Chimpanzees (Pan troglodytes) are primates from the hominidae family and are one of the closest DNA related species to humans. It is known that humans and chimps have evolved from great-apes over millions of years. In fact, about 98% of the DNA is shared (Mitani, Watts, Muller 2002). Even with similar DNA, chimpanzees function differently in society than humans do. Through evolution chimpanzees have found various ways to successfully survive. They base their communities off of a hierarchy related with dominance.
Relevant Chemistry
Chimpanzee cortisol levels are directly correlated with their levels of metabolic stress (Muller 2004). Cortisol is a hormone secreted by the adrenal cortex that is signaled by stressful environments such as low food supply. While under high amounts of metabolic stress, it is seen that the chimpanzees lower in rank become more aggressive. This is because during times of food insecurity, chimps of lower rank have to fight the higher ranking chimps for food (Muller 2004). With this information it is shown that aggression in chimps does not decide their rank, dominance does.
Chimpanzee dominance is associated with the expression of different testosterone levels (Anestis 2006). Through observation of chimpanzees, it is found that the Alpha tends to be more aggressive than any other male during times of no stress. This is because rank is based on behavior rather than physical characteristics (Muller 2004). Scientists are able to look at morning urine samples to detect the rank of a chimpanzee. The results at any other point in the day would be inconclusive because the testosterone levels are virtually the same in all male chimps during the day due to an increased amount of males activity and sexual rivalry (Anestis 2006). Due to these results, it is believed that any chimp can be at the top of the social ladder in their community.
By living in communities, chimpanzees are able to survive as a group. Chimpanzees are able to recognize others in their community through the hormones Oxytocin (OT) and Arginine Vasopressin (AVP). These hormones are secreted from the hypothalamus and control social behaviors of chimps as well as social recognition.
They have developed ways of survival and protection such as forming parties to protect their territory from any incoming threat (Mitani et al, 2002). It is extremely rare for these parties to be of only one sex, however the parties are of adult chimpanzees. When it comes to protecting their territory, chimps do not hold back. This is why it is very common for infants and adults to die in territory battles (Mitani, Watts, Muller 2002).
Cell Biology
There are still significant differences between humans and chimpanzees, particularly in the brain. “…the human brain is not only a larger version of the ancestral primate brain but also one filled with distinct and surprising differences” (Neuroscience). Chimpanzee brains are three times smaller than that of a humans. Humans have a gene expression present in the striatum that assists with movement of the body, a gene that chimpanzees do not have. The TH gene, a neurotransmitter necessary for higher-order function is missing in that of a chimpanzee but present in human brains. We can have many of the same genes as that of a chimpanzees, but it depends on how much of the gene the species has to correlate with how much it is used.
Chimpanzees have similar immune systems to that of ours. Both chimps and humans can be infected by AIDs and hepatitis diseases, but chimps can not be infected by malaria contracted from mosquitoes. “A small DNA difference makes human red blood cells vulnerable to this parasite, while chimp blood cells are resistant”(AMNH).
Chimpanzees have been around for centuries. Even dating back as far as eight million years ago. Being around eight million years ago means these chimpanzees have to of had actions, adaptations, and physical traits to help them have survived this long. Through evolution we now have learned how these amazing creatures have been so successful. The Chimpanzee first evolved as early as eighteen million years ago when the first humanoids distanced themselves from the gibbons. These humanoids now are what consisted of Chimpanzees, Orangutans, and Gorillas etc. From separating learning new traits and adaptations these creatures survived through behavioral and physical evolutionary adaptations.
Some of the behavioral adaptations include common the chimpanzee being use the environment they live in to their advantage, they take their resources around them to make & use tools, communicate, protect, strategize, and over come predators (Piel AK. 2018) . These creatures have learned to manipulate tree branches from their territory and shape the tree branch to their needs to catch bugs in crevices, nests, and to even dig for other food sources. They use tools from their environment like rocks to smash against food sources like hard nuts, or to break up food for their young/ to teach them these habits. Chimpanzee’s over time and have had to learn through evolution and updated their mindsets to be where they are today. These animals are also so smart, the way they use the environment they live in to help them excel have also helped them evolve. For example they use leaves from the thick forest trees to soak up, hold, and even cup liquids to drink water.
Since these chimps are in their prime in the trees, this doesn’t stop predators. These organisms have had to overcome an almost extinction elevon million years ago, they have had to outwit their predators to fight for the survival of their species. Chimpanzees have adaption through behavioral traits to make their living situation/ nests in the tops of trees so they can sleep through the night unseen by these predators, this helps to keep their young protected (Pruetz J, Fulton S, Marchant L, Mcgrew W, Schiel M, Waller M. 2008) . During the day they stay in group like communities up to 100 sometimes more chimpanzee’s. This allows them to out number and easily scare away predators.
Behavioral traits are a necessity to help these chimpanzees to survive in the environment of deep forest and thick trees, but physical traits that have helped these organisms to the best of abilities to be successful in the environment they live in. The physical traits include; opposable thumbs, hard soles, facial muscles, strong bodies, and sharp canine like teeth. Similar to us as humans they have four long fingers and one opposable thumbs. This helps the organism have a stronger and better grip on tree branches and tree bark. This helps them move smoother and faster through the trees. Physical adaptations like hard soles, and facial expressions allow them to walk upright like humans, and communicate through facial expressions allowing them to communicate through faces without verbally communicating. They also use these expressions to scare of predators when it’s time and use loud screeches, barks and grunts to ward off, and also communicate (Piel AK. Temporal patterns 2018). Even at night these chimpanzees are a force to be recon with. Besides facial expressions they have chants that they use for each emotion or response to its environment, and or predators. The chimpanzee’s strong bodies allow them to swing from the trees for hours at a time. More specifically their shoulder build, is also known as brachiation. This allows the actual physical makeup of these animals shoulders to help them rotate and use their strength to keep swinging successfully through the vast forests they live in. Lastly these animals sharp canine like teeth. These teeth allow the chimp to tear through their pray like pigs, deer, birds, monkeys, rodents, insects, and latch on with a deathly grip.
Through development of science we now know more about evolution than ever before, with this we now know the following information. Evolution of the common chimpanzee scientific records show the DNA & genetic makeup of this organism is closely linked & shared to the evolution of humans. These shared ancestors, dates back to 8 million years ago. The last shared ancestor of the chimpanzee, and not the human, shared species of the ape and monkey. This ancestor of the shared monkey and ape existed approximately 25 million years ago. Through evolution and the development of science we now know more about evolution than ever.
Chimpanzees mate and reproduces about once every five years, typically giving birth to one baby at a time. A common chimpanzee will have around four to five babies in a lifetime. Chimpanzees reproduce by sexually mating between males and females. Male chimps are capable of reproduction at 16 years old while females are capable at 10 years old. There is no specific mating season but scientist do see a pattern in chimps mating directly tied to food abundance. There is a few ways a female will attract a male. Sometimes during a time of estrus they will mate with multiple males based on opportunity. Male chimps also go through restrictive mating with is when one male will restrict others from mating with the estrus female. Courtship mating is when a male and female leave their community for several days to weeks. There’s also extra-group mating which is when females leave the community to mate with several males from nearby communities. Females will typically mate with several males over a ten day period of tumescence and typically do not mate with a male chimpanzee in the same social group because it could risk the mother and infants acceptance into the community (Lang, 2006). Chimps birth very similarly to humans as the baby comes out rear facing, much like a human baby (Milton, 2011). Juvenile chimpanzees have a very close relationship to the mother while the father isn’t typically involved and will even kill offspring that aren’t their own (Lang, 2006).
Chimpanzees have evolved, adapted, and learned how to survive in the most suitable environments.