The killer ape theory or killer ape hypothesis is the theory that war and interpersonal aggression was the driving force behind human evolution. It was originated by Raymond Dart in the 1950s; it was developed further in African Genesis by Robert Ardrey in 1961. [1]
According to the theory, the ancestors of humans were distinguished from other primate species by their greater aggressiveness, and this aggression remains within humanity, which retains many murderous instincts.
The theory gained notoriety for suggesting that the urge to be violent was a fundamental part of human psychology. The hunting hypothesis is often associated with the theory, because of similarities and because Robert Ardrey developed both. However, both chimpanzees and bonobos have been observed to exhibit aggressive behaviors over 100 times more often than humans. [2]
The theory has variations as to what kind of violence served as the evolutionary catalyst: one-on-one aggression or group-based aggression.
The theory suggests [ citation needed ] the primary reason humans evolved bipedalism was to conserve energy after learning how to run, and to free up the use of upper limbs.[ citation needed ] The killer ape theory posits that violence was a driving factor in evolving bipedalism, with violence motivating the use of upper limbs to wield weapons.[ citation needed ]
In Creatures of Cain: The Hunt for Human Nature in Cold War America by Erika Lorraine Milam (2018), she states that, "in the 1970s, the theory unraveled altogether when primatologists discovered that chimpanzees also kill members of their own species." The fact that chimpanzees attack their own species raises questions about if interpersonal violence derives from biological or social factors.
The expression "killer ape" does not mean an outstandingly aggressive kind of ape; in fact, the term refers to anthropological analysis of human aggression. Accordingly, the killer ape is a notably belligerent species on which our instincts might be rooted, because this very ancestor could establish itself due to its special aggression.
Raymond A. Dart (1893–1988) originated the hypothesis in his article "The predatory transition from ape to man" (1953). [3]
Ethologist Konrad Lorenz showed interest in similar ideas in his book On Aggression (1963). [4] In his introduction, he describes how rival butterfly fish defend their territories, leading him to raise the question of whether humans, too, tend to intraspecific conflict.
A 1984 article said Dart's evidence was slim, and was refuted by paleontologists in the early 1970's, in particular CK Brain and Elisabeth Vrba. [5]
A 2008 article in Nature by Dan Jones stated, "A growing number of psychologists, neuroscientists, and anthropologists have accumulated evidence that understanding many aspects of antisocial behaviour, including violence and murder, requires the study of brains, genes, and evolution, as well as the societies those factors have wrought." Evolutionary psychologists generally argue that violence is not done for its own sake, but is a by-product of goals such as higher status or reproductive success. Some evolutionary psychologists argue that humans have specific mechanisms for specific forms of violence such as against stepchildren (the Cinderella effect). Chimpanzees have violence between groups, which are similar to raids and violence between human groups in nonstate societies, and produce similar death rates. [6] [7] On the other hand, intragroup violence is lower among humans living in small-group societies than among chimpanzees. Humans may have a strong tendency to differ between ingroup and outgroup, which affects altruistic and aggressive behavior. Also, evidence exists that both intragroup and intergroup violence were much more prevalent in the recent past and in tribal societies. This suggests that tendencies to use violence to achieve goals are affected by social mores. Reduced inequalities, more available resources, and reduced blood feuds due to better-functioning justice systems may have contributed to declining intragroup violence. [8]
The idea that man is naturally warlike has been challenged, for example in the book War, Peace, and Human Nature (2013), edited by Douglas P. Fry. [9] The Seville Statement on Violence, released under UNESCO auspices in 1986, specifically rejects any genetic basis to violence or warfare though is considered outdated in light of more contemporary studies. More modern research and criticism has focused on misinterpretations of fossil evidence, lack of research into other apes, and the political climate of the Cold War. [10] [11]
 | This article needs additional citations for verification .(May 2023) |
The association of intraspecies and interspecies violence with a quantum leap in human evolution can be seen in the opening sequence of 2001: A Space Odyssey .
The television show Sliders made extensive use of the killer ape theory in storyline arcs involving the Kromaggs.
Bipedalism is a form of terrestrial locomotion where a tetrapod moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped, meaning 'two feet'. Types of bipedal movement include walking or running and hopping.
Homininae, also called "African hominids" or "African apes", is a subfamily of Hominidae. It includes two tribes, with their extant as well as extinct species: 1) the tribe Hominini ―and 2) the tribe Gorillini (gorillas). Alternatively, the genus Pan is sometimes considered to belong to its own third tribe, Panini. Homininae comprises all hominids that arose after orangutans split from the line of great apes. The Homininae cladogram has three main branches, which lead to gorillas, and to humans and chimpanzees via the tribe Hominini and subtribes Hominina and Panina. There are two living species of Panina and two living species of gorillas, but only one extant human species. Traces of extinct Homo species, including Homo floresiensis have been found with dates as recent as 40,000 years ago. Organisms in this subfamily are described as hominine or hominines.
The bonobo, also historically called the pygmy chimpanzee, is an endangered great ape and one of the two species making up the genus Pan. While bonobos are, today, recognized as a distinct species in their own right, they were initially thought to be a subspecies of Pan troglodytes, due to the physical similarities between the two species. Taxonomically, the members of the chimpanzee/bonobo subtribe Panina—composed entirely by the genus Pan—are collectively termed panins.
The aquatic ape hypothesis (AAH), also referred to as aquatic ape theory (AAT) or the waterside hypothesis of human evolution, postulates that the ancestors of modern humans took a divergent evolutionary pathway from the other great apes by becoming adapted to a more aquatic habitat. While the hypothesis has some popularity with the lay public, it is generally ignored or classified as pseudoscience by anthropologists.
Raymond Arthur Dart was an Australian anatomist and anthropologist, best known for his involvement in the 1924 discovery of the first fossil found of Australopithecus africanus, an extinct hominin closely related to humans, at Taung in the North of South Africa in the Northwest province.
Franciscus Bernardus Maria "Frans" de Waal is a Dutch primatologist and ethologist. He is the Charles Howard Candler Professor of Primate Behavior in the Department of Psychology at Emory University in Atlanta, Georgia, director of the Living Links Center at the Yerkes National Primate Research Center at Emory, and author of numerous books including Chimpanzee Politics (1982) and Our Inner Ape (2005). His research centers on primate social behavior, including conflict resolution, cooperation, inequity aversion, and food-sharing. He is a member of the United States National Academy of Sciences and the Royal Netherlands Academy of Arts and Sciences.
On Aggression is a 1963 book by the ethologist Konrad Lorenz; it was translated into English in 1966. As he writes in the prologue, "the subject of this book is aggression, that is to say the fighting instinct in beast and man which is directed against members of the same species."
Knuckle-walking is a form of quadrupedal walking in which the forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles. Gorillas and chimpanzees use this style of locomotion, as do anteaters and platypuses.
Robert Ardrey was an American playwright, screenwriter and science writer perhaps best known for The Territorial Imperative (1966). After a Broadway and Hollywood career, he returned to his academic training in anthropology and the behavioral sciences in the 1950s.
Richard Walter Wrangham is an English anthropologist and primatologist; he is Professor of Biological Anthropology at Harvard University. His research and writing have involved ape behavior, human evolution, violence, and cooking.
A facultative biped is an animal that is capable of walking or running on two legs (bipedal), as a response to exceptional circumstances (facultative), while normally walking or running on four limbs or more. In contrast, obligate bipedalism is where walking or running on two legs is the primary method of locomotion. Facultative bipedalism has been observed in several families of lizards and multiple species of primates, including sifakas, capuchin monkeys, baboons, gibbons, gorillas, bonobos and chimpanzees. Different facultatively bipedal species employ different types of bipedalism corresponding to the varying reasons they have for engaging in facultative bipedalism. In primates, bipedalism is often associated with food gathering and transport. In lizards, it has been debated whether bipedal locomotion is an advantage for speed and energy conservation or whether it is governed solely by the mechanics of the acceleration and lizard's center of mass. Facultative bipedalism is often divided into high-speed (lizards) and low-speed (gibbons), but some species cannot be easily categorized into one of these two. Facultative bipedalism has also been observed in cockroaches and some desert rodents.
Demonic Males: Apes and the Origins of Human Violence is a 1996 book by Richard Wrangham and Dale Peterson examining the evolutionary factors leading to human male violence.
The Territorial Imperative: A Personal Inquiry Into the Animal Origins of Property and Nations is a 1966 nonfiction book by American writer Robert Ardrey. It describes the evolutionarily determined instinct among humans toward territoriality and the implications of this territoriality in human meta-phenomena such as property ownership and nation building. The Territorial Imperative was an immediate success and remains a widely influential work of popular science. It extended Ardrey's groundbreaking anthropological work, contributed to the development of the science of ethology, and encouraged an increasing public interest in human origins.
African Genesis: A Personal Investigation into the Animal Origins and Nature of Man, usually referred to as African Genesis, is a 1961 nonfiction work by the American writer Robert Ardrey. It posited the hypothesis that man evolved on the African continent from carnivorous, predatory ancestors who distinguished themselves from apes by the use of weapons. The work bears on questions of human origins, human nature, and human uniqueness. It has been widely read and continues to inspire significant controversy.
The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder is a 1970 book by Robert Ardrey. It is the third in his four-book Nature of Man Series.
The Nature of Man Series is a four-volume series of works in paleoanthropology by the prolific playwright, screenwriter, and science writer Robert Ardrey. The books in the series were published between 1961 and 1976.
Animal faith is the study of animal behaviours that suggest proto-religious faith. Whether non-human animals can have religious faith is dependent on a sufficiently open definition of religion. Thus, if by religion one means a "non-anthropocentric, non-anthropomorphic, non-theistic, and non-logocentric [behavioural and ritualistic] trans-species prototype definition of religion", ritual behaviour can be interpreted in the actions of chimpanzees, elephants, dolphins and other animals.
The savannah hypothesis is a hypothesis that human bipedalism evolved as a direct result of human ancestors' transition from an arboreal lifestyle to one on the savannas. According to the hypothesis, hominins left the woodlands that had previously been their natural habitat millions of years ago and adapted to their new habitat by walking upright.
The amity–enmity complex theory was introduced by Sir Arthur Keith in his work, A New Theory of Human Evolution (1948). He posited that humans evolved as differing races, tribes, and cultures, exhibiting patriotism, morality, leadership and nationalism. Those who belong are part of the in-group, and tolerated; all others are classed as out-group, and subject to hostility: "The code of enmity is a necessary part of the machinery of evolution. He who feels generous towards his enemy... has given up his place in the turmoil of evolutionary competition."
Survival of the Friendliest: Understanding Our Origins and Rediscovering Our Common Humanity is a book by anthropologist Brian Hare and writer Vanessa Woods, first published in 2020, based on Hare's research hypothesis of human self-domestication. The main thesis of the book is that late in human evolution Homo sapiens underwent a process of extreme selection for friendliness that led to the self-domestication syndrome, as seen in other animals. The self-domestication syndrome led to a series of cognitive changes that allowed modern humans to out compete other species of humans in the Pleistocene, including Neanderthals, and become the most successful mammal on the planet. Hare and Woods argue that self-domestication is an ongoing process that continues today.
| Taxonomy (Hominins) |
| ||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ancestors |
| ||||||||||||||||||||||||||
| Models |
| ||||||||||||||||||||||||||
| Timelines | |||||||||||||||||||||||||||
| Others | |||||||||||||||||||||||||||
