Table of Contents
What is the cause of primate social behaviour?
Caring for one’s appearance
Share Food
Altruism in Other Forms
In conclusion,
What is the cause of primate social behaviour?
According to American zoologist Edward Wilson the evolution of social behavior is responsible for primates’ social behavior (Larsen. 194). The primates are able to show both aggression and kindness, even though these two elements have opposing meanings. What evolutionary factors are responsible for the presence of these two contradictory characteristics in primates today, including humans? This paper aims to examine the existence of altruism in non-human and human primates, and understand why it’s considered important for evolution.
Richard Dawkins (ca. 1976) explained in the selfish-gene theory that human evolution was due to selfish genes. He believes we evolved because of the desire for survival and reproduction in our genes. Time has shown, however, that humans have always cared about others and displayed altruistic behaviors (Slyke 2010). Altruism has been defined as the act of doing something for someone else at the expense or the actor performing it (de Waal, 2008).
Altruism can be seen in all humans, including strangers. Even when there are no obvious benefits, people will act altruistically. Reciprocal generosity is when you help someone who helped you before (Slyke 2010, for example). Indirect Reciprocity is when someone helps you without any direct benefits. You will gain a better reputation and increase your chances for receiving benefits later on (Slyke).
Humans can also act altruistically out of concern or empathy for the receiver (Silk & House 2011, 2011). Altruistic acts can also be motivated by selfish motivations where the actor expects to reap benefits in the future (Silk & House 2011, for example). In a 2007 study, participants were encouraged to show off their generosity in order to get selected as a partner.
It is important to note that kin selection also occurs in altruism, as humans tend to be more generous with family members (Slyke 2010, 2010). As you can tell, humans display altruism for many reasons. They can do so for a number of different reasons. These include gaining reputation or understanding someone’s need for assistance. How important are these mechanisms to the evolution of humans?
A study on altruism found that altruism towards non-relatives is a sexually selected trait in humans. People look for this trait when choosing a partner (Phillips Barnard Ferguson & Reader 2008). This reinforces the notion that the altruistic trait is an important component of sexual evolution. Altruism may be important to the evolution of humans.
Altruistic acts are performed by many humans every day. They may open a door for someone, or allow them to go ahead in the grocery line. Small acts of kindness may not be enough to increase our chances of surviving, but larger ones may. A person could give money to someone in need. Money can be used to buy food for the person, as it is essential to their survival. The act of giving money, or any other similar act, allows someone to live and perhaps reproduce. This would be a contribution to our evolution. Altruism is also a way to increase social bonds. This can be viewed as a key component in survival.
Non-human primates also exhibit altruism. In my research I’ve noticed that non-human primates and humans both perform altruism. There are also some differences. In nonhuman primates altruism is expressed in many ways, including grooming, food-sharing, and various other situations.
GroomingAllogrooming, or social grooming, is perhaps the most common altruistic behavior performed among primates (Schino & Aureli, 2010). One possible reason for primate grooming is kin selection. Primates may groom their relatives (Schino and Aureli, 2008). Rhesus, Japanese and other macaques groom their closest relatives more than distant ones (Silk (2002). Another explanation is reciprocal altruism, which is seen in red-fronted rufus lemurs. (Port, Clough, & Kappeler, 2008).
Schino & Aureli (2009) carried out a study in which they found that reciprocation explains more of the grooming distribution than kin-selection. The reciprocation of grooming does not have to be equal. According to Port et.al. (2009), redfronted lémurs’ female primates who were ranked lower in their groups groomed other primate species the most. Port et al. (2009) showed that men gave less to women in average than what they got from them.
What other reasons are there for primate grooming? The purpose of grooming in chimps is to encourage future help from those who are being groomed (Koyama Caws Aureli 2006). Primates, who do not groom in the conventional sense, will also often clean wounds of other primates or conspecifics to help heal the wounds (de Waal). Outcasts will groom in exchange for tolerance at feeding areas, where they won’t be sharing food (Silk 2002).
What is the importance of grooming to evolution? It is similar to humans in that it helps form stronger social bonds. The species can survive by fostering cooperation and preventing future conflict (Koyamaetal.com, 2006). The grooming can also be exchanged for food (Frank & Silk 2009). Additionally, cleaning wounds could ensure that the individual survives and can reproduce. The sharing of food is a prime example of the altruism that primates display.
Food SharingFoodsharing is probably the second-most common form of altruism in the primate population (Silk et al., Brosnan et al., Henrich et a., Lambeth and Shapiro (2013). Jaeggi&van Schaik (2011: chimpanzees in the Wild are the Only Nonhuman Primates to Share Food). Silk & House (2011, p. 61) found that capuchins, marmosets and tamarins share food more than chimpanzees. When I was observing the Ellen Trout Lufkin Zoo for field work, I saw that two white-faced Sakis (Pithecia Pithecia), shared food.
As I do not have any knowledge of the monkeys’ relationship, I cannot determine the reason for this sharing. The male would then go to his food bowl, grab two food flakes and give the other one to a female. It has been discovered that patterns of food-sharing among primates is due to reciprocity. Kin selection, strengthening social ties, and appeasing beggars are all reasons for this behavior (Silk & House 2011, 2011). After a group hunt, chimpanzees often share meat (de Waal and Suchak 2010). The hunted have an easier time accessing the food (de Waal and Suchak, 2010). The evolution of food sharing is vital. Food. Food is essential for survival and reproduction.
Altruism Other ExamplesAlarm calling is when a primate makes a loud cry to warn other primate species of an approaching threat (Silk (2002)). This puts the actor in danger while benefiting those around them. Orangutans often perform tree bridging (using their bodies as a bridge to help younger primate overhang two trees) because it is an altruistic gesture.
I was observing a De Brazza’s mother monkey in the field. Her young ones were still attached to her stomach. The strong bond that primates share is evident in such acts. In a study that examined altruism among chimpanzees, infants, and humans (Warneken and al. 2007), it was found that both chimpanzees as well as infants were willing to help strangers in the absence of any reward. Warneken et al. (2007) found that chimpanzees helped chimpanzees they were not related to.
Alarm calling may be an evolutionary motivation, in that it can ensure survival for many even though it could cost the caller’s life (Silk, 2002). Alarm calling alerts the group to a potential threat so that they can be prepared (Silk 2002). The tree bridging is seen as a survival tool for young chimpanzees, because it allows them to reach the next branch safely. Evolution is not harmful, perhaps a more accurate way to view it. It may be viewed as helping chimps in general, rather than just one’s own bloodline. It shows that we are similar to other primate species because both humans and other non-humans will assist conspecifics. Aggression is another similarity.
Psychologists define aggression as any action taken by a person with the intent to harm another without their consent (Baumeister & Bushman (2014)). The two types of aggression in humans are reactive aggression and proactive aggression. Reactive aggression is a spontaneous, emotional reaction to an insult, while proactive aggression is a planned, controlled behavior with definite goals (Nouvion et al., 2007).
The males are more aggressive toward opposite-sex people (Wolfer and Hewstone, 2014). Women, on the other hand, are more likely to display relational violence, like spreading rumors about a person or excluding him/her from a group. In humans, the majority of aggression occurs between familiar people.
Humans are able to use modern weapons in order to be aggressive (Cashdan & Downes 2012). Aggression can be anything from physical abuse of a spouse to fighting at bars to pushing someone to even murder. There are many reasons why humans can be aggressive. Infidelity and lying are among the causes of aggression. Provocation, jealousy and infidelity can also be factors. How do primates differ from each other when it’s about aggression?
The male mate defense hypothesis is one theory that explains aggression in primates. According to this theory, males become more aggressive when females are in heat (Kitchen & Beehner 2007). This theory is supported by evidence from chimps and Japanese macaques. Bonnet macaques are also in agreement with this theory. This is also the case with white-faced Sakis (Pithecia Pithecia), which have been found to exhibit intergroup aggression in order to gain exclusive access females.
The most aggressive female chacma babies are those in oestrous, which shows that they also fight to find mates. (Huchard and Cowlishaw 2011). Moreover pregnant chacma baboons initiated the most aggressive behavior, possibly because they were competing for food resources to ensure successful lactation and gestation (Huchard & Cowlishaw 2011, 2011). In polygamous baboons like the olive baboon (Papio baboon), males who are competitively strong will be chosen as mates, resulting an increased level of male aggression (Sapolsky, 2006). Mountain gorillas choose their mates by their fighting abilities (Robbins et al., 2014).
In addition to vocalizations or chasing conspecifics, aggression can also take on many other forms (Harris 2007, for example). The green monkey (Chlorocebus) displays aggression by threatening, chasing, biting, lunging and pushing (Chalyan & Meishvili).
Macaca mulatta is a macaque with a high level of aggression and biting. Green monkey males are more aggressive than females because they compete to gain high status or access to females. (Chalyan and Meishvili 2007).
De Filippis Chiarotti & Vitale (2009) found that aggression in marmosets increases when there are more than five members per family. Hanya (2009) studied the frequency of aggression among wild Japanese Macaques when they were feeding. Hanya (2009) found that the more feeding sites, the greater the aggression. In contrast, only high-quality foods like seeds and fruits were aggressively consumed, not leaves and flowers. Bwindi gorillas fight over food that is of high quality and takes longer to eat.
Kitchen found that Black howlers monkeys (Alouatta pgra) were more aggressive towards infants in the presence of small babies (as quoted in Wich and Sterck 2007). The lemurs of Lufkin Trout Zoo suddenly began making loud noises. The noises I heard were loud, and I was unsure what caused them. However, they seemed to be a warning. According to research, there are several factors that can lead to aggression.
The level of aggression as well as the primary target of that aggression varies between primates. In a group, monkeys with higher social status tended to be more aggressive towards their mid-ranking conspecifics than the opposite (Chalyan and Meishvili 2007). Bwindi gorillas also tend towards aggression in lower social ranks (Wright & Robbins (2014)). Conflicts in monkeys are usually between individuals, rather than between groups (Chalyan and Meishvili 2007).
In macaques, aggression can be bidirectional. Both parties may participate in it. Wich und Sterck (2007) observed that male Thomas thomasi (Presbytis theosi) displayed more aggression towards conspecifics they did not know and were unfamiliar with, than toward their own kin. Thomas langurs rarely fight (Wich & Steerck, 2007).
As opposed to Thomas langurs (de Waal, (2000), female macaques tend to fight with their sisters more than others who are unrelated. In marmosets, the majority of aggression is between siblings (de Filippis Chiarotti & Vitale 2009). Moor Macaques have low levels of aggression. Crested Black Macaques however, exhibit higher levels. This is likely due to their lack in affiliative behaviours, like grooming. Bwindi gorillas show lower levels of aggression than most primates. It may be because they are larger and can cause more serious injuries. We have now examined the evolution of primates’ aggression.
In many cases, aggression has been shown to be selected by sexual selection. Bravado is attractive to women. The sexual selection of aggressive behavior is important for humans as well as non-human primates. My hypothesis is that males show their aggressive side, which may be an indicator of his ability to protect. The primates use aggression as a way to protect themselves or to obtain food. Both are vital for survival. In chimpanzees, coalitionary aggressive behavior, where conspecifics band together and direct aggression against one or multiple conspecifics is shown to increase the reproductive success (Gilby et. al., 2013,). Richard Dawkins has proposed that our genes are primarily motivated by reproduction.
ConclusionAltruism and aggressiveness are important evolutionary elements. Both humans and non-human primate species can benefit from aggression, but it is more important to primates. In humans and other primates, it appears that sexual selection is the main cause behind altruism. It is clear that we are very similar to other primates.
