Georgia J Mason

University of Guelph | UOGuelph · Department of Animal and Poultry Science

Current frameworks for designing and evaluating good enclosures and "enrichments" typically focus on animals' active interactions with these features. This has undoubtedly improved the welfare of zoo-housed animals over the last 30 years or more. However, literature reviews from this same period identify persistent gaps in how such frameworks are a...

Animal welfare assessment relies on valid and practical indicators of affect. In mice, the most widely used research vertebrates, lying still with eyes open, inactive-but-awake (IBA) in the home cage, has potential to be one such indicator. IBA is elevated in barren, conventional housing compared with well-resourced, enriched housing, and predicts...

In carnivores, juvenile object play is hypothesized to improve the development of adult predation ability. We tested this hypothesis in a model carnivore, the American mink (Neovison vison). Play was induced via the provision of diverse “enrichment” objects to 32 litters from 4 to 15 weeks of age on a rotating schedule; control mink (32 litters) we...

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....

Background Over 120 million mice and rats are used annually in research, conventionally housed in shoebox-sized cages that restrict natural behaviours (e.g. nesting and burrowing). This can reduce physical fitness, impair thermoregulation and reduce welfare (e.g. inducing abnormal stereotypic behaviours). In humans, chronic stress has biological co...

Compared to peers raised in enriched environments (‘EE’), female laboratory mice from conventional barren cages are more aggressive to their cage-mates, and less sociable with familiar non-cage-mates (especially if these too are from conventional housing, ‘CH’). But how do such effects occur? Using Social Approach Tests, and middle-aged mice whose...

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...

Describing certain animal behaviours as ‘depression-like’ or ‘depressive’ has become common across several fields of research. These typically involve unusually low activity or unresponsiveness and/or reduced interest in pleasure (anhedonia). While the term ‘depression-like’ carefully avoids directly claiming that animals are depressed, this narrat...

Laboratory monkey ethograms currently include subcategories of abnormal behaviours that are based on superficial morphological similarity. Yet, such ethograms may be misclassifying behaviour, with potential welfare implications as different abnormal behaviours are likely to have distinct risk factors and treatments. We therefore investigated the co...

Consistent with boredom, prior work has found that mink raised in non-enriched (NE) or enriched (E) conditions differ in their motivations to seek stimulation: NE mink spent more time oriented towards and in contact with diverse stimuli presented to them (ranging from rewarding to aversive), and in one study, NE mink showed shorter latencies to con...

In humans, affective states can bias responses to ambiguous information: a phenomenon termed judgment bias (JB). Judgment biases have great potential for assessing affective states in animals, in both animal welfare and biomedical research. New animal JB tasks require construct validation, but for laboratory mice (Mus musculus), the most common res...

Resilience, the degree to which individuals are physiologically and behaviourally impacted by stressors, can be enhanced by positive experiences (e.g. positive moods in human, environmental enrichment in rodents). Such effects are important for human health, but could also have important animal welfare implications in terms of farm, laboratory and...

This study examined whether a history of beneficial social learning experiences affects social partner preferences in laboratory mice (Mus musculus) and whether observer mice acquire adaptive model-based social learning strategies through associative learning. We tested whether observers would come to socially prefer demonstrators who provide benef...

Responses to ambiguous and aversive stimuli (e.g. via tests of judgment bias and measures of startle amplitude) can indicate mammals’ affective states. We hypothesised that such findings generalize to birds, and that these two responses co-vary (since both involve stimulus evaluation). To validate startle reflexes (involuntary responses to sudden a...

This paper reviews a way of investigating health and welfare problems in captive wild animals (e.g., those in zoos, aviaries, aquaria, or aquaculture systems) that has great potential, but to date has been little used: systematically comparing species with few or no health and welfare issues to those more prone to problems. Doing so empirically pin...

Stereotypic behaviours (SBs) are common in confined animals including captive Carnivora, which display diverse forms of SB: often whole-body movements (e.g. pacing), but also head-only movements (e.g. head twirling) and ‘scrabbling’ (scratching at enclosure boundaries). Although often pooled together, emerging evidence indicates that SBs are hetero...

Voluntary wheel running occurs in mice of all strains, sexes, and ages. Mice find voluntary wheel running rewarding, and it leads to numerous health benefits. For this reason wheels are used both to enhance welfare and to create models of exercise. However, many designs of running wheel are used. This makes between-study comparisons difficult, as t...

Captivity often restricts animals' abilities to perform natural behaviour and explore novel stimuli. Here, we review how this constraint affects psychological welfare by preventing the meeting of motivations. One means by which this happens is through frustrating specific motivations pertaining to particular behavioural systems. This can occur when...

Measuring glucocorticoid metabolites in faeces has proven a useful, non-invasive method to monitor adrenocortical activity in several farm and wild species. Unlike plasma cortisol, whose sampling requires restraint and blood draws, faecal cortisol metabolites (FCM) may be particularly suitable for farmed silver foxes as these animals are sensitive...

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...

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...

Scientists and laypeople have long expressed concern that animals in non-enriched, unchanging environments might experience boredom. However, this had attracted little empirical study: the state is difficult to assess without verbal self-reports, and spontaneous behavioural signs of boredom can vary in humans, making it hard to identify signs likel...

Stereotypic behaviours (SBs) are sometimes assumed homogeneous, despite their diverse morphologies, as if sharing a common aetiology. However, if different SB forms are instead heterogeneous, they may have different causes, potentially impacting how best to prevent or manage them. We therefore conducted two exploratory studies with mink (Neovison v...

Regulations and guidelines assume that taller cages are better for mink, because they permit more diverse postures (e.g. standing upright) and freedom to move. New Canadian Codes of Practice therefore stipulate cage ceiling heights of at least 38 cm, while in Europe cages must be 46 cm or taller. However, minks’ food is placed on the cage top. To e...

The existence of play, a form of behaviour without obvious benefits to survival or reproduction, is a long-standing ethological mystery. Experiments in which socially deprived juvenile male mammals develop into sexually incompetent adults, along with widespread sexual dimorphism in rough-and-tumble play (R&T), suggest that R&T may prepare juvenile...

Mink are potentially ideal for investigating the functions of play: deleterious effects of early social isolation suggest a crucial developmental role for play; and huge numbers of highly playful juvenile subjects can be studied on farms. We collected descriptive data on 186 pairs from 93 litters, half provided with play-eliciting environmental enr...

In captive conditions (e.g. zoos), some Carnivora species typically show negligible stereotypic behaviour (SB) and reproduce successfully, while others tend to reproduce poorly and be very stereotypic. We used comparative methods to identify species level risk factors for SB and captive infant mortality (CIM). Candidate predictor variables were nat...

Enrichment studies for wild carnivores (e.g., in zoos) are often short-term, use enrichments of unknown motivational significance, and focus on glucocorticoids and stereotypic behaviour (SB), ignoring other stress-relevant variables. Our study assessed the broad behavioural and physiological effects of enriching American mink—a model carnivore—with...

Depressive-like forms of waking inactivity have been recently observed in laboratory primates and horses. We tested the hypotheses that being awake but motionless within the home-cage is a depression-like symptom in mice, and that in impoverished housing, it represents an alternative response to stereotypic behaviour. We raised C57BL/6 (‘C57′) and...

Background Inefficient experimental designs are common in animal-based biomedical research, wasting resources and potentially leading to unreplicable results. Here we illustrate the intrinsic statistical power of split-plot designs, wherein three or more sub-units (e.g. individual subjects) differing in a variable of interest (e.g. genotype) share...

Can simple enrichments enhance caged mink welfare? Pilot data from 756 sub-adults spanning three colour-types (strains) identified potentially practical enrichments, and suggested beneficial effects on temperament and fur-chewing. Our main experiment started with 2032 Black mink on three farms: from each of 508 families, one juvenile male-female pa...

This study investigated how the feeding behavior of pair-housed calves develops in response to reduced teat and feed place availability. Twenty Holstein bull calves were pair housed and provided with milk replacer (MR) and grain concentrate ad libitum via either (1) 1 teat and feed bucket/pen, such that calves could not feed simultaneously [competi...

Abstract Text: This study investigated the effect of competition during the milk-feeding stage on post-weaning feeding behavior and response to a competitive feeding challenge. Twenty Holstein bull calves were pair-housed and provided milk replacer (MR) and grain concentrate ad libitum via either: 1) 1 teat and feed bucket/pen (competitive feedin...

Abstract Text: This study investigated how pre-weaning housing environment affects intake and performance of dairy calves during the milk-feeding stage and once group-housed after weaning. Twenty Holstein bull calves were housed either individually (IH; n = 10) or paired and housed in pens (PH; n = 5) from birth until 49 d of age. Calves were off...

Captive parrots (Psittaciformes) commonly engage in “feather-damaging behaviour” (FDB) that suggests compromised welfare. Susceptibilities to FDB have been suggested, but not empirically demonstrated, to vary across the >200 species kept in captivity. Other demographic risk factors have been proposed for particular species – but neither confirmed n...

Wild carnivores in zoos, conservation breeding centres, and farms commonly live in relatively small, unstimulating enclosures. Under these captive conditions, in a range of species including giant pandas, black-footed ferrets, and European mink, male reproductive abilities are often poor. Such problems have long been hypothesized to be caused by th...

Standard practice typically requires the marking of laboratory mice so that they can be individually identified. However, many of the common methods compromise the welfare of the individuals being marked (as well as requiring time, effort, and/or resources on the part of researchers and technicians). Mixing strains of different colour within a cage...

The objectives of this study were to determine the effect of feed presentation on meal frequency and duration, as well as diurnal feeding patterns of dairy calves, and to assess any longer-term differences in feeding patterns resulting from previous experience. Twenty Holstein bull calves were exposed from wk 1 to 8 of life to 1 of 2 feed presentat...

Population dynamics predicts that on average parents should invest equally in male and female offspring; similarly, the physiology of mammalian sex determination is supposedly stochastic, producing equal numbers of sons and daughters. However, a high quality parent can maximize fitness by biasing their birth sex ratio (SR) to the sex with the great...

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This study investigated whether simple, cheap enrichments – ‘get-away bunks’ (a wire mesh semi-cylinder attached to the cage ceiling) and small manipulable objects (balls and suspended chewing items) – could improve welfare and productivity in nursing mink dams (Neovison vison) in commercial farm conditions in southern Ontario (Canada). Experiment...

This study examined how early exposure to different feed presentations affects development of feed sorting in dairy calves. Twenty Holstein bull calves were exposed for the first 8 wk of life to 1 of 2 feed presentation treatments: concentrate and chopped grass hay (<2.5 cm) offered ad libitum at a ratio of 7:3 as a mixture (MIX), or as separate co...

Farmed mink infants (Neovison vison) remain with their mothers beyond natural weaning age. This benefits their welfare, but can stress their mothers and contribute to illness (e.g. ‘nursing sickness’). European studies have explored augmenting cages with structures allowing mothers to get away from their infants (‘kits’); these show that if provide...

Highlights ► Billions of animals live in captive conditions very different from their ancestral environments. ► Some challenges resemble those for translocation and other forms of human-induced rapid environmental change (HIREC). ► Parallels between HIREC and captivity suggest that some species may struggle in both wild and captive environments. ►...

Effects of sub-optimal housing on inactivity vary across species and experiments, probably because inactivity is heterogeneous, reflecting both positive states (e.g. relaxation) and negative ones (e.g. fear). We therefore aimed to identify specific subtypes of inactivity that could indicate poor welfare in mink, by comparing their behaviour in enri...

Environmental enrichment (EE) reduces stereotypic behaviour (SB), but typically only partially. Using American mink (n = 17) as models, we tested the hypotheses that the effectiveness of EE reflects the degree to which subjects utilise it, and also the SB's degree of 'establishment' (its frequency and within-bout predictability). In Non-Enriched ca...

Animals housed in impoverished cages are often labelled 'bored'. They have also been called 'apathetic' or 'depressed', particularly when profoundly inactive. However, these terms are rarely operationally defined and validated. As a negative state caused by under-stimulation, boredom should increase interest in stimuli of all kinds. Apathy (lack of...

Studies spanning 15 species (including American mink, Neovison vison) demonstrate that within similarly-housed populations, individuals displaying high levels of stereotypic behaviour (SB) typically show perseverative responding (e.g. during set-shifting, or reversal/extinction learning). Similar correlations in autism and schizophrenia suggest thi...

Mortality rates are often used in population-level animal welfare assessments because they are assumed to reflect rates of disease or injury and other problems likely to cause poor welfare. High mortality is thus assumed to correlate with factors likely to cause negative affective states. Here, we argue that negative affective states are also relat...

Stereotypic behaviors are repetitive invariant behaviors that are common in many captive species and potentially indicate compromised welfare and suitability as research subjects. Adult laboratory mice commonly perform stereotypic bar-gnawing, route-tracing, and back-flipping, although great individual variation in frequency occurs. Early life fact...

Stable individual differences in activity levels within populations have been linked to differences in reproductive rate or parental care in several species, including American mink (Neovison vison). Fur‐farmed mink are good models for studying such effects because they yield large sample sizes and readily allow investigations into maternal behavio...

Meagher, R., Bechard, A., Palme, R., Diez-Leon, M., Hunter, D. B. and Mason, G. 2012. Decreased litter size in inactive female mink (Neovison vison): Mediating variables and implications for overall productivity. Can J. Anim. Sci. 92: 131-141. Farmed mink vary dramatically in activity: very inactive individuals rarely leave the nest-box, while othe...

Physical disability has the potential to impede the use of environmental enrichments in rehabilitation programmes. We therefore compared the behaviour of 63 disabled and non-disabled socially housed adult Asiatic black bears rescued from bile farms for 103 observation hours. Amputees were less active than non-amputees, spent less time standing, tra...

Environmental enrichment typically improves learning, increases cortical thickness and hippocampal neurogenesis, reduces anxiety, and reduces stereotypic behaviour, yet sometimes such effects are absent or even reversed. We investigated whether neophobia governs how mice interact with enrichments, since this could explain why enrichments vary in im...

Subjects were 2,400 kits from 600 families, on 3 commercial farms in Ontario, pair-housed from July-December. 75% were Blacks, 25% Demis. Two male-female pairs were used per family: one was provided with stimuli for interaction; the other housed in standard conditions. The supplemented cages received a golf ball, plastic wiffle ball, and hanging de...

The flexible social organisation in red foxes (Vulpes vulpes) suggests that social contact could enrich the housing of silver fox vixens (a selected line of red foxes) farmed for their fur. To investigate their social motivation, adult vixens housed in an operant apparatus were allowed to pull a loop for full physical contact with a same-aged vixen...

Understanding how birth origin (whether born in the wild or captivity) influences behavioural development is important for fundamental and applied ethology, especially when captive-bred (CB) individuals from wild species are used in research or conservation. CB animals are typically much more prone to stereotypic behaviour (SB) than are wild caught...

Fear in farm animals is a welfare and economic concern. For Scandinavian mink, the “stick test” is common for assessing fearfulness: a spatula is inserted into the cage and minks’ immediate responses are noted. However, on Ontario farms, fearfulness in the stick test was very rare and aggressive responses were prevalent, rendering this test poor fo...

The behaviour and physiology of wild animals born in zoos, laboratories and breeding centres can differ substantially from that of their wild-caught (WC) conspecifics. For instance, captive-born (CB) animals are typically more prone to developing abnormal repetitive behaviours. In captive striped mice, Rhabdomys, we first confirmed that birth origi...

Environmental enrichment typically improves learning, increases cortical thickness and hippocampal neurogenesis, reduces anxiety, and reduces stereotypic behaviour, yet sometimes such effects are absent or even reversed. We investigated whether neophobia governs how mice interact with enrichments, since this could explain why enrichments vary in im...

D. A. Conde and colleagues' Policy Forum “An emerging role of zoos to conserve biodiversity” (18 March, p. [1390][1]) presents an inspiring view of zoos' potential contributions to conservation through captive breeding and reintroduction. However, their analysis overlooks two key issues. First

Adding environmental enrichments to a previously resource-poor cage or enclosure can sometimes cause elevated aggression in socially housed animals, due to competition over the provided resources. Here, using female C57BL/6J mice, we investigated whether the way that environmental enrichments are distributed affects the risk of negative interaction...

We analysed the relationship between abnormal repetitive behaviour (ARB), the presence/absence of environmental enrichment, and two types of behavioural disinhibition in farmed American mink, Neovison vison. The first type, recurrent perseveration, the inappropriate repetition of already completed responses, was assessed using three indices of exce...

Barbering (incessant grooming) is an abnormal behavior causing alopecia and commonly affects various strains of laboratory mice, including C57BL/6J. Barbering-induced alopecia is a potential symptom of brain impairment and can indicate a stressful environment. We compared alopecia prevalence and severity in mice housed in enriched or standard cages...

Captivity often restricts the abilities of animals to perform natural behaviour. Here, we review how this constraint affects psychological welfare by preventing motivations from being satisfied. One means by which this happens is through frustrating specific motivations pertaining to particular behavioural systems. This can occur when constrained b...

This second edition book is a collection of topics on animal welfare from 46 authors of varying expertise of 15 countries. The book is composed of five parts: I (issues), introduces the background and philosophy of animal welfare; II (problems), covers problems of animal welfare; III (assessment), considers various approaches to the assessment of a...

Severe feather pecking, a potentially stereotypic behaviour in chickens (Gallus gallus), can be reduced by providing enrichment. However, there is little comparative information available on the effectiveness of different types of enrichment. Providing forages to birds is likely to decrease feather-pecking behaviour the most, as it is generally tho...

Approximately 26 billion animals, spanning over 10 000 species, are kept on farms and in zoos, conservation breeding centers, research laboratories and households. Captive animals are often healthier, longer-lived and more fecund than free-living conspecifics, but for some species the opposite is true. Captivity is a very long way from the ideal 'c...

For captive animals, living in barren conditions leads to stereotypic behaviour that is hard to alleviate using environmental enrichment. This resistance to enrichment is often explained via mechanisms that decouple abnormal behaviour from current welfare, such as ‘establishment’: a hypothetical process whereby repetition increases behaviour’s pred...

The objective of this study was to determine how different feeding methods may affect the learning of feeding, sorting, and competitive behavior of growing dairy heifers. We hypothesized that heifers previously fed a total mixed ration (TMR) would distribute their feeding time more evenly throughout the day, sort the new ration less, compete less f...

Juvenile wild house mice leave their mothers at 8 weeks (+). In contrast, laboratory strains of mice (lab mice) are typically ‘weaned’ at postnatal day (PND) 21. Lab mice might mature faster than their wild forebears; but if they do not, standard laboratory weaning likely involves maternal deprivation. We therefore investigated when lab mice volunt...

The objective of this study was to determine the effects of feed delivery method on growth, feeding competition, feeding, and sorting behavior of dairy heifers. Thirty-two Holstein heifers (146.2+/-21.9 d of age) were divided into 8 groups of 4 and exposed to 1 of 2 feed delivery treatments for 13 wk. The treatment rations contained 65% grass/alfal...

Animal welfare (sometimes termed "well-being") is about feelings - states such as "suffering" or "contentment" that we can infer but cannot measure directly. Welfare indices have been developed from two main sources: studies of suffering humans, and of research animals deliberately subjected to challenges known to affect emotional state. We briefly...

To assess zoo elephants' welfare using objective population-level indices, we sought data from zoos and other protected populations (potential "benchmarks") on variables affected by poor well-being. Such data were available on fecundity, potential fertility, stillbirths, infant mortality, adult survivorship, and stereotypic behavior. Most of these...

Stereotypic behaviours are common in animals in impoverished housing, arising from two complementary processes: (1) thwarted attempts to perform motivated behaviours; (2) forebrain dysfunction impeding normal behavioural inhibition. When enriched animals are moved to impoverished housing, they are sometimes protected against developing stereotypic...