RESUMO
Climatic models predict scenarios in which ambient temperature will continue increasing worldwide. Under these climatic conditions, fitness and animal welfare of many populations are expected to suffer, especially those that live in captive or semi-natural conditions, where opportunities of heat abatement are limited. We undertook an experimental design to assess the effect of heat abatement that water sprinkling might have on Iberian red deer calf growth and behaviour from birth to weaning (135 days). One group of ten mother-calf pairs lived on plots with water sprinkling (treatment) available during summer's hottest time of the day, while the control group (nine mother-calf pairs) occupied plots with no available water sprinkling. Treatment and control groups were fed ad libitum and swapped between plots every seven days to minimise any plot effect. Body weight was monitored weekly and individual behaviour was recorded once or twice a week at mid-day. We observed that calves had showers under the sprinklers and wallowed in mud puddles. The results clearly indicated that calves of the treatment group showed a significant increase in body weight at weaning in comparison with the control group, with no differences between sexes (treatment: male = 56.5 kg, female = 50.3 kg; control: male = 50.3 kg, female = 46.5 kg). Mother weight and mother age effects were negligible on calf body weight at weaning. The heavier the mother the faster was the rate of growth of its offspring, irrespective of calf sex. The model indicated that although males grew significantly slower than female calves in the control group, males grew faster than females when exposed to the treatment. Calves of the treatment group spent less time drinking, less time in the shade, similar time eating and more time in motion than calves of the control group. There were no behavioural differences between calf sexes of treatment and control groups. The results indicate the importance of providing animals with opportunities of heat abatement in hot environments to improve animal growth and welfare in farmed Iberian red deer.
Assuntos
Cervos/crescimento & desenvolvimento , Cervos/psicologia , Água/administração & dosagem , Animais , Animais Domésticos/crescimento & desenvolvimento , Animais Domésticos/psicologia , Comportamento Animal , Peso Corporal , Feminino , Temperatura Alta , Masculino , DesmameAssuntos
Animais Domésticos , Ansiedade , Depressão , Interação Humano-Animal , Cuidados Paliativos , Assistência Terminal , Animais , Cães , Feminino , Masculino , Terapia Assistida com Animais , Animais Domésticos/psicologia , Ansiedade/terapia , Transtornos de Ansiedade/terapia , Depressão/terapia , Transtorno Depressivo/terapia , Propriedade , Cuidados Paliativos/métodos , Cuidados Paliativos/psicologia , Animais de Estimação , Fatores Sexuais , HumanosRESUMO
This article draws on a more-than-representational approach to reconsider how geographers engage with ideas of 'health'. Health can be understood as the constant reshaping of an individual's capacity to affect and be affected, the way in which a body's powers to act are dynamically augmented or diminished by different affective relations. The article also addresses calls for health geography to engage with the more-than-human. The article mobilises a qualitative study of 'care farming' within England and Wales to highlight the generative potential of human-animal relations in (re)shaping the diverse affective relations gathered together to produce new bodily capacities. The article demonstrates how animal presence and agency can break down barriers, allowing people to navigate and negotiate adverse contexts and access support in a manner and space in which they feel comfortable. Additionally, human-animal relations are shown to produce affective experiences that act to re-place identities, understandings, and ways of 'being-with' the world that can enact what different actants may become. Human-animal relations matter for health.
Assuntos
Agricultura/métodos , Animais Domésticos/psicologia , Nível de Saúde , Animais , Inglaterra , Geografia , Humanos , Entrevistas como Assunto/métodos , Pesquisa Qualitativa , Pensamento , País de GalesRESUMO
The great increase in the study of dog cognition in the current century has yielded insights into canine cognition in a variety of domains. In this review, we seek to place our enhanced understanding of canine cognition into context. We argue that in order to assess dog cognition, we need to regard dogs from three different perspectives: phylogenetically, as carnivoran and specifically a canid; ecologically, as social, cursorial hunters; and anthropogenically, as a domestic animal. A principled understanding of canine cognition should therefore involve comparing dogs' cognition with that of other carnivorans, other social hunters, and other domestic animals. This paper contrasts dog cognition with what is known about cognition in species that fit into these three categories, with a particular emphasis on wolves, cats, spotted hyenas, chimpanzees, dolphins, horses, and pigeons. We cover sensory cognition, physical cognition, spatial cognition, social cognition, and self-awareness. Although the comparisons are incomplete, because of the limited range of studies of some of the other relevant species, we conclude that dog cognition is influenced by the membership of all three of these groups, and taking all three groups into account, dog cognition does not look exceptional.
Assuntos
Animais Domésticos/psicologia , Carnívoros/psicologia , Cognição , Cães/psicologia , Psicologia Comparada , Comportamento Social , AnimaisRESUMO
This study examines the impact of ethical attitude on the willingness to pay for farm animal welfare improvement in Germany. Little is known about the pluralism of moral attitudes that may exist behind farm animal welfare issues and its relationship to customers' willingness to pay for it. Via a large survey (n = 1334) we are able to identify different moral dimensions by employing validated scales. We find utilitarian alongside deontological attitudes as well as a mixture of both. Thus, presupposing a standard moral attitude is too simple. This has implications for decision-making on markets, since the implicit normative assumptions of a utilitarian position in economics has to be critically assessed. Furthermore, we asked for the willingness to pay for various aspects of farm animal welfare improvement. We find significant positive correlations between willingness to pay and environmental concern, altruism and less apathy. Measured in Euro, a higher environmental concern has the strongest effect on WTP for all five moral scales. Outliers with higher bids are willing to pay almost five times for any aspect of farm animal welfare than the rest of the sample. A more detailed analysis of outliers demonstrates that market-based approaches have restrictions in capturing certain moral values. Moreover, the motivations behind zero bids reveal that moral concerns outweigh indifference towards animal welfare by far. This has implications how policy can be designed to serve people's demand for higher animal welfare standards. Two other findings are of interest. First, we find a very high number of people assigning an intrinsic value to animals (90%). Second, zero bids and outlier treatment in WTP-studies deserves more careful consideration, since WTP-estimates are easily skewed by excluding these groups.
Assuntos
Criação de Animais Domésticos/economia , Bem-Estar do Animal/economia , Animais Domésticos , Atitude , Comportamento do Consumidor , Princípios Morais , Adolescente , Adulto , Idoso , Animais , Animais Domésticos/psicologia , Tomada de Decisões , Meio Ambiente , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Psicológicos , Plantas , Adulto JovemRESUMO
Domesticated animals such as dogs and laboratory mice show a high level of tameness, which is important for humans to handle them easily. Tameness has two behavioral components: a reluctance to avoid humans (passive tameness) and a motivation to approach humans (active tameness). To quantify these components in mice, we previously developed behavioral tests for active tameness, passive tameness, and the willingness to stay on a human hand, each designed to be completed within 3 min. The data obtained were used for selective breeding, with a large number of mice analyzed per generation. The active tameness test measures the movement of the mouse toward a human hand and the contact it engages in. The passive tameness test measures the duration of time that a mouse tolerates human touch. In the stay-on-hand test, a mouse is placed on a human hand and touched slowly using the thumb of that hand; the duration of time that the animal remains on the hand is measured. Here, we describe the test set-up and apparatus, explain the procedures, and discuss the appropriate data analysis. Finally, we explain how to interpret the results.
Assuntos
Animais Domésticos/psicologia , Comportamento Animal/fisiologia , Animais , Masculino , CamundongosRESUMO
The domestication of animals and plants offers an exceptional opportunity to study evolutionary adaptations. In particular, domesticated animals display several behavioral alterations, including increased sociability and decreased fearfulness and aggression, when compared with their wild ancestors. However, studies quantifying simultaneous changes in multiple behaviors during domestication are lacking. Moreover, the role of human-directed play behavior has been largely neglected when studying the domestication process. Here we address these issues by examining behavioral changes during the domestication of the dog (Canis familiaris) from the gray wolf (Canis lupus) using a standardized behavioral test applied to wolf hybrids and several dog breeds. Contrary to expectations, our study provides little support for collective behavioral alterations. Specifically, although we found that wolf hybrids were less playful and overall more fearful than dogs, we did not detect any differences in sociability or aggression between wolf hybrids and dog breeds. Instead, our results suggest that behavioral alterations during domestication do not necessarily occur in concert and point to an important, but previously overlooked, role of selection on play behavior directed at humans during the domestication of dogs. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Assuntos
Animais Domésticos/psicologia , Comportamento Animal/fisiologia , Cães/psicologia , Domesticação , Comportamento Social , Lobos/psicologia , Animais , HumanosRESUMO
Seeking a scientific basis for understanding and treating mental illness, and inspired by the work of Ivan Pavlov, American physiologists, psychiatrists and psychologists in the 1920s turned to nonhuman animals. This paper examines how new constructs such as "experimental neurosis" emerged as tools to enable psychiatric comparison across species. From 1923 to 1962, the Cornell "Behavior Farm" was a leading interdisciplinary research center pioneering novel techniques to experimentally study nonhuman psychopathology. Led by the psychobiologist Howard Liddell, work at the Behavior Farm formed part of an ambitious program to develop new preventative and therapeutic techniques and bring psychiatry into closer relations with physiology and medicine. At the heart of Liddell's activities were a range of nonhuman animals, including pigs, sheep, goats and dogs, each serving as a proxy for human patients. We examine how Pavlov's conceptualization of 'experimental neurosis' was used by Liddell to facilitate comparison across species and communication between researchers and clinicians. Our close reading of his experimental system demonstrates how unexpected animal behaviors and emotions were transformed into experimental virtues. However, to successfully translate such behaviors from the animal laboratory into the field of human psychopathology, Liddell increasingly reached beyond, and, in effect, redefined, the Pavlovian method to make it compatible and compliant with an ethological approach to the animal laboratory. We show how the resultant Behavior Farm served as a productive "hybrid" place, containing elements of experiment and observation, laboratory and field. It was through the building of close and more naturalistic relationships with animals over extended periods of time, both normal and pathological, and within and outside of the experimental space, that Liddell could understand, manage, and make useful the myriad behavioral complexities that emerged from the life histories of experimental animals, the researchers who worked with them, and their shared relationships to the wider physical and social environments.
Assuntos
Animais Domésticos/psicologia , Modelos Animais de Doenças , Psicopatologia/história , Animais , Comportamento Animal , História do Século XX , Humanos , Psicopatologia/métodosRESUMO
The aim of the present study was to describe the suckling behavior of the offspring of farmed European fallow deer Dama dama in the postnatal period. Video surveillance footage from the first 18 days postpartum was analyzed in detail to reveal that the duration of interactions between the mother and the offspring changed with the fawns' age. The duration of mother-offspring interactions was longest between postpartum days 12 and 18. The frequency of interactions at different times of the day varied in the analyzed periods. The results of the study could be used to increase the welfare of farmed deer.
Assuntos
Animais Domésticos/psicologia , Animais Recém-Nascidos/psicologia , Animais Lactentes/psicologia , Cervos/psicologia , Comportamento de Sucção/fisiologia , Fatores Etários , Bem-Estar do Animal , Animais , Feminino , MasculinoRESUMO
Exposure to certain natural stimuli improves people's moods, reduces stress, enhances stress resilience, and promotes mental and physical health. Laboratory studies and real estate prices also reveal that humans prefer environments containing a broad range of natural stimuli. Potential mediators of these outcomes include: 1) therapeutic effects of specific natural products; 2) positive affective responses to stimuli that signalled safety and resources to our evolutionary ancestors; 3) attraction to environments that satisfy innate needs to explore and understand; and 4) ease of sensory processing, due to the stimuli's "evolutionary familiarity" and/or their fractal, self-repeating properties. These processes, and the benefits humans gain from natural stimuli, seem to be largely innate. They thus have strong implications for other species (including laboratory, farm and zoo animals living in environments devoid of natural stimuli), suggesting that they too may have nature-related "sensory needs". By promoting positive affect and stress resilience, preferred natural stimuli (including views, sounds and odours) could therefore potentially provide effective and efficient ways to improve captive animal well-being.
Assuntos
Emoções , Meio Ambiente , Saúde Mental , Estresse Fisiológico/fisiologia , Animais , Animais Domésticos/fisiologia , Animais Domésticos/psicologia , Animais de Zoológico/fisiologia , Animais de Zoológico/psicologia , Humanos , InstintoRESUMO
Studies of animal personality attempt to uncover underlying or "latent" personality traits that explain broad patterns of behaviour, often by applying latent variable statistical models (e.g., factor analysis) to multivariate data sets. Two integral, but infrequently confirmed, assumptions of latent variable models in animal personality are: i) behavioural variables are independent (i.e., uncorrelated) conditional on the latent personality traits they reflect (local independence), and ii) personality traits are associated with behavioural variables in the same way across individuals or groups of individuals (measurement invariance). We tested these assumptions using observations of aggression in four age classes (4-10 months, 10 months-3 years, 3-6 years, over 6 years) of male and female shelter dogs (N = 4,743) in 11 different contexts. A structural equation model supported the hypothesis of two positively correlated personality traits underlying aggression across contexts: aggressiveness towards people and aggressiveness towards dogs (comparative fit index: 0.96; Tucker-Lewis index: 0.95; root mean square error of approximation: 0.03). Aggression across contexts was moderately repeatable (towards people: intraclass correlation coefficient (ICC) = 0.479; towards dogs: ICC = 0.303). However, certain contexts related to aggressiveness towards people (but not dogs) shared significant residual relationships unaccounted for by latent levels of aggressiveness. Furthermore, aggressiveness towards people and dogs in different contexts interacted with sex and age. Thus, sex and age differences in displays of aggression were not simple functions of underlying aggressiveness. Our results illustrate that the robustness of traits in latent variable models must be critically assessed before making conclusions about the effects of, or factors influencing, animal personality. Our findings are of concern because inaccurate "aggressive personality" trait attributions can be costly to dogs, recipients of aggression and society in general.
Assuntos
Agressão , Animais Domésticos/psicologia , Comportamento Animal/fisiologia , Cães/psicologia , Fatores Etários , Envelhecimento/psicologia , Animais , Teorema de Bayes , Feminino , Humanos , Masculino , PersonalidadeRESUMO
Hybridization between domestic and wild species is known to widely occur and it is reported to be one of the major causes of the current biodiversity crisis. Despite this, poor attention has been deserved to the behavioural ecology of hybrids, in particular in relation to their social behaviour. We carried out a camera trap study to assess whether phenotypically anomalous colouration in wild boar, i.e. potentially introgressed with domestic pigs, affected the hierarchical structure of wild boar social groups. Chromatically anomalous wild boars (CAWs) were detected in 32 out of 531 wild boar videos. In most videos (75%) CAWs were the latest of the group, independently from their age class and group composition. Aggressions by their wild type fellows were recorded in 31.25% videos; by contrast, no aggression among wild type individuals was observed. The lack of camouflage may expose CAWs, and thus their group, to a higher predation risk, compared to wild type groups. This individual loss of local adaptation may increase predation risk by the wolf or detection by hunters, being maladaptive for the whole social group.
Assuntos
Animais Domésticos/psicologia , Sus scrofa/psicologia , Suínos/psicologia , Agressão , Animais , Hibridização Genética , Pigmentação da Pele , Comportamento SocialRESUMO
A questionnaire instrument for obtaining quantitative behavioral evaluations of pet cats from cat owners was developed and validated. Exploratory Factor Analysis of 2608 questionnaire responses to 149 behavioral questions/items extracted a total of 23 distinct factors that measured most of the more common dimensions of cat behavior. Seventeen of the 23 factors demonstrated adequate-high internal reliability (Cronbach's alpha=0.712-0.923). Questionnaire validation was accomplished by determining: (a) whether owners' subjective ratings of the severity of their cat's behavior problems were associated with cats' actual scores on expected questionnaire factors, (b) whether expected associations between specific demographic and/or lifestyle characteristics and behavior were confirmed by cats' factor or item scores on the questionnaire, and (c) whether breed rankings based on owner-reported factor scores matched those previously derived from the opinions of experts (veterinarians). The results of these various tests confirmed the overall construct validity of the questionnaire.
Assuntos
Animais Domésticos/psicologia , Comportamento Animal/fisiologia , Animais , Gatos , Feminino , Humanos , Reprodutibilidade dos Testes , Inquéritos e QuestionáriosRESUMO
When learning from others, human children tend to faithfully copy - or 'overimitate' - the actions of a demonstrator, even when these actions are irrelevant for solving the task at hand. We investigate whether domesticated dogs (Canis familiaris) and dingoes (Canis dingo) share this tendency to overimitate in three experiments. In Experiment 1, dogs and dingoes had the opportunity to solve a puzzle after watching an ostensive demonstrator who used both a relevant action and an irrelevant action. We find clear evidence against overimitation in both species. In contrast to human children (Horner & Whiten, 2005), dogs and dingoes used the irrelevant action less often across trials, suggesting that both species were filtering out the irrelevant action as they gained experience with the puzzle (like chimpanzees; Horner & Whiten, 2005). Experiments 2 and 3 provide further evidence against overimitation, demonstrating that both species' behavior is better characterized by individual exploration than overimitation. Given that both species, particularly dogs, show human-like social learning in other contexts, these findings provide additional evidence that overimitation may be a unique aspect of human social learning. A video abstract of this article can be viewed at: https://youtu.be/g2mRniJZ7aU.
Assuntos
Comportamento Imitativo , Aprendizado Social , Animais , Animais Domésticos/psicologia , Animais Selvagens/psicologia , Comportamento Animal , Evolução Biológica , Criança , Comportamento Infantil , Cães , HumanosRESUMO
This paper will argue that understanding animal welfare and the individual vulnerability to stress-related disease requires a fundamental understanding of functional individual variation as it occurs in nature as well as the underlying neurobiology and neuroendocrinology. Ecological studies in feral populations of mice, fish, and birds start to recognize the functional significance of phenotypes that individually differ in their behavioral and neuroendocrine response to environmental challenge. Recent studies indicate that the individual variation within a species may buffer the species for strong fluctuations in the natural habitat. Similarly, evolutionary ancient behavioral trait characteristics have now been identified in a range of domestic farm animals including cattle, pigs, and horses. Individual variation in behavior can be summarized in a 3-dimensional model with coping style, emotionality, and sociality as independent dimensions. These dimensions can be considered trait characteristics that are stable over time and across situations within the individual. This conceptual model has several consequences. First, the coping style dimension is strongly associated with differential stress vulnerability. Social stress studies show that proactive individuals are resilient under stable environmental conditions but vulnerable when outcome expectancies are violated. Reactive individuals are, in fact, rather flexible and seem to adapt more easily to a changing environment. A second consequence relates to genetics and breeding. Genetic selection for one trait usually implies selection for other traits as well. It is discussed that a more balanced breeding program that takes into account biologically functional temperamental traits will lead to more robust domestic farm animals. Finally, the relationship between temperamental traits, animal production, fitness, and welfare is discussed.
Assuntos
Criação de Animais Domésticos/métodos , Bem-Estar do Animal , Animais Domésticos/psicologia , Comportamento Animal/fisiologia , Abrigo para Animais , Estresse Psicológico , Adaptação Psicológica , Animais , Animais Domésticos/fisiologia , Evolução Biológica , Meio Ambiente , Fazendas , PersonalidadeRESUMO
Animals are "in" - since prehistoric times when humans (or their ancient ancestors) were hunting animals, and when they fabricated the Paleolithic dog as well as the Paleolithic cat. In less general terms, animals are "in" since they received names and were listed, observed, mummified, turned into totems, and, later on, dissected, tortured under laboratory conditions, trained as experimental subjects or "purified" as model organisms. And they are massively "in" again, but now from overtly legal and moral points of view, at least since the last two decades of the twentieth century. This is to say that modern members of the species Homo sapiens have always been connected to animals of the most various kinds - from the human flea (Pulex irritans) and the cat flea (Ctenocephalides felis) to marine mammals, such as dolphins and whales, from horses to parrots, from scallops to worms, and so on.
Assuntos
Animais Domésticos/psicologia , Animais Selvagens/psicologia , Vínculo Humano-Animal , Animais , HumanosRESUMO
The domestic dog shows a wide range of morphologies, that humans have selected for in the process of creating unique breeds. Recent studies have revealed correlations between changes in morphology and behaviour as reported by owners. For example, as height and weight decrease, many undesirable behaviours (non-social fear, hyperactivity and attention seeking) become more apparent. The current study aimed to explore more of these correlations, but this time used reports from trained observers. Phenotypic measurements were recorded from a range of common dog breeds (n = 45) and included cephalic index (CI: the ratio of skull width to skull length), bodyweight, height and sex. These data were then correlated with results from the Dog Mentality Assessment (DMA), which involves trained observers scoring a dog's reaction to stimuli presented over 10 standardised subtests. Each subtest is designed to evoke a behavioural response. Backward elimination and weighted step-wise regression revealed that shorter dogs demonstrated more aggressive tendencies, reacting defensively toward both assistants dressed as ghosts (p = 0.045), and to a dummy (p = 0.008). Taller dogs were more affectionate when greeting and being handled by humans (p = 0.007, p = <0.001, respectively). Taller dogs were also more cooperative (p = <0.001), and playful (p = 0.001) with humans than shorter dogs. Heavier dogs were more inquisitive toward a dummy (p = 0.011), to the source of a metallic noise (p = 0.010) and to an assistant (p = 0.003). Heavier dogs were also more attentive to the ghosts (p = 0.013). In comparison, lighter dogs were cautious of a dummy (p = <0.001) and fearful of the sound of a gunshot (p = <0.001). Lighter dogs were also cautious of, and demonstrated prolonged fearfulness toward, the source of metallic noise (p = <0.001, p = <0.034, respectively). With a far larger sample and the advantage of third-party reporting (which overcomes potential owner bias), the current findings build on previous studies in this field, further supporting covariance between morphology and behaviour.
Assuntos
Animais Domésticos/anatomia & histologia , Animais Domésticos/psicologia , Comportamento Animal/fisiologia , Cabeça/anatomia & histologia , Animais , Atenção/fisiologia , Cães , Medo/fisiologia , Feminino , MasculinoRESUMO
What does domestication select for in terms of foraging and anti-predator behaviors? We applied principles of patch use and foraging theory to test foraging strategies and fear responses of three strains of Mus musculus: wild-caught, control laboratory, and genetically modified strains. Foraging choices were quantified using giving-up densities (GUDs) under three foraging scenarios: (1) patches varying in microhabitat (covered versus open), and initial resource density (low versus high); (2) daily variation in auditory cues (aerial predators and control calls); (3) patches with varying seed aggregations. Overall, both domestic strains harvested significantly more food than wild mice. Each strain revealed a significant preference for foraging under cover compared to the open, and predator calls had no detectable effects on foraging. Both domestic strains biased their harvest toward high quality patches; wild mice did not. In terms of exploiting favorable and avoiding unfavorable distributions of seeds within patches, the lab strain performed best, the wild strain worst, and the mutant strain in between. Our study provides support for hypothesis that domestic animals have more energy-efficient foraging strategies than their wild counterparts, but retain residual fear responses. Furthermore, patch-use studies can reveal the aptitudes and priorities of both domestic and wild animals.
Assuntos
Animais Domésticos/psicologia , Animais Selvagens/psicologia , Comportamento Alimentar/psicologia , Comportamento Predatório/fisiologia , Animais , Animais Domésticos/fisiologia , Animais Selvagens/fisiologia , Comportamento de Escolha , Sinais (Psicologia) , Ecossistema , Medo/fisiologia , Comportamento Alimentar/fisiologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL/fisiologiaRESUMO
Habituation to humans was an essential component of horse (Equus caballus ferus) domestication, with the nondomestication of zebras (Equus quagga) possibly reflecting an adaptive constraint on habituation. We present the human hunting hypothesis, arguing that ancestral humans hunted African animals, including zebras, long enough to promote a persistent wariness of humans, whereas a briefer period of hunting horses in Central Asia influenced by glacial cycles was unlikely to produce an equally persistent wariness. An alternative habituation to humans hypothesis, prompted by field observations, posits that zebras can habituate well to nonthreatening humans given sufficient exposure. If so, other factors must account for zebra nondomestication. To examine these hypotheses, we compared the flight initiation distances (FIDs) of wild horses in the United States and plains zebras in Africa to a human approaching on foot (N = 87). We compared the flight behavior of both species at sites with low and high exposure to humans (mean humans/acre = .004 and .209, respectively). Analyses revealed a significant interaction (p = .0001) between equid species and level of human exposure. The mean FIDs of horses (146 m) and zebras (105 m) with low human exposure did not differ appreciably (p = .412), but these distances were substantially longer (p < .0001) than those of horses (17 m) and zebras (37 m) with high human exposure that did differ significantly (p < .0001). The finding that plains zebras habituate less completely to humans than horses do might reflect an adaptive response to historical hunting and partly explain their resistance to domestication.