Domestication and Human/Wildlife Mutualism

Abstract

In this study, I discuss recent studies of human/wildlife mutualisms and suggest that several cases considered to represent domestication that has arisen through commensalism would be better considered as examples of mutualism between humans and various wild species. Species discussed include the only domesticated carnivores: cats (Felis sylvestris) and wolves (Canis lupus and C. dingo). I also discuss species over which there is considerable debate about whether they are domesticated or not: African (Loxodonta) and Asiatic elephants (Elphas). All of these species’ interactions include niche construction on the part of both species and influence human evolution at least a cultural level. I further argue that most contemporary domestic species currently exist in mutualistic relationships with humans because even though all of these species have been selected to benefit humans, all domestica species have also benefitted in terms of increased global and local population sizes and from more secure living conditions than can be found in their wild ancestors.

1. Introduction

In recent years, there has been increased emphasis on mutualistic interactions between humans and wild (nondomestic) species [1,2]. This is an important area of investigation; however, as currently defined, the concept excludes a number of important examples of possible mutualistic interactions while also ignoring the historical component of relationships between humans and more-than-human animals that involve niche construction and its impacts on species dynamics [3].

Niche construction is a relatively new concept in evolutionary biology based on ideas first developed by Richard Lewontin in the 1980s and expanded by Laland and others in the 21st century [4,5,6,7]. The basic idea is that, through their actions, organisms influence other species that are part of their ecosystem, having either positive or negative impacts, thereby influencing the evolutionary trajectories of the latter. Mutualistic interactions and ecosystem engineering are examples of positive impacts, whereas predation and competition would be considered negative impacts. The classic example is how earthworms construct the environment in which they and thousands of other species live by creating soil through their foraging and digestion, which becomes a crucial aspect of ecological niches for thousands of other species. One important theme from the perspective of this paper is that Homo sapiens is one the most important niche-constructing species on the planet [3] because all the species we interact with are impacted by our activities in various ways. Another way to think about this is that wherever humans are present, they cause major disruption of the local ecosystem, compared to the state in which it would exist if they were not present. I refer not only to Europeans but also to Indigenous cultures. Native Americans altered every environment in which they lived, even though they worked to minimize negative impacts [8].

Among those activities over the last 10,000 years has been the domestication of various animals and plants [9,10]. As far as I can determine, no one has linked domestication and niche construction, although it seems that these concepts deserve to be linked. Domestication clearly involves niche construction because the niches of both humans and more-than-humans were clearly impacted by the processes involved. It is important to emphasize that relationships among species should be considered as processes rather than outcomes, and these processes continue to this day. “The Process of domestication must be disassociated from that of the domestic animal, which is the possible result of the process” [10], p. 173. By considering specific temporal and chronological patterns of individual animal species within an evolutionary context, we are much closer to revealing and comprehending the nature of the origins of domestication. This paper should establish why it is important to consider domestication as an evolutionary process that impacts both species involved. This is a major reason we include elephants as an example, as most scholars seem to be unsure about whether elephants should be considered domesticated. As a result, the process seems to be ongoing and complex (see below).

According to Zeder [11], there are three separate pathways to domestication: (1) commensal, (2) predator/prey, and (3) directed domestication (the result of deliberate human action). All of these are presumed to represent co-evolutionary pathways and, in combination, reveal a framework that allows comprehensive consideration of accidental and intentional selective pressures associated within the context of how separate species encountered and adjusted to the human niche [12]. The problem I see is that arguments like the one developed by Zeder is that it seems to assume that contemporary relationships represent the pathways through which domestication occurred. This ignores important evidence, such as the fact that cattle, assumed to have become domesticated through the prey pathway, were used as beasts of burden very quickly after domestication occurred, whereas horses, which have been assumed to be a classic example of direct domestication, served as prey for several millennia before they were used as beasts of burden, which apparently only happened within the last 4000 years [13]. Zeder’s assumption that horses can be considered an example of directed domestication appears to be because most cultures no longer assume that horses should be eaten by humans.

In this paper, I focus on the commensal pathway, which I think was overemphasized in early studies of animal domestication. To me, it seems more likely that mutualistic relationships have acted through protracted co-evolutionary processes with multiple stages along different pathways to produce domestic forms. In many such situations, humans probably did not intend to domesticate animals (at least, they never envisioned a domesticated animal resulting) from the mutualistic pathway; however, they became entangled with these species as the relationship between them and the human role in their survival and reproduction intensified [9], p. 130. The key point is the role of intention, i.e., whether the humans started with a plan or simply allowed things to develop out of a pre-existing commensal or mutualistic relationship. Many people assume that humans drive domestication; however, in the examples I examine, the roles of the human participants are quite different from those that exist in the contemporary world. In contrast, commensalism is defined as two species coexisting where one species benefits from the relationship and the other does not; however, many such cases can shade easily into mutualism, where both species benefit in an evolutionary context.

What remains largely unexplored is how domestication can readily arise from a mutualistic relationship. Many scholars of European ancestry appear to be uncomfortable with this idea, preferring to define mutualist relationships with humans only in terms of what they consider obviously nondomestic species, e.g., honeyguides (Indicator spp.) and cetaceans, such as bottlenose dolphins (Tursiops spp.), orcas (Orcinus orca) and Irrawaddy dolphins (Orcaella), along with one exception, in the beginnings of a current example of domestication, gray wolves in North America [1,2]. Several other human/more-than-human mutualistic relationships clearly exist where the boundary between domestic and free living is not well defined. These are the cases I examine in this paper.

2. Methods

This article is the result of insights gained through behavioral research on wolf/human interactions that began during my PhD work in the 1970s, continuing while I was a postdoctoral fellow at the University of New Mexico, and remains active today. I have also studied the relationship between cats and humans in several contexts, from fully socialized to feral. Work on dingoes began in 2012 when I was working with my MA student Brandy Fogg in ethnobiology, which continued while Ms. Fogg and I worked on our book, The First Domestication: How Wolves and Humans Co-evolved [12]. Through these efforts, I became an expert in evaluating various stages involved in domestication as a co-evolutionary process.

In contrast to Western numerical data, we emphasized traditional stories from Indigenous peoples that provided insights into their relationships with wild canids throughout their cultural histories. We regard these accounts to more completely and accurately describe the ecological and social beginnings of relationships between species than can be discerned through archaeological approaches. These accounts include recent descriptions of interactions revealing why this relationship should be regarded as co-evolutionary and mutualistic rather than simply commensal. This approach also involves humans from a variety of cultural traditions that interact with wolves and their domesticated descendants, whom we currently describe as “dogs” (in reality, domesticated wolves). This work can also be considered as part of my collaboration with the Human/Wildlife Mutualism Workshop [1,2].

3. Results and Discussion

3.1. Interactions with Carnivores

Commensalism and mutualism are often confused, not only by laypeople but even by scientists. This becomes obvious if we look at the only two species of obviously wild carnivores that humans have domesticated: the wolf, Canis lupus, and the wildcat, Felis sylvestris. I do not consider mink and foxes bred on fur farms to be domestic because there is no consistent and widespread ecological and social relationship between humans and these species.

I begin by discussing cats, which, for the most part, are little changed from their wild ancestors and are considered to be members of the same species. It is important to realize that serious students of evolution consider domestic forms to be conspecific with their wild ancestors. There are no Canis familiaris or Felis catus among real scientists [14]. The general consensus is that cats did not live with humans until humans developed grain-based agriculture around 10,000 ybp [15]. At this point, humans began to store harvested grain in granaries, which attracted large numbers of rodents, in turn drawing wildcats to this new, locally abundant food source. In doing this, the cats provided an important service to humans, i.e., removing large numbers of competitors and contaminators for the stored grain.

Many scholars consider this relationship to be commensal, i.e., humans benefit from the activities of the cats. To me, this is clearly a mutualistic relationship in which both species benefit, and is also a classic example of human niche construction because the human granaries presented a new type of habitat that attracted rodent prey [5]. The benefits to humans are obvious, as were the benefits to the wildcats, who had free access to a rich source of food. I assume that humans recognized the value of having small, efficient predators around to protect their food stores. Although we will never know the details, I also assume that humans began to act in ways that would encourage the cats to stay, and over time, individual humans or human families developed personal relationships with individual wildcats. As wildcats continued to breed and evolve, their offspring were born into environments in which human presence was a constant, and the social dynamic became ever more interdependent.

The irony about the human–cat relationship is that it seems to have become less mutualistic and more commensal over time, with many people keeping “indoor cats” because they are concerned that their small companion predators may become prey of larger predators. What benefits humans gain now seem to be social rather than ecological. Interestingly, cats are also the species most likely to become truly feral, which is how we describe domestic animals that return to living in a wild state [12], chapter 9. Cats are the most independent of domestic species, readily leaving humans behind if they do not like the living conditions. I lived with a feral cat for 19 years, although her primary social alliance was not with her human companions but with her equid companions [12], chapter 9.

The other carnivore humans domesticated is the gray wolf. Once again, many scholars choose to argue that this relationship was initially commensal, in this case, with the wolves benefitting and humans gaining no advantage. This is based entirely on the assumption that his relationship was initiated because wolves scavenged remains and inedible parts of killed prey left by humans. This assumption allows followers to consider wolves as commensal, benefitting from the activities of humans, whereas humans received no benefit [16,17].

The problem with this line of thought is twofold; first, it assumes that there is no benefit to having another species clean up your leavings before they decay, drawing insects, or providing sites for bacterial and fungal growth. More significantly, wolves associating with a human habitation site almost certainly would serve as a warning system against other predators or scavengers [12]. Many scholars of European ancestry assume that these events happened only in the last 10,000–15,000 years because that fits into their idea of human prehistory, i.e., assuming that wolves/dogs were completely dependent on humans. This is a false assumption based on the “findings” of Ray Coppinger [12], chapter 1, who describes the relationship of dogs to humans as “slavery”:

To understand the Coppingers’ thinking, it is essential to read their chapter on household dogs. They describe this relationship as dulosis, or “slave-making”, because dogs are “forced” to work for humans (255). They refer to dingoes as “crop pests” (280), a pejorative term apparently meant to suggest that dingoes can survive only by scavenging off human activities, a proposition that would offend most Australian Aboriginal people,—not to mention that Aboriginals did not have crops as such; therefore, this insult is cast totally within a colonial mind-set.

The Coppingers argue that dogs represent a huge drain on the economy and the ecosystem because they require large expenditures on food and care. This line of thinking misses the essence of the relationship—many humans value their dogs as they value other humans, as companions that support you, protect you, provide comfort, and can even catch food for you. This is understood by trappers and herders in central Siberia, Indigenous peoples of the Americas, and Australian Aboriginals as well as by untold numbers of people in Europe and North America who value their canid companions [12], p. 36.

Another scholar reacted to the Coppinger’s ideas in this fashion:

One of these ideas [about how dogs evolved from wolves] is that wolves evolved as scavengers, hanging around human camps. Anyone who has lived in wolf country… would find this untenable. Wolves don’t scavenge, unless they’re starving, or if they opportunistically stumble upon another predator’s kill… human camps don’t usually leave enough meaty refuse to attract a wolf, although they often visit camps out of curiosity… A large mammal carcass would attract a wolf; but humans have been using tools to clean meat from bones for more than [a] million years, and by about 15,000 years ago, when the first unequivocal dogs appear in the archaeological record, humans were very efficient at cleaning up the bones and extracting the marrow. The leftovers would not feed even one wolf, let alone a pack. Human settlements leave enough refuse; but these only appear about 10,000 ybp [12], pp. 31–32.

If we consider an alternative view that addresses the reality of the human/wolf relationship as described in Aboriginal accounts, it becomes obvious that this relationship is much more ancient, having its roots at least 30,000 and perhaps 40,000 years before the present era [12,18,19,20,21,22]. These events took place well before the time of permanent human settlements, which are necessary for the “scavenger wolf” hypothesis advanced by the Coppingers. More to the point, [12,23]. According to Indigenous peoples, the relationship with wolves began as mutualism and may or may not proceed to domestication, e.g., some Indigenous Americans produced dogs, e.g., the wool dogs of the Salish peoples, Alaskan Malemutes, Greenland and Eskimo dogs, the South American hairless breeds [24]. What is significant is that until about 200 years ago, most of the dogs found in North America were almost certainly wolves, living in a mutualistic relationship with Indigenous humans [12,23]. European explorers in North America consistently stated that dogs in Indian camps were indistinguishable from wolves. There are also numerous accounts of wolves that did not live with tribes, rescuing humans, providing food, and guarding them until they could safely return to a tribal encampment [23]. These are obvious mutualistic relationships, which tribes repay to this day by protecting wolves, creating sanctuaries for them on tribal lands [12], pp. 288–290.

Another thing to keep in mind is that some Indigenous Nations regard wolves as “creator” figures [12], chapter 8. Unlike creators imagined by Christian denominations of an anthropomorphic being that makes all decisions and shapes every life form, wolves are considered by Indigenous peoples as an interactive species that, through its actions within an ecosystem, shapes the lives of virtually every other species in some ways, through the process of niche construction and involving Trophic Cascades [3,5,6]. This concept does, however, have major implications for what we should assume about the relationships between humans and wolves and what we mean when we use the term “domestication”. Clearly, wolves are recognized as having existed before humans (creators must be more ancient than their “creations”; [8]). More to the point, few humans would consider trying to deliberately domesticate a species that they regard as being as basically equal to themselves.

As humans became more “civilized”, they became less comfortable with the very basic reality of living with actual nondomestic wolves. Instead, they preferred companion animals that were more childlike and neotenic, desiring creatures more amenable to their own nature, so they created “dogs” [12]. Wolves were as loyal socially as dogs, but they are less inclined to act in a juvenile fashion, which seems to be what most contemporary humans want in a companion. One problem is that the line between domestic and nondomestic, i.e., between dogs and wolves, is not clearly defined, especially during the 20,000 years or so when humans were living alongside wolves, and there were no obvious “dog” phenotypes that could be identified as “domestic”, i.e., easily distinguished from wolves [12]. What is obvious, however rarely discussed, is that some domestic breeds are much more wolflike than others. Another topic rarely discussed is that such “dogs” are rarely included in genetic studies of the phylogeny of domestic dogs.

One descendant of wolves has achieved the status of a separate species or subspecies, the dingo, Canis dingo, of Australia. Relationships between dingoes and Australian Indigenous peoples are so well established but nondomestic in nature that these peoples state that “Dingo makes us Human” [25,26,27] in recognition of their close, mutualistic ties. Contemporary scholars have avoided including dingoes in the list of human/wildlife mutualisms because they are considered to be domestic animals that arrived in Australia in the last 8500 years [27]. Despite this assumption, dingoes represent an intriguing case within canine evolution, having been geographically isolated for thousands of years, with distinct demographic and environmental conditions that shaped the dingo genome [27]. As a result, dingoes should not be considered part of Canis lupus familiaris, which is a grab bag category. The root problem is that there is in actuality no definable taxonomic entity (species or subspecies) that can be identified as “the domestic dog,” a category characterized by a specific set of physical, behavioral, or physiological traits that differentiate it from wolves and other canids. The sole criterion for identifying domestic dogs is that they be some domestic form of Canis lupus [12], p. 25. This explains why, as a species, C. familiaris has no defined characteristics other than the “domestic version of Canis”, in which case, species identity depends entirely on the definition of domestic, a term open to a number of interpretations, as discussed in this paper.

The issue with dingoes is that they came from a lineage that was apparently partially domesticated, in the sense that human actions produced a new but consistent species phenotype demonstrably different than gray wolves, being smaller, with “tawny” coloration, resembling various quasi-domesticated dogs from southern Asia and Oceania. These include the New Guinea singing dog, Canis hallstromi [28], which is named after its unusual high-pitched howls. Dingoes and singing dogs do not bark; however, they have very high-pitched howls. Dingo and hallstromi are wild animals, closely related, and probably constitute a distinct evolutionary lineage of wild dog.

What is fascinating about dingoes and singing dogs is their apparent lack of domestic traits despite close working relationships with humans in dingoes. The late Deborah Rose, the author of Dingo Makes Us Human [25,26], described how dingoes functioned as a deep part of Aboriginal life. “The dingoes had names, they had kinship classifications, which makes them so unlike all other animals in Australia, … They had a place at the campfire” [29]. An Australian anthropologist described this relationship:

Aboriginal Australians are known to have routinely taken dingo pups from wild dens to rear as companion animals, with the mature canids typically returning to the bush to mate. Available accounts emphasise the strong emotional bonds between Indigenous people and “camp dingoes”, which were essentially raised as though they were human… despite the closeness of human–canine relations in Australia, … Aboriginal people did not domesticate dingoes… while the dingoes lived part of their lives with humans, they were ultimately “free agents” that foraged and reproduced independently… (this) generated a distinct population of free-roaming adult dingoes that were socialised to interact with humans and may have remained loosely associated with them… this hitherto unrecognised dingo ecotype, … involved management and domestication processes, but not as conventionally defined (controlled breeding, artificial selection) [30], p. 1.

In the case of dingoes, Aboriginal Australians seem to have gone to extraordinary lengths to build their relationships with these wild canids. This includes carrying puppies, with women even suckling puppies [30]. Dingoes raised by humans were given personal names and kin classification (“skin identities”), along with the notion of shared kinship that began in the Dreamtime [26], p. 176. “Despite the intuitive impressions of early European observers, present-day authorities do not consider the close association between Aboriginal people and dingoes to constitute a relationship of domestication” [30], p. 3. This is because domestication is typically assumed to involve directed breeding, which leads to morphological changes relative to the ancestral population. In this case, the humans seem to have been perfectly contented with the phenotype and behavior of wild dingoes, which is probably quite similar to the reaction of humans around the world to their interactions with wolves until the last 10,000 years or so; much more recently with Aboriginal Americans and the Ainu of Japan [12], chapter 5.

The domesticated/wild binary is clearly an inadequate classificatory tool for thinking about canines cross-culturally, because the options for human–animal relations are not either total control over breeding or a complete absence of human engagement, as European notions have often framed domestication [31], p. 89.

Understanding how Indigenous peoples treat more-than-human companions presents a very different perspective than is seen in typical “domestication” as perceived by contemporary Europeans. As one example of the human/dingo relationship, an aboriginal couple, Warri and Yatungka of the Mandildjara, resisted attempts by the Australian government to force them to move into a colonial town and remain in the Gibson Desert of Western Australia [32]. After 30 years, their people were concerned about them as they aged and sent a party to find them and basically force them into subjugation. When they were located, they were accompanied by three dingoes. They were asked if they wanted to bring their dingoes with them. They indicated that the dingoes were not theirs but independent and would remain in their “home” [32]. This account indicates several things: (1) Australian aboriginal people lived with dingoes who were functionally capable of existing without humans (the reverse might not have been true), and (2) the humans respected and honored the independence of their companions despite their close bonds. The Mandildjara story reveals that if a species acted as a valuable companion, even perhaps a colleague, there was little need to work to alter the existing phenotype. In such situations, the two species influenced one another through a co-evolutionary pathway that increased the fitness of both species, which is classic niche construction [3,4,12,21].

This calls into question the often-invoked role of commensalism as a path to domestication. In Western science, there are at least three tendencies that interfere with creative approaches to understanding relationships between humans and more-than-humans. First is the tendency to emphasize negative dynamics over positive ones, especially competition between species, which dates back to Darwin and the original concepts of how natural selection functions [12], chapter 2. One of the strengths of the concept of niche construction is that it emphasizes influences by which species interactions lead to positive evolutionary outcomes [3,4]. In the case of wolves and their descendant, dingo, these large wild canids and their human companions created situations where the two species could be a major factor in constructing each others’ niches. This led to a very close mutualistic relationship, which, in the Old World, led to the domestication of wolves, eventually producing dogs, the species with whom we currently have the closest relationship ever evolved between two mammal species.

The second tendency inhibiting creative thought in Western Science is the idea that humans must control every interspecies relationship in which they participate. This is the flaw in the Coppingers’ idea that dogs became dependent slaves for humans because they relied on our waste as a primary food source [16]. Unfortunately, their idea resonated with a lot of people who work with dogs, which can readily be seen in studies conducted by their intellectual descendants [33]. These scholars focus on how they think dogs and wolves differ more than what they share in common. One of their key “findings” is that allegedly dogs will look in the direction in which humans point, whereas wolves supposedly lack this “skill”. This finding appears to be the result of bias. These scholars never raised wolves to work with them, and wolves will not follow the instructions of unfamiliar humans. When wolves have been raised with or by humans doing the pointing, they pay just as close attention as any dog [34]. Comparing wolves to naïve pet dogs of the same age revealed that during several months of formal training, wolves achieve the same level as dogs in their success in following momentary distal pointing in parallel with improving their readiness to form eye contact with a human experimenter [35,36]. In contrast, human-socialized wolves are fully capable of responding to pointing gestures using the arm and hand and are sensitive to a wide range of human gestures when given the opportunity to utilize such gestures in an object–choice task. Claims that domestic dogs are unique in their ability to respond to diverse novel stimuli seem to be a result of the absence of data for the same range of gestures in other species [34]. Aboriginal peoples from both Australia and North America lived closely with wild, rather than domestic, dogs, but they still engaged in training their canid companions [23,31]. It is also reported that Indigenous Americans sometimes survived by scavenging wolf kills and that the two species shared kills with each other [12]. They were not competitors but mutualistic collaborators.

The final bias in Western Science has been the tendency to ignore, or even discredit, the participation of women in these activities. It is very likely that women, rather than men, were instrumental in establishing the initial relationships, e.g., the tendency of women to suckle wolf and dingo puppies, an action from which males are obviously excluded. It is not surprising that the scholars who emphasize the strength of human/canid bonds are predominantly women, e.g., Rose, Fogg, Shipman, Udell, Viranyi, Range. In my experience, wolves are much more comfortable with females than with male humans. As an example, I was the only male with whom my two wolves developed a close relationship, but they had multiple close relationships with women [12], chapter 11.

All this suggests that the relationships humans have with carnivores could lead to domestication starting off not as commensal but as mutualistic, involving extensive cooperation and coevolution through Niche Construction. This is not an original idea; this approach was inspired by the work of the insightful German ethologist Wolfgang Schleidt [37], who posed the question, ‘Is humaneness canine?’ Schleidt’s argument was that the social behavior of modern humans is likely to have been influenced by their relationship with wolves and posited an “alternative view of dog domestication”, suggesting that the scientific name for modern humans might be more accurate as Homo homini lupus [38]. One major piece of evidence supporting this idea is that wolves share with humans a similar family structure This means that wolves/dogs adjust easily to joining human groups [12,37,38,39].

Early modern humans would have learned quickly of the benefits arising from sharing their lives with wolves. We know little about the social systems of prehistoric humans, but we do know there are five species of great apes: gorillas, orangutans, chimpanzees, bonobos, and humans. Humans are the only species of ape to live in monogamous family groups, which include grown offspring [12], chapter 3. Monogamy is quite rare in large mammals, with less than five percent of more than 4000 mammalian species practicing any form of monogamy [40]. Mammalian infants require breast-feeding, a role which can only be fulfilled by females. By definition, males of most mammal species are unequipped to feed their young; therefore, they would not necessarily benefit from a social structure that supports paternal care, and their evolution would not have favored monogamy. Despite its rarity among other mammalian species, all 35 species of canid [41] are monogamous with paternal care [42]. This means that canids represent more than 20% of all monogamous mammals globally and that modern humans are convergent upon canids in their social system. All species in which males typically help care for their young are monogamous. Humans are the only species of great ape that shows extensive paternal care, a characteristic shared with wolves [12], chapter 3.

It seems possible that the current social system shown by humans may have been copied from wolves, a widespread, successful species of group-hunting carnivore, with which humans have been known to associate in the last 30,000–40,000 years [12], chapter 3, [22]. Ironically, the one canid that does not typically show male parental care is the domestic dog. There are several reasons for this. Humans take over as surrogate male parents, providing food and shelter, which reduces the need for paternal care in dogs. Most importantly, humans have selected dogs to show neotenic traits carried into adulthood. As a result, dogs are much slower to mature than wolves, which means that they are often not ready to assume adult roles, such as parenting [12].

It is important to emphasize that when most people think of dogs, they think primarily of contemporary breeds, which are a very recent phenomenon [43,44]. Victorians, influenced by the ideas of Darwin, were obsessed with breeding for the ideal of a certain breed. Many of the conformational traits we think of as classic for a certain type of dog have their origins in this era. As a result, most dog breeds we recognize today were developed in the last 150 years. During this time in Great Britain, dog breeding intensified and expanded, resulting in many of our most recognizable breeds of dogs (source: https://www.morrisanimalfoundation.org/article/evolution-of-dogs, accessed on 8 September 2024). As one example, geneticists investigating canid phylogeny suggest that German shepherds have no more wolf ancestry than other “dogs” [45,46]. The history of the breed suggests otherwise. German shepherds (Alsatians) did not really appear as a distinct phenotype until the 1890s. Among the animals used in the development of this breed of dog were wolves [12]. American wolf breeder Gordon Smith further stated that some domesticated wolf lines had their papers switched with AKC-registered American German shepherds in order to produce better-looking “German shepherds.” [43], pp. 205–207.

A recent publication on the multiple origins of dogs [45] places German shepherds with other breeds known to involve crossing with wolves, such as the Czech wolfdog, and among ancient spitz breeds. This is in stark contrast to other genetic results, which place German shepherds with working dogs such as schnauzers and Portuguese water dogs [46]. At the very least, neither of these DNA-based published results can be correct. Frantz et al. [45] are the first investigators looking at DNA evidence in dogs to have included DNA from Czech and Saarloos wolfdogs. No one has examined DNA from central Asian laiki, North American Indian dogs, or any of the Belgian shepherd (sheepdog) breeds, which are among the most wolflike in appearance of recognized breeds [12], pp. 45–46.

3.2. Interactions with Elephants

As mentioned above, elephants clearly do not fall into any of the established pathways for how animals become domesticated. It is obvious that they are not prey and also that humans have not been making decisions about how to direct domestication in these large, intelligent organisms [9]. In general, elephants are sometimes left out of discussions of Mammalian domesticates because humans do not seem to have selectively modified them in any discernable way [47,48]. This creates a unique evolutionary perspective not found in other species that have relationships with humans. Zeder [11] makes the following statement:

In some ways (elephants) qualify as domesticates in that they are engaged in a sustained, multigenerational relationship with humans, in which humans assume considerable control over their movement, feeding, and protection to extract specific resources… since they are not bred in captivity, the normal array of selective factors responsible for creating domestic genotypes in other animal domesticates never come into play. Instead of passing on selected domestication traits to each new generation, the process of domestication begins anew with each animal tamed for these purposes. This unusual outlier case… raises interesting questions about the nature of the domestic relationship and whether it should be viewed more in terms… (of) the impact of this use on the evolutionary trajectory of the animal (p. 177).

When elephants are discussed, it is primarily Asiatic elephants (Elphas) that are considered. There is some evidence that African elephants (Loxodonta) have also been tamed, but the prime example of tamed African elephants seems to be Hannibal and his attempted invasion of Rome [49]. Larson and Fuller [9] do not even include elephants in their review of domesticated species. In contrast, the human–elephant mutualistic relationship is not considered by the scholars studying human–wildlife mutualisms because elephants (at least Asiatic) are considered to be domestic (R. Pierotti, personal observation). Elephants are the great enigma of domestication. From a biological perspective, the Asian elephant is a wild animal that has never been made a domestic animal [48], which creates an evolutionary conundrum.

Elephants are the most physically powerful land animals, with essentially no predators as adults. In consequence, one research team refers to attempts to tame elephants as the “dare theory of domestication” [50]. Captive elephants have never been the subject of sustained breeding programs, nor have they been selected for particular characteristics as has been found with truly domesticated animals. As a result, the genetic makeup of captive elephants has not changed over time. Elephants must be considered captive wild animals [47,48], aside from any evolved changes that might have resulted from their interactions with humans.

One consequence of this situation is that African and Asian elephants are the only “domesticated” species whose survival as a species is at risk.

The management of the Asian elephant is quite anomalous in the conservation world, … compared to other large mammals. Elephas maximus Linn., 1758, an endangered species listed in Appendix I of CITES… number between 37,000 and 48,000 animals in the wild. Scattered through thirteen countries, the wild elephant is nearly everywhere severely threatened by habitat destruction, poaching, and fragmentation into small, isolated groups… nowhere in Asia is there a single wild population large enough to avoid inbreeding. Of the two large captive groups outside of Asia, the population in European zoos and circuses is essentially moribund with most cows too old to breed, while the North American population is far from self-sustaining at a time when both law and public opinion make it ever harder to keep elephants [47].

An important issue from the perspective of this paper is that the relationship between humans and elephants probably comes closer to commensal than any other I discuss because it is not easy to see what benefits the elephants receive. Elephants are potentially dangerous. In North America, more zoo and circus keepers are killed annually by elephants than by all other animals combined, a great irony considering that the public usually sees the elephant as a placid, kindly herbivore [47]. Keeping elephants means that human deaths are unavoidable. Traditional skills of elephant management are easily lost; however, elephant temperament seems unlikely to change.

Elephants clearly have individual temperaments or personalities and have been described by their keepers, whether Asians or Westerners, as everything from saints to killers, whether in their behavior towards humans or even towards other elephants [50]. It is important to match the unique behavior of each elephant to each mahout. Assigning the wrong rider can ruin a good elephant; putting the wrong mahout atop the wrong elephant can easily get him killed. “I have known the training of a previously well-behaved animal to be lost to such a degree that she would endure neither load nor rider, simply owing to the accident of being placed in the charge of an irascible, fitful keeper, who first negligently indulged, and then wantonly punished her” [47]. These results reveal the logic behind the “dare theory” of domestication [50].

To further complicate the situation, other scholars have raised the question as to whether African elephants might be considered self-domesticating [51]. Asian elephants were captured from the wild and used in captivity because of a human need for large, strong animals to assist with a number of activities. Elephants found in captivity and in the wild are genetically indistinguishable [52]. As I have discussed, domestication is a multigenerational process spanning many consecutive events of selective breeding toward reduced aggression, which has never been shown to have occurred systematically in any elephant species. All currently existing elephant species diverged from a common ancestor in the last seven million years [52], yet all show similar features that some scholars associate with self-domestication.

Cross-species comparison of cognitive, behavioral, and physiological traits suggests that elephants may have indeed undergone at least a partial process of self-domestication. Domestication syndrome is associated with selection and overrepresentation in known genes; therefore, elephants should display selection and enrichment in at least some of these traits. Genes that have been positively selected in African elephants are enriched in pathways involved in domestication, and several candidate genes associated with domestication have been positively selected in African elephants [51].

In line with the self-domestication hypothesis, elephants generally exhibit low levels of aggression, with intraspecific and interspecific violence being relatively uncommon. Even during musth, a periodic condition in which male elephants display elevated aggression and a spike in testosterone levels, male-on-male injury and mortality are relatively rare. Males emit warning vocalizations and chemical signals that communicate their state and warn others from engaging with them. Elephants are socially tolerant and work to mitigate conflict, although this varies with rank and affiliation [53,54]. The interesting thing is that elephants are so inclined towards cooperation that when they are treated kindly, they form strong cross-species bonds with their human attendants, who bathe, feed, and care for them. Under such circumstances, the relationship becomes mutualistic. I have also observed strong social bonds between African and Asian elephants when they are housed together. In the Topeka Zoo, an older Asian elephant often showed rocking behavior, which is a means of coping with stress. When she did this, her African elephant companion would come over and place her trunk over the older elephant’s neck, which seemed to calm her down.

Elephants desire social contact, so if their primary social bond is with a human who is gentle and respectful, they will treat that individual well in turn. Elephants have Von Economo neurons (VEN) in their cerebral cortex, which are associated with special cognitive abilities, empathy, and self-awareness [55]. These genes are suggested to reflect a specialization for the transmission of social information. In addition, elephants’ cortisol levels (a biomarker of reactive aggression) are sensitive to changes in the social environment, another distinctive feature of domestication. Their prolonged development and dependence on parental care impact learning by giving rise to more learning opportunities through culture, imitation, and exposure—as opposed to innate knowledge—which in turn facilitate the acquisition of richer behaviors. Indeed, research shows that much of the wild elephant’s behavioral repertoire is socially transmitted [54,56]. Elephants display an impressive capacity for short- and long-range communication and rely on a rich multimodal sensory system that includes vocal, visual, tactile, and chemical signals [56], which reveals a high degree of intraspecific variation both within and between individuals and across different groups of elephants [57,58].

The link between mutualism and domestication in elephants is more problematic than with the carnivores for several reasons. First, most scholars in this field state unequivocally that elephants are not domestic but “tamed”. Zeder refers to elephants as “tame captives”.

In some ways, these animals qualify as domesticates in that they are engaged in a sustained, multigenerational relationship with humans, in which humans assume considerable control over their movement, feeding, and protection to extract specific resources… since they are not bred in captivity, the normal array of selective factors responsible for creating domestic genotypes in other animal domesticates never come into play…, the process of domestication begins anew with each animal tamed [11], p. 177.

Second, the issue of self-domestication is open to question because this idea remains somewhat controversial. Even those who endorse this idea make the point that “it is not clear whether some of the criteria associated with self-domestication (e.g., extended juvenile period, rareness of infanticide) cannot also be associated with increased prosociality alone” [51], p. 8. Finally, benefits to the elephants seem minor [47,48,59]. Even though the elephants themselves are capable of forming strong bonds with humans, they are the primary contributors to the relationship, basically trading labor for companionship and grooming.

In this last sense, elephants are not all that different from the generally accepted group of domestic species, i.e., ungulates that are cared for by humans, which are used for food (including milk), fiber, and hides, while some also provide labor [9,11]. These include various bovids (cattle, yaks, water buffalo, goats, sheep), camels, pigs, and equids (horses, donkeys). All of these have been modified to some degree during their coexistence with humans, and some are modified to a much greater extent than others, i.e., cattle and sheep, whereas others have been barely modified at all, e.g., water buffalo and camels. These are animals considered to have been domesticated through the prey pathway identified by Zeder [11], i.e., animals that were originally hunted but subsequently became domesticated, like cattle, goats, and sheep [9].

The final pathway to domestication described by Zeder is called directed, in which humans identified animals that would be useful primarily as beasts of burden and rarely used for food, and horses, donkeys, and camels are considered to be examples of this type of relationship. Directed species were among the last to be domesticated, i.e., within the last 3000–4000 years, when humans became involved in extensive trade and needed something more than cattle-drawn carts as beasts of burden [9]. Some try to put elephants in this last group, largely because they have only been “tamed” in the last 3000–4000 years, but they are clearly less altered from their wild forms and cannot be bred in captivity.

To me, the problem is that the prey and directed pathways overlap more than is comfortable. Yaks, cattle, and especially water buffalo can readily serve as beasts of burden, whereas horses and perhaps donkeys and camels were originally hunted for food. Finally, there are species like reindeer, which are used for meat, milk, and hides and also serve as beasts of burden for various peoples in northern Asia.

Virtually all of the species in the prey and directed pathways have developed (evolved) mutualistic relationships with humans after they have become domesticated because they depend on humans for food, shelter, and protection from predators. Even domestic cats and small domestic dogs also depend on humans for these. In addition, all of these domestic species have become much more abundant under domestication than they were in the wild. World populations of these species often number in the hundreds of millions (dogs and cats, cattle, sheep and goats, pigs) [60]. Thus, there is a demographic benefit to becoming domesticated, with some favored breeders having phenomenal levels of direct fitness. Ironically, elephants are the clearest example of a species that was once ecologically dominant and is threatened with extinction in our contemporary world. This, if anything, establishes that they are not truly domesticated. No truly domesticated species is even close to extinction, although their ancestors may be rare in the wild (Tahki (Przewalksi’s horse), wild asses, wolves, dingoes, and European wildcats).

4. Final Conclusions

What is revealed in this paper is that the term domesticated is being used as a catchall for a wide range of species interactions, including several that seem to be obviously mutualistic in nature. This, in turn, makes the term human/wildlife mutualism somewhat arbitrary, as it depends on what definition or category of domestication an investigator employs. Some species, e.g., elephants and dingoes, are not considered to be domestic animals, yet are often considered as domesticated. The term self-domestication is being used loosely and only sows further confusion, especially with regard to the status of elephants. Finally, species that have benefitted from human interactions from their inception, like dingoes, wolves, and wildcats, should be discussed in terms of mutualism rather than commensalism to describe the origin of these relationships [12,22].