Michael Mendl

Michael Mendl
University of Bristol | UB · School of Veterinary Sciences

PhD in Animal Behaviour

About

228
Publications
50,183
Reads
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11,083
Citations
Introduction
I work on animal behaviour, emotion, cognition and welfare. Our work spans from fundamental underpinning studies of animal welfare, especially the study of animal emotion and the development of new methods for assessing these states, to more applied research on the behaviour and welfare of farm, companion, lab and zoo animals.
Additional affiliations
January 1997 - April 2020
University of Bristol
Position
  • Professor
March 1993 - December 1996
Scottish Agricultural College
Position
  • Behavioural Physiologist
April 1988 - March 1993
University of Cambridge
Education
October 1982 - May 1986
University of Cambridge
Field of study
  • Zoology
October 1979 - July 1982
University of Cambridge
Field of study
  • Natural Sciences (Biological)

Publications

Publications (228)
Article
Full-text available
Our experiences of the conscious mental states that we call emotions drive our interest in whether such states also exist in other animals. Because linguistic report can be used as a gold standard (albeit indirect) indicator of subjective emotional feelings in humans but not other species, how can we investigate animal emotions and what exactly do...
Article
Full-text available
Background: Pet care guidelines play an important role in ensuring that owners are well informed about good husbandry practices, allowing them to provide the best care for their animals. However, the development of such guidelines is difficult when there is little appropriate empirical evidence on which to base guidelines, as in the case of pet ra...
Article
Biomedical research suffers from a crisis of reproducibility and translatability (1), with some studies estimating that more than 50% of preclinical studies are irreproducible (2). The lack of reproducible results has led to annual economic losses of about US$28 billion in the United States alone, delays to new treatments, and unneces- sary use of...
Article
Full-text available
Human patients with chronic pain from osteoarthritis often report impaired sleep, but it is not yet known if sleep is also impaired in dogs with osteoarthritis. This study aimed to compare the night-time sleep behaviour of osteoarthritic (N=20) and healthy control (N=21) dogs over a 28-day period, using an actigraphic device (the FitBark activity m...
Article
Reporting of outcome variables by care-givers in welfare studies is commonplace, but is open to subjective bias and so requires validation. Biases can occur in either direction: familiarity with an animal allows a deeper insight into welfare problems, but also can lead to reticence in admitting that an animal in one's care is experiencing problems....
Article
To assess the welfare of captive animals, validated measures, so-called ‘welfare indicators’, are required. We used a triangulation approach to investigate the extent to which different measures converged to provide corroborating evidence of welfare. Laying hens were exposed to living conditions designed to be generally preferred (GP) or generally...
Article
Background: There are few studies on the physiology and haematology of rescued bearded capuchin monkeys. These are necessary to better understand the health and welfare status of the animals, including when performing reintroductions, and to avoid zoonoses. Methods: We aimed to obtain physiological and haematological values, morphometry and para...
Article
We previously identified in laboratory mice an inactive state [being awake with eyes open motionless within the home cage; inactive but awake, ‘IBA’] sharing etiological factors and symptoms with human clinical depression. We further test the hypothesis that greater time spent displaying IBA indicates a depression-like state in mice by investigatin...
Article
Surveys provide a low-cost means to obtain large amounts of data that are ideal for conducting exploratory research, and they are becoming an increasingly valuable tool in a veterinary context. We investigated whether surveys of pet rat owners might provide useful data that could pave the way for more targeted empirical studies of pet and laborator...
Article
Full-text available
A top priority of modern zoos is to ensure good animal welfare (AW), thus, efforts towards improving AW monitoring are increasing. Welfare assessments are performed through more traditional approaches by employing direct observations and time-consuming data collection that require trained specialists. These limitations may be overcome through autom...
Article
Understanding why some species thrive in captivity, while others struggle to adjust, can suggest new ways to improve animal care. Approximately half of all Psittaciformes, a highly threatened order, live in zoos, breeding centres and private homes. Here, some species are prone to behavioural and reproductive problems that raise conservation and eth...
Article
Full-text available
Domestic dogs are trained using a range of different methods, broadly categorised as reward based (positive reinforcement/negative punishment) and aversive based (positive punishment/negative reinforcement). Previous research has suggested associations between use of positive punishment-based techniques and undesired behaviours, but there is little...
Article
Third-party interventions may regulate conflicts to reduce aggression and promote cohesion amongst group members, but are rarely documented in ungulates. The white-lipped peccary (Tayassu pecari) lives in mixed-sex herds of hundreds of individuals in Neotropical forests, which are likely to benefit from mechanisms that sustain social cohesiveness....
Article
Good translatability of behavioral measures of affect (emotion) between human and nonhuman animals is core to comparative studies. The judgment bias (JB) task, which measures "optimistic" and "pessimistic" decision-making under ambiguity as indicators of positive and negative affective valence, has been used in both human and nonhuman animals. Howe...
Article
Full-text available
Background: To date, despite the substantial literature investigating how rats prefer to be kept in captivity, no research has been conducted to assess the housing, husbandry and health of pet rats. Methods: To better understand the United Kingdom's pet rat population and the welfare issues they face, we conducted an online survey of pet rat own...
Chapter
Full-text available
This chapter reviews assessing emotions in pigs, specifically focusing on the ways of determining negative and positive mental states. It begins by examining behavioural indicators of emotion such as behavioural tests, qualitative behaviour assessment, vocalisations, play behaviour, defence cascade responses and facial expression and body posture....
Article
Full-text available
Within a species, some individuals are better able to cope with threatening environments than others. Paca (Cuniculus paca) appear resilient to over-hunting by humans, which may be related to the behavioural plasticity shown by this species. To investigate this, we submitted captive pacas to temperament tests designed to assess individual responses...
Article
Full-text available
Links between affective states and risk-taking are often characterised using summary statistics from serial decision-making tasks. However, our understanding of these links, and the utility of decision-making as a marker of affect, needs to accommodate the fact that ongoing (e.g., within-task) experience of rewarding and punishing decision outcomes...
Article
Emotions encompass cognitive and behavioural responses to reward and punishment. Using contests as a case-study, we propose that short-term emotions underpin animals' assessments, decision-making, and behaviour. Equating contest assessments to emotional "appraisals", we describe how contestants appraise more than resource value and outcome probabil...
Article
Variation in executive function and age-related cognitive decline may underlie the emergence of behaviour and welfare problems in dogs. A better understanding of such links, and of dog cognition in general, will be facilitated by the development of cognitive tasks that can be readily implemented, including with publicly-owned dogs that are availabl...
Article
Full-text available
Positive animal emotion (affect) is a key component of good animal welfare [1] and plays an important role in stress-coping and resilience [2]. Methods for reliably inducing and measuring positive affect are critical, but both have been limited in availability. In rats, one promising way of inducing positive affective states is by human-simulated r...
Article
Full-text available
Excessive body mass, i.e., being overweight or obese, is a health concern associated with issues such as reduced fertility and lifespan. Some lemur species are prone to extreme weight gain in captivity, yet others are not. To better understand species- and individual-level effects on susceptibility to captive weight gain, we use two complementary m...
Article
Full-text available
The influence of affective states on decision-making is likely to be complex. Negative states resulting from experience of punishing events have been hypothesised to generate enhanced expectations of future punishment and ‘pessimistic’/risk-averse decisions. However, they may also influence how decision-outcomes are valued. Such influences may furt...
Preprint
Full-text available
Just as happy people see the proverbial glass as half-full, ‘optimistic’ or ‘pessimistic’ responses to ambiguity might also reflect affective states in animals. Judgement bias tests, designed to measure these responses, are an increasingly popular way of assessing animal affect and there is now a substantial, but heterogeneous, literature on their...
Article
Just as happy people see the proverbial glass as half-full, ‘optimistic’ or ‘pessimistic’ responses to ambiguity might also reflect affective states in animals. Judgement bias tests, designed to measure these responses, are an increasingly popular way of assessing animal affect and there is now a substantial, but heterogeneous, literature on their...
Article
Full-text available
Affective states are key determinants of animal welfare. Assessing such states under field conditions is thus an important goal in animal welfare science. The rapid Defence Cascade (DC) response (startle, freeze) to sudden unexpected stimuli is a potential indicator of animal affect; humans and rodents in negative affective states often show potent...
Preprint
Full-text available
Links between affective states and risk-taking are often characterised using summary statistics from serial decision-making tasks. However, our understanding of these links, and the utility of decision-making as a marker of affect, needs to accommodate the fact that ongoing (e.g. within-task) experience of rewarding and punishing decision outcomes...
Article
Individual behavioral differences may influence how animals cope with altered environments. Depending on their behavioral traits, individuals may thus vary in how their health is affected by environmental conditions. We investigated the relationship between individual behavior of free-living golden-headed lion tamarins (Leontopithecus chrysomelas)...
Article
Recent clinical and pre-clinical research suggests that affective biases may play an important role in the development and perpetuation of mood disorders. Studies in animals have also revealed that similar neuropsychological processes can be measured in non-human species using behavioural assays designed to measure biases in learning and memory or...
Data
Graphical abstract summarising principles of affect and decision-making model
Preprint
Food sharing experiments with Eurasian jays have provided some of the most compelling evidence to date for co-operative social cognitive abilities in corvids. Male Eurasian jays have been found to alter their food sharing response in line with the specific satiety of their female partner. However, as food sharing forms part of courtship it may be u...
Article
Full-text available
The scientific study of animal affect (emotion) is an area of growing interest. Whilst research on mechanism and causation has predominated, the study of function is less advanced. This is not due to a lack of hypotheses; in both humans and animals, affective states are frequently proposed to play a pivotal role in coordinating adaptive responses a...
Article
Full-text available
Theory and empirical findings predict that individuals in a negative affective state are more sensitive to unexpected reward loss and less sensitive to unexpected reward gain compared to individuals in a neutral or positive affective state. We explore the use of sensitivity to reward shifts measured during successive contrast tasks as an indicator...
Chapter
This second edition of Mental Health and Well-Being in Animals is fully revised, expanded, and comprehensively updated with the most current knowledge about the full array of mental health issues seen in animals. Written by key opinion leaders, internationally-recognized experts and specialists, it is comprehensive covering basic principles to ment...
Article
Full-text available
Affect-driven cognitive biases can be used as an indicator of affective (emotional) state. Since humans in negative affective states demonstrate greater responses to negatively-valenced stimuli, we investigated putative affect-related bias in mice by monitoring their response to unexpected, task-irrelevant stimuli of different valence. Thirty-one C...
Article
Full-text available
Validated measures of animal affect are crucial to research spanning numerous disciplines. Judgement bias, which assesses decision-making under ambiguity, is a promising measure of animal affect. One way of validating this measure is to administer drugs with affect-altering properties in humans to non-human animals and determine whether the predict...
Article
Full-text available
The componential view of human emotion recognises that affective states comprise conscious, behavioural, physiological, neural and cognitive elements. Although many animals display bodily and behavioural changes consistent with the occurrence of affective states similar to those seen in humans, the question of whether and in which species these are...
Preprint
Full-text available
Validated measures of animal affect are crucial to research spanning a number of disciplines including neuroscience, psychopharmacology, and animal welfare science. Judgement bias, which assesses decision-making under ambiguity, is a promising measure of animal affect. One way of validating this measure is to induce affective states using pharmacol...
Article
Objective: To describe clinically relevant, physiological measurements collected during a 3 hour duration of alfaxalone total intravenous anaesthesia. Study design: Case series. Animals: A total of 112 client-owned middle-aged or older dogs. Methods: Dogs were premedicated with intramuscular acepromazine (0.03 mg kg-1). Anaesthesia was induc...
Article
Full-text available
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
Article
Full-text available
Scientific methods for assessing animal affect, especially affective valence (positivity or negativity), allow us to evaluate animal welfare and the effectiveness of 3Rs Refinements designed to improve wellbeing. Judgement bias tasks measure valence; however, task-training may be lengthy and/or require significant time from researchers. Here we dev...
Article
Background: Assessing the affective state of animals is important for a range of research areas, including neuroscience. The use of cognitive judgement and attention biases to determine affective state has been demonstrated in animals, but approaches to assess mood-congruent biases in memory have yet to become established. New method: We describ...
Article
In man, central sensitisation (CS) contributes to the pain of osteoarthritis (OA). Dogs with spontaneous OA may also exhibit CS. Electrophysiological reflex measurements are more objective than behavioural assessments, and can be used to evaluate CS in preclinical and clinical studies. It was hypothesised that dogs suffering from OA would exhibit e...
Article
Full-text available
Affective states influence decision-making under ambiguity in humans and other animals. Individuals in a negative state tend to interpret ambiguous cues more negatively than individuals in a positive state. We demonstrate that the fruit fly,Drosophila melanogaster, also exhibits state-dependent changes in cue interpretation.Drosophilawere trained o...
Article
Full-text available
In recent years there has been a growing research interest in the field of animal emotion. But there is still little agreement about whether and how the word “emotion” should be defined for use in the context of non-human species. Here, we make a distinction between descriptive and prescriptive definitions. Descriptive definitions delineate the way...
Chapter
This third edition of "Animal Welfare" has 407 pages and is divided into five parts. Part I, Issues, introduces the background and philosophy of the subject. Part II covers problems for animal welfare, starting in chapter 3 with the animal's interactions with its environment. The following four chapters use categories similar to the UK Farm Animal...
Article
Syringomyelia is a common and chronic neurological disorder affecting Cavalier King Charles Spaniels. The condition is putatively painful, but evaluating the affective component of chronic pain in non-human animals is challenging. Here we employed two methods designed to assess animal affect - the judgement bias and reward loss sensitivity tests -...
Article
Full-text available
It is widely recommended to group-house male laboratory mice because they are 'social animals', but male mice do not naturally share territories and aggression can be a serious welfare problem. Even without aggression, not all animals within a group will be in a state of positive welfare. Rather, many male mice may be negatively affected by the str...
Preprint
Full-text available
It is widely recommended to group house male laboratory mice because they are ‘social animals’, but male mice do not naturally share territories and aggression can be a serious welfare problem. Even without aggression, not all animals within a group will be in a state of positive welfare. Rather, many male mice may be negatively affected by the str...
Article
Full-text available
RationaleAffective biases are hypothesised to contribute to the cause and treatment of mood disorders. We have previously found that affective biases, associated with learning and memory, are observed following acute treatments with a range of antidepressant and pro-depressant manipulations. Objective This study aimed to test if similar biases are...
Article
Full-text available
In humans, there is evidence that sensory processing of novel or threatening stimuli is right hemisphere dominated, especially in people experiencing negative affective states. There is also evidence for similar lateralization in a number of non-human animal species. Here we investigate whether this is also the case in domestic cattle that may expe...
Data
Dataset lateralization testing. (XLSX)
Article
Full-text available
We studied the social and cognitive performance of piglets raised pre-weaning either in a conventional system with a sow in a farrowing crate (FC) or in a multi-suckling (MS) system in which 5 sows and their piglets could interact in a more physically enriched and spacious environment. After weaning at 4 weeks of age, 8 groups of 4 litter-mates per...
Conference Paper
In zoological collections, species from the diverse order Carnivora are charismatic and popular. Some of these species typically fare well in captivity, living long, healthy lives, breeding readily, and showing few or no behavioural problems. However, others do not adjust as well, with signs of compromised welfare such as poor reproduction, and abn...
Article
Judgement bias tests of animal affect and hence welfare assume that the animal’s responses to ambiguous stimuli, which may herald positive or negative outcomes, are under instrumental control and reflect ‘optimism’ or ‘pessimism’ about what will happen. However, Pavlovian control favours responses (e.g. approach or withdrawal) according to the vale...
Article
Full-text available
Many corvid species accurately remember the locations where they have seen others cache food, allowing them to pilfer these caches efficiently once the cachers have left the scene [1]. To protect their caches, corvids employ a suite of different cache-protection strategies that limit the observers’ visual or acoustic access to the cache site [2,3]....
Article
Full-text available
Many corvid species accurately remember the locations where they have seen others cache food, allowing them to pilfer these caches efficiently once the cachers have left the scene [1] . To protect their caches, corvids employ a suite of different cache-protection strategies that limit the observers’ visual or acoustic access to the cache site [2,3]...
Chapter
This third edition book with 19 chapters on domestic animal ethology is divided into two parts: Part A contains the basic elements of animal behaviour (chapter I, the study of animal behaviour and its application; chapter II, behaviour genetics, evolution and domestication; chapter III, behaviour and physiology; chapter IV, motivation and the organ...
Article
Full-text available
Positive and negative moods can be treated as prior expectations over future delivery of rewards and punishments. This provides an inferential foundation for the cognitive (judgement) bias task, now widely-used for assessing affective states in non-human animals. In the task, information about affect is extracted from the optimistic or pessimistic...
Data
Changes in mean (+/- SEM) (a) Affective Grid Activation score and (b) PANAS NA score across the study in Pleasant Room (solid line) and Unpleasant Room (dashed line) subjects. (EPS)
Article
Male Eurasian jays have been found to adjust the type of food they share with their female partner after seeing her eat 1 type of food to satiety. One interpretation of this behavior is that the male encoded the female’s decreased desire for the food she was sated on, and adjusted his behavior accordingly. However, in these studies, the male’s acti...