apes such as bone structure, the capacity for learning, and behavior. The Chimpanzee (pan troglodytes) are closer to humans genetically then the other members within the superfamily Hominoidea, they belong to the subfamily Pongidea which also includes gorillas and orangutans and their species is classified as Pan.
They reside in Africa where they live in multiple habitats ranging from the rain forest to grass lands and dry wooded areas, different groups in different areas eat and behave slightly different than others. These apes spend about 1/3 of their time on the ground making them semi terrestrial and use a modified version of quadrupedalism known as “knuckle walking” or quad. Chimpanzees are known for their use of tools in every day life, the use leaf sponges with dew on them to drink water and also wipe themselves, long sticks in a process referred to as termite fishing and they also create sharp sticks for hunting.
They rely mostly on fruit leaves and insects as part of their diet but will supplement meat in, they hunt and kill smaller mammals one in particular being the colobus monkey for food and are the only primate known to do this. These apes are also very social, they like to live in large social units where the members are always changing as they sometimes migrate between groups. Family bonds between females is very strong with this particular ape, mothers and aughters will often stay in the same group or move together. Behavior is not inherited for these animals it is learned and therefore playtime is used to teach young the culture of the group. The Crested Capuchin Monkey (cebus nigritus) reside in the Atlantic forest in Brazil , unlike the chimpanzees these monkeys are strictly arboreal and are full quadrupeds , they have a prehensile tail they use for helping them along the canopy, the tail can act like fifth limb it allows them to grasp branches and balance.
These new world monkeys are part of the superfamily Ceboidea and the family Cebidae and are part of the subfamily Cebinae, they have a very distinct nose called a platyrrhine nose where the nostrils are usually separated by a septum and open facing forward it is a characteristic of New World Monkeys. Much like the chimpanzees these monkeys have developed a way of using tools to open food or aid in the process of feeding, they use rocks to smash hard nuts and seeds open, those in captivity have been seen using sticks to fish for ants.
These monkeys are omnivorous and will eat both vegetation and insects as well as small vertebrates. They are social and live in troops of 5-20 each troop contains a dominant male and a dominant female and can have multiple males , though the dominant male is most likely to mate and father the young, they do not mate in set pairs as they are polygamous .
While observing these animals in captivity there was some likeness in behavior but certain situations were very different. Both groups had infants that a mother was carrying. The mother chimpanzee carried her baby on her stomach, the infant held on to the mothers hair and hung below her, the capuchin mother however carrier her infant on her back its tail intertwined with hers and it rested its head against her neck and gripped her sides with its fingers.
Very rarely did the way the mother capuchin monkey change the way it held it’s young, however the mother chimpanzee when immobile would cradle the infant in it’s arms its head resting on its elbow for support and its hand under the infants rear, the chimpanzee mother sometimes implemented a rocking motion as she sat with the infant much like we do with our own babies. When it was time for both infants to feed each mother handled the situation a little differently as each infant was in a different stage of eeding. The chimpanzee infant was still taking milk from mom, it indicated it was in need of food by pulling on the mothers chest and trying to pull itself to the mothers breast eventually mom would support it and lift it to where it needed to go allowing the infant to feed, where as the young capuchin monkey was perched on moms back while she chewed a nut or a piece of fruit then handed small pieces that it could then place in its mouth and chew.
Both groups acted very differently around mom and infant as well, the chimpanzee enclosure contained six females and one infant, three of the other females were pregnant and two appeared to be in esterus as their backside was very pink and swollen . There was a set group of four females that included the mother chimpanzee that stayed very close together, the mother was constantly paired with one other female who a docent informed me was her own daughter.
This group of four surrounded mom on occasion when wind picked up as it was raining and cold the day I went and would take turns holding the infant for mom, the daughter of the current mother sat next to her at all times and occasionally held the infants hand or covered its head from the rain with her arm. This group was very protective over the infant as the other two who were not part of the related family group were not allowed near the infant , two females would chase them off if they got to close to mom or whoever was carrying the infant at the time and smack the ground .
The infant itself had gestures very similar to human children, when it was with another chimpanzee for a long period of time it would stretch its arms out in the direction of its mother and pulse its hands in and out of a fist to get her attention and continue to do this till she came and picked it up. When the mother was not mobile and it as perched against her chest it would fidget and pound on her chest or explore its moms face with its hands. The chimpanzees were very interactive with the infant, the capuchins however were not. The capuchins were in a mixed enclosure it contained five females and four males and the one infant.
It was feeding time and all of the monkeys were separated from each other and protecting their food, unlike the chimpanzees who sat in a group even while eating. They stole food from the infant and the mother and seemed to pick on the mother as she was an easy target carrying the infant on her back making her easier to take food from. Mom was the only one that carried the infant and unlike the chimpanzee infant the capuchin infant could leave its mothers back and climb and walk on its own for short periods of time though she stayed near it and defended it from the others while it fed.
This group was not as focused on the mother as much as they were focused on eating and protecting their food. The chimpanzees enclosure was mostly flat grassy land that had a water fall and a system of rocks and a cave for climbing, the four that stayed grouped together stayed on top of the cave/rock system most of the time and sat and groomed each other , one sat behind the mother and picked at her using its thumb and foreigner and placed whatever it found into its mouth while the other pair sat one facing the other the one in front held the others mouth open and it began to pick at its teeth and occasional lick them.
The other two that were isolated from the main group walked using the apes modified form of quadrupedalism termed “knuckle walking” where the knuckles are placed on the floor in front of the animal and pressure is applied and used as leverage to push off , this is why apes such as chimps have longer arms then hind limbs, they often held hands as they moved through the enclosure.
One of the two isolated chimps became very curious about the baby and as it moved towards the mother the other of the two quickly moved towards her and put its hand on her back and began to shove her forward and away from the situation she then took the others hand and guided her to the other side of the enclosure. The chimpanzees when not mobile sat down legs bent in a couched position with arms folded in front much like we do when we are at rest. The capuchins were feeding as stated before during my visit, their enclosure was a system of branches that was surrounded by dirt , they only came down when they needed to grab food.
One of the capuchins used a rock to open the walnut it was eating while others smashed there’s against the side of the enclosure. A common occurrence after getting the nut open was dipping it in the pond they had, one did it a few times then a few others started to follow, the chimps just ate what they had no washing or cleaning of the food was necessary. These monkeys also walked like true quadrupeds placing one limb in front of the other while their tales would occasionally wrap around the branch when the branches would become thinner.
A few of them would exhibit bidpedalism for a short amount of time after they grabbed food, they would carry the food cradled in their arms and rush up a branch quickly returning to a quadrupedal stance after setting the food down. They also exhibited semi brachiation as they moved through the enclosure, they would suspend themselves beneath a branch arms not fully extended using a hook grip to grasp the branch and swing or drop down to the next branch. They were very scattered and not as socially active as the chimpanzees were.
As well as being very different in behavior both were very different in appearance and size. The chimpanzees arms were slightly longer than its legs and torso, and had black hair, some of the older females had begun to lose their hair and had bald spots in places so their grey skin was evident underneath. Their faces were greyish black in color except for the infant the infant had a flesh toned face and hands. Each chimpanzee was very different from the other not only in size but facially no two were the same it was easy to tell them apart from each other.
The group ranged in size but all seemed to be around the three foot range when standing. The capuchins were a dark chocolate brown with long prehensile tails, were the chimpanzee had no tail. None of them were losing hair and though they varied slightly in coloring they were very similar facially, they had noses that opened forward(this is known as a platyrrhine nose which is a characteristic of new world monkeys) where the chimpanzee had nostrils that faced down which resembled a human nose.
Their faces in contrast to the chimps was very pale in and fleshy, their eyes were set a little closer together than the chimps as well. The capuchins did not resemble humans The capuchins acted very primitive in comparison to the chimpanzees, the chimpanzees actions were very similar to that of a humans and in some cases reflected actions that were going on outside of the enclosure.
As stated before the infant would reach for its mother , toddlers and babies in the area were doing much the same thing as another member of the group they were traveling with picked them up, or they were confined to their strollers for to long the difference between the two was that the human infants and or toddlers would scream or cry if the situation was not remedied soon the chimpanzee infant stayed quiet and just reacted with movement. Some humans carried their infants in carriers that were strapped to their chest imicking the way the chimpanzees carried their offspring, while other humans had them strapped to their back which mirrored that of the capuchin. The other commonality between chimpanzees and humans was the constant affection and contact with their young, humans carried their young close to them or held their hands as they strolled through the zoo, which is a behavior that was exhibited by the chimpanzees. Couples walking around the zoo held hands as well and though the chimpanzees within the enclosure were not a couple the two that were isolated did walk the enclosure like that most of the time.
Human behavior was very close to that of the chimps but very little the capuchins did mirrored human interactions or behavior. Though they did use tools to eat their food and washed it which is a human habit as well, those that were sitting around the enclosure rubbed apples with their clothes are a towel before eating them and younger ones much like the capuchins were not inclined to share and would run away or hide the food they were eating if approached by another human.
The capuchins did exactly the same thing when approached by another monkey within the enclosure. Due to the weather it was hard to get a big group and good sample of human activity as there was very little in the morning due to rain the day of observation. Both species shared human like qualities and by observing them closely and for a long period of time it was easier to see the traits that they had adapted in order to better suit their environment.
It was also easy to see the behaviors and actions that we as a species share with are closest relatives. It was also interesting to see the major contrast between these two groups both in appearance and actions, though they both seemed to carry a level of intelligence the Chimpanzees exhibited a much more complex array of behaviors then the capuchins did. By observing these animals I was able to see aspects of evolution at work and how three very similar species could diverge from each other so much.