Reimagining Armadillo Husbandry: Applying an Enrichment Framework to Support Ex Situ Conservation

Abstract

Environmental enrichment (EE) is a vital component of modern zoo husbandry, improving welfare by encouraging natural behaviours and supporting ex situ conservation goals. While EE is widely integrated into the management of many taxa, its welfare benefits remain poorly understood for certain species. The armadillos are examples of such species—underrepresented in research with few targeted EE strategies. Importantly, although olfaction is recognised as their primary sensory modality, methods to promote behaviour linked to olfaction (e.g., exploration and foraging) remain unclear. This review synthesises knowledge on EE for armadillos, using Bloomsmith’s five categories of enrichment and Positive Reinforcement Training (PRT) as a framework. We identify species-typical behaviours to maintain in captivity, consider their ecological relevance in the wild, and explore how tailored EE and PRT can adjust environments. We then evaluate how such approaches can enhance behavioural outcomes, support visitor engagement, and promote welfare critical for in situ and ex situ conservation. Furthermore, we highlight EE’s role in safeguarding adaptive traits for population sustainability and argue that integrating EE and PRT into a broader One Plan Approach provides a pathway for aligning ex situ management with wild ecology. Finally, we identify key gaps, emphasising multi-institutional collaboration, standardised metrics, and long-term research to guide evidence-based practices for armadillos.

1. Introduction

Zoo populations of conservation concern, while rarely reintroduced, remain essential for safeguarding genetic viability and long-term sustainability [1,2]. Therefore, husbandry decisions and management practice require the integration of care plans and strategies that support behaviour and welfare, ensuring that zoo animals retain traits similar to wild counterparts that are necessary for survival [3]. For example, enabling animals to perform adaptive behavioural traits at frequencies and durations comparable to those observed in wild conspecifics may help maintain behaviours necessary for survival in the wild across generations [4] and promote welfare states whilst accommodated in the captive environment [5]. The IUCN Species Survival Commission (SSC) Conservation Planning Specialist Group (CPSG)’s “One Plan Approach to Conservation” (OPA), in which ex situ and in situ populations are integrated into standardised conservation plans for a species [6], can help achieve this. By incorporating the behavioural needs and ecology of wild populations into captive management, and in turn using zoo-based insights to inform in situ action, the OPA ensures that conservation planning is evidence-based and cohesive across all populations. Similarly, ex situ populations can support advocacy, engagement, and capacity building efforts, and be insurance populations where key adaptive traits are conserved for the future.

As an example of this integrated approach, carefully designed environmental enrichment (EE) programmes play a crucial role in promoting adaptive behavioural traits, such as those linked to foraging and reproduction [7]. However, there remains a scarcity of evidence regarding which EE regimes are most effective in encouraging these targeted behaviours [8]. Evidence-based approaches, underpinned by biological evidence, such as published enrichment research and data on species-specific ecology, physiology, and behaviour, are essential to meeting welfare needs [9]. Given the vast diversity of species housed in zoos, many remain poorly studied, including the armadillos (Cingulata), which comprise 21 extant species. Concerningly, the most recent International Union on the Conservation of Nature (IUCN) Red List assessments show that four of these species are categorised as “Vulnerable” with a further four species classified as “Data Deficient” [10]. This highlights the need to develop targeted husbandry strategies, including EE approaches for armadillos to ensure their viability in captivity.

Armadillos belong to the order Xenarthra, a group of mammals that also includes anteaters and sloths [11]. They are split into two families: Dasypodidae and Chlamyphoridae [12]. Armadillos are considered mostly nocturnal and crepuscular [13], however temperature effects on activity patterns differ amongst species [14]. Species within the family Dasypodidae exhibit jaw morphologies adapted for specialised, insectivorous diets, whereas species in the Chlamyphoridae family show more generalist feeding strategies [15].

Armadillos are rarely seen in the wild [16,17], spending much of their time underground [18]. However, they are popular amongst visitors to zoos and can be prominently featured in zoo exhibits. For example, southern three-banded armadillos (Tolypeutes matacus) have featured in the “Rainforest Life” exhibit at London Zoo [19], benefiting from the space and complexity that the substrate of an indoor rainforest exhibit can provide. However, even in zoos, their inclination to be underground should be factored into exhibit design and enclosures need to enable burrowing whilst being escape-proof and enable staff to monitor their whereabouts. Although these species are found in zoos globally [20], behavioural research on armadillos, both in and ex situ, remains scarce. Other Xenarthran species, such as anteaters (Myrmecophagidae), have also received little attention in the literature and this may be due to the cryptic nature of Xenarthrans, which makes them difficult to study in wild environments [21]. Moreover, only a small proportion of mammalogists focus their research on this taxonomic group [22], resulting in significant gaps in understanding of their behavioural ecology. Consequently, behavioural and ecological research should focus more on these species to improve understanding of how EE can promote behaviours indicative of positive welfare.

EE may now seem commonplace thanks to the efforts of behavioural experts such as Hal Markowitz, who is widely regarded as a pioneer in the field of enrichment for zoo-housed species [23,24]. During the 1970s, Markowitz’s research focused on the design and implementation of enrichment devices to facilitate a deeper understanding of animal learning processes [25]. The concept of providing EE for zoo animals continued to gain traction in the literature [26,27,28], where it was emphasised that captive environments should prioritise behavioural needs and animal welfare [29]. Later, Shepherdson [30] highlighted that contemporary study of EE represents a more systematic and scientific approach, drawing on ethology, psychology, and animal science to address the psychological and behavioural needs of captive animals.

Bloomsmith et al. [31] proposed a comprehensive framework for EE, originally conceived to improve the wellbeing of non-human primates in captive facilities within five broad categories: social enrichment (including both contact and non-contact forms); occupational enrichment (encompassing psychological challenges or exercise-based activities); physical enrichment (involving modifications to the enclosure and the provision of enrichment devices); sensory enrichment (such as visual, auditory, or other sensory stimuli); and nutritional enrichment (focusing on the type, delivery, and presentation of food). This framework has since been adopted widely to address the behavioural and psychological needs across the diverse range of species housed in zoos [32], leading to animals benefitting from positive life experiences as a result.

The five categories of EE enable caretakers to devise enrichment programmes tailored to the needs of the species and the environments in which they are housed. Although originally devised for non-human primates, the framework is adaptable across taxa. For example, EE involving playback of conspecific breeding call auditory signals promoted reproductive behaviours and breeding success in captive Northern bald ibis (Geronticus eremita) [33]. However, EE programmes must be developed carefully to promote success in their implementation. For example, research by Asencio et al. [34] found that in captive lesser anteaters (Tamandua tetradactyla), close relatives of armadillos, EE centred on food-related items was not effective in increasing positive activity.

EE types do not need to be provided in isolation, nor are these five categories mutually exclusive; rather, combining multiple categories may be particularly beneficial. For example, preliminary research into the effectiveness of EE for zoo-housed armadillos suggests that a combination of nutritional and multi-sensory EE may be more successful in encouraging natural foraging and exploratory behaviours than those reliant on a single EE type [35]. However, research into the effectiveness of EE is still biased towards charismatic mammals, predominantly primates [36]. Thus, further research is warranted into how EE affects behavioural outputs in armadillos. In addition to integrating EE across categories, its conceptualisation should be guided by the species’ specific behavioural needs (e.g., foraging or reproductive behaviours) to ensure that they are functional, rather than being based on aesthetic or novelty value prioritised from an anthropocentric perspective [37].

A sixth component has emerged as an additional category of EE: the integration of Positive Reinforcement Training (PRT). The idea that PRT could be considered a form of EE was initially proposed by Melfi [38] who argued that PRT is enriching if it provides the animal with an opportunity to learn. Westlund [39] also states that comprehensive training programmes that encourage species-specific behaviours and offer behavioural choice to the animal can be considered enriching. Spiezio et al. [40] found that implementing PRT for zoo ring-tailed lemurs (Lemur catta) caused a significant increase in affiliative behaviours, whilst decreasing the occurrences of aggressive behaviours, thereby enhancing animal welfare. However, future research should continue exploring PRT to deepen our understanding of its effects as a broader EE framework across species in zoos.

The usefulness of the Bloomsmith EE model, the ease of execution of the five categories, as well as the overlap between categories (which means one form of enrichment can promote multiple behavioural opportunities) mean that we have chosen it as a focus of this article. The main aim of this review is to conceptually explore how Bloomsmith’s model of five EE categories, along with PRT, can be applied to armadillos in captive environments. Together, these approaches can help to support conservation-aligned outcomes related to the behavioural needs of the species. Ultimately, this article seeks to demonstrate how integrated EE- and PRT-centred approaches can contribute to a holistic, welfare-focused framework for managing armadillos in captivity.

2. A Review of Armadillos in Zoos

Armadillos under human care are relatively widespread. According to the Zoo Information Management System (ZIMS) database, there are 819 individuals kept in 354 zoos globally (as of July 2025) [19]. However, across the 21 extant species, not all are equally well represented, with southern three-banded and six-banded (or yellow) (Euphractus sexcinctus) armadillos amongst the most commonly seen in zoos [19].

2.1. An Overview of Armadillos Commonly Kept Under Human Care

As well as being commonly seen in the zoo, of particular scientific interest in a laboratory environment is the nine-banded armadillo, for both its polyembryonic reproductive strategy (females give birth to quadruplets that are genetically identical [41]) and for being the only non-human species that can naturally acquire leprosy [42]. Consequently, this species is frequently used in laboratory research, and advances in EE, along with associated improvements in welfare, have the potential to benefit multiple individuals across different facilities.

As of July 2025, ZIMS data [19] indicate that there are 61 nine-banded armadillos (Dasypus novemcinctus) in zoos worldwide. Across the two three-banded armadillo species, the Brazilian three-banded armadillo (Tolypeutes tricinctus), and the southern three-banded armadillo, there are a total of 456 individuals. In addition, 113 large hairy armadillos (Chaetophractus villosus) and 139 six-banded armadillos are held in zoos internationally.

Limited understanding of species’ biology and ecology causes challenges for captive care [43]. Integrating aspects of a species’ natural history can help create benchmarks to improve the welfare of animals by ensuring their needs in terms of behaviour, social dynamics, and dietary provisions are met [44,45]. Also, studying the behavioural ecology of animals in the wild can help to define which natural behaviours are desirable, and should therefore be promoted in the zoo [46]. The combination of semi-fossorial behaviour, characterised by periods spent underground in simple, self-constructed burrows for shelter or nesting [47], and primarily nocturnal activity renders armadillos particularly difficult to observe in the wild, making it challenging to benchmark behavioural repertoires that are suggestive of positive welfare in the zoo.

If husbandry practices and environmental conditions are insufficient, armadillos may suffer from a range of health complications due to such deficiencies. Diniz et al. [48] reported a high incidence of injuries and respiratory disorders among captive individuals, attributing these to inadequate flooring and substrate choices. Such conditions may also increase susceptibility to bacterial infections. These findings emphasise the importance of evidence-based husbandry and enclosure design for safeguarding the physical health and welfare of captive armadillos.

The responses of armadillos to some sensory stimuli are not clearly understood, further highlighting challenges in their care. For example, they may be sensitive to auditory stimuli [49], which in the zoo sound environment could induce stress, as documented in other sound-sensitive species such as giraffes (Giraffa sp.) [50] and chimpanzees (Pan troglodytes) [51]. Research by Baird et al. [52] found that handling in zoos increased faecal glucocorticoid (GC) concentrations—a physiological indicator of stress [53,54]. Thus, other unfamiliar stimuli may also have effects, but further research is needed to determine which aspects of captivity most influence armadillo welfare.

One of the most scarcely kept armadillo species is the pink fairy armadillo (Chlamyphorus truncatus). Due to the species’ elusive nature and the scarcity of data from the wild, zoos have limited reference points for guiding effective husbandry practices in captivity. One case study in the literature suggested that environments with ample hiding spaces and an abundance of compacted sand could help to maintain them in captivity [55]. However, it should be noted that even minor environmental modifications appeared to elicit a stress response. The individual survived for only eight months in captivity, with the authors suggesting that death may have resulted from an inadequate diet due to our limited understanding of the species’ nutritional requirements. Despite being classified as “Data Deficient” [10], this species is likely of conservation concern due to multiple factors, including agricultural expansion, predation by feral animals, and lack of local protections on the species [56]. This highlights the need to improve understanding of species’ behavioural ecology, to ensure that if captive populations are necessary due to continued wild declines, behavioural needs are met, and positive welfare outcomes can be achieved.

Some aspects of the captive environment may lead to an increase in stereotypic behaviours in captive armadillos. Baird et al. [52] found that human interactions caused an increase in pacing behaviour in southern three-banded armadillos and screaming armadillos (Chaetophractus vellerosus). Kelly and Rose [35] found that there was no relationship between increased stereotypies and visitor numbers. Similarly, Cortés Duarte et al. [57] found that armadillos performed no abnormal behaviours, but note that they were inactive for most of the observation period. Outside of these documented case studies, empirical evidence which investigates behavioural measures of welfare in captive armadillos remains scarce. This necessitates further research that explores how aspects of the human-managed environment may affect behavioural outputs, and, subsequently, welfare in captive armadillos.

To maintain viable insurance populations in captivity and develop management guidelines that support reproductive success, it is vital to understand the reproductive biology of species and which restrictions in the captive environment may impede breeding. Early research in captive nine-banded armadillos indicated that reproductive failure was high due to physiological changes (i.e., increased circulating progesterone) caused by undetermined stressors [58]. Implementation of EE can promote reproductive success by encouraging species-specific reproductive behaviours [59] and mitigating the negative physiological effects associated with stress [60]. Cortés Duarte et al. [57] found that reproductive events were observed when armadillos were presented with EE. As it is integral to conservation success for more at-risk species (such as the southern three-banded armadillo) to promote reproduction so that insurance populations remain viable in terms of population stability and display of adaptive behavioural traits, EE should be explained in husbandry guidelines and provided in daily care.

Compared to more charismatic mammal species, armadillos remain comparatively understudied in zoos [49], and published guidelines on husbandry protocols are scarce. Much research on captive armadillos concludes that overall activity remains low [57], and indicators of stress, including stereotypical behaviours and increased faecal GC concentrations, are observed [52]. This likely reflects husbandry and management practices that do not capture the complexity of armadillos’ natural behavioural ecology, with limitations in replicating key environmental variables, such as diet, lighting, and temperature, and a lack of understanding of their multisensory modalities. This highlights the need to continue research into the behavioural ecology of these species to best promote welfare outcomes in the captive environment.

2.2. Opportunities to Advance Armadillo Care

Mounting research highlights the importance of species-specific evidence-based husbandry for promoting positive welfare [61], as behavioural and ecological differences across taxa require tailored approaches in captivity. Despite their distinctive morphology and behaviour, armadillos remain understudied compared with more commonly housed and charismatic species, such as primates and large carnivores. With their evolutionary distinctiveness, armadillos offer a unique opportunity to serve as charismatic ambassador species in zoo-based education, while also holding potential for future reintroduction or release into the wild as part of ex situ conservation efforts.

This presents a valuable opportunity to focus study efforts on armadillos in both wild and captive settings to better understand their species-specific needs. Such knowledge is essential for developing practical, evidence-based husbandry guidelines that can be incorporated into zoo management practices, helping to meet regulatory frameworks, including the Standards of Modern Zoo Practice for Great Britain [62], and other institutional protocols. Given the current paucity of armadillo-specific guidance, developing and disseminating these guidelines globally could play a critical role in enhancing welfare for these species under human care.

Due to their semi-fossorial tendencies and the large proportion of time they spend foraging and rooting [14,63,64], substrate provision is a fundamental component of armadillo husbandry. Providing appropriate substrates not only promotes natural behaviours but also reflects key aspects of their ecological role in the wild. Armadillos contribute significantly to ecosystem health in South America. A comprehensive assessment by Vale et al. [65] highlighted their provision of vital ecosystem services, including pest and disease control, seed dispersal, and ecosystem engineering. Through bioturbation, armadillos enhance soil health by promoting nutrient cycling, microbial diversity, and carbon storage [66]. These roles position armadillos as an important component of sustainable ecosystems. In the zoo, these ecological characteristics can be effectively integrated into education programmes. Encouraging natural foraging and rooting behaviours provides opportunities to engage and educate visitors on the ecological services armadillos perform, thereby enhancing their educational and ambassadorial value [64,67,68]. This aligns with the core aims of the modern zoo to promote the importance of sustainability and biodiversity conservation.

To further enhance the public awareness of global biodiversity conservation and sustainability issues in zoos, species can take on ambassador roles. Ambassador animals serve to educate visitors about conservation issues through daily presentations and interactive sessions, or through outreach programmes [69]. Research shows that human–animal interactions (HAI) associated with ambassador animals promote pro-environmental behaviours and visitor perceptions of captive animal welfare [70,71]. Although scarcely investigated in armadillos, preliminary findings indicate that they can be effective ambassador animals in zoos, but their nocturnal habits may pose challenges [72]. Future research should continue to investigate the effectiveness of armadillos as ambassador species in the zoo environment.

3. Applying Bloomsmith’s Five Enrichment Categories to Armadillos

A holistic approach to EE for armadillos should utilise a range of the categories outlined by Bloomsmith, Brent, and Schapiro [28], where possible, to better understand species’ responses, particularly as there is currently a paucity of research indicating which types of EE are most effective at promoting behavioural outputs. The categories of EE are not mutually exclusive; accordingly, a single EE provision may elicit multiple behavioural benefits, thereby enhancing the overall positive experience of the individual animal. Below are some examples of how EE could be moulded around each of the five categories, based on our current understanding of armadillo biology and ecology. Figure 1 summarises how each of these categories could be implemented for armadillos in a zoo context.

3.1. Social Enrichment

Armadillos may be found in male–female pairs in the wild, or occasionally in sibling groups when food is abundant [73], despite normally being solitary [14,74]. Opportunities for pair or social foraging may support the expression of adaptive behaviours. For example, McDonough and Loughry [75] reported that vigilance behaviours in male nine-banded armadillos increased when in close proximity to foraging females, thereby promoting threat-avoidance strategies. Social foraging may also facilitate mate choice. In six-banded armadillos, male chasing behaviour has been documented in the wild, likely associated with competition for access to females [76]. However, further wild behavioural data are required to determine how mate selection occurs across all species.

In zoos, armadillos are often housed individually or in pairs [35]. Such opportunities could be provided through food-based EE, including multiple puzzle feeders or scatter feeding in shared spaces for limited periods, after which individuals may be returned to individual or pair housing.

3.2. Occupational Enrichment

Armadillos spend much of their active time foraging in the wild, with up to 90% of activity devoted to this behaviour [63]. Therefore, encouraging foraging, exploration, and problem-solving should be prioritised for individuals in captivity. EE that requires manipulation or problem-solving (e.g., puzzle feeders, or plastic balls used in the case study by Kelly and Rose [35]) may encourage activity and natural foraging. However, the extent to which smell encourages these behaviours, or whether different scents are most effective at encouraging activity, has not yet been explored, warranting further investigation. Promoting foraging behaviour in captivity could be supported by replicating olfactory cues that armadillos respond to in the wild. Data from wild populations could therefore be analysed to identify which scents are most effective, and these could then be incorporated into EE provision. Additionally, naturalistic objects, such as logs containing dietary items (e.g., mealworms or other invertebrate prey) may also promote natural foraging and encourage the use of their dextrous and long tongues [77] to extract food as they would in the wild.

More sophisticated forms of EE may be trialled to encourage problem-solving. In a multidisciplinary workshop conducted by French et al. [49], in collaboration with zoo professionals and technologists, the construction of an underground tunnel system was proposed. This system would use motion-sensor LEDs to indicate the armadillo’s location above ground, promoting natural foraging behaviours. Not only could this be provided to encourage armadillos to explore their environment with opportunities for problem-solving and food extraction similar to in the wild, but it could also promote interaction with zoo visitors. Utilising such technology to create EE may create a more engaging and interactive experience for zoo visitors.

3.3. Physical Enrichment

Facilitating exploratory, locomotory, and digging behaviours may enhance armadillo welfare, as these activities reflect species-typical patterns observed in wild conspecifics [63]. Movable hides, rather than those fixed in place, may encourage animals to use different enclosure areas and promote these behaviours. Anecdotal observations by the author suggest that armadillos in captivity often dig substrate into their hides before resting, a behaviour that may reflect natural nest-building tendencies [78].

Armadillos possess forelimb morphology well-adapted for digging [79], but substrate type may influence burrow depth. For example, burrows constructed by three-banded armadillos (Tolypeutes sp.) are often shallow, possibly reflecting the hard soil types encountered in their natural range compared with other species [80]. Moreover, because armadillos occupy diverse geographic ranges, both habitat type and substrate use vary across species [15]. Accordingly, ecological data on substrate composition and use in the wild should be collected across armadillo species to determine which soil types are most frequently selected for digging and burrow construction, and these preferences can then inform the provision of suitable substrates in captivity.

In the zoo, EE trials could involve distributing hides throughout the enclosure, each surrounded by different substrate types (e.g., sand, soil, bark chip), to assess where armadillos spend the most time and which conditions elicit greater exploratory or rooting behaviour. Such trials could be paired with space-use studies to determine whether animals show preferences for particular enclosure zones depending on the substrates provided [81].

3.4. Sensory Enrichment

Sensory enrichment, particularly olfactory-based EE can support species-typical behaviours, such as foraging and exploration, while reducing abnormal repetitive behaviours (ARBs) that may indicate frustration, thereby promoting animal welfare [35,82].

Research by Clark and Melfi [83] also found that EE scented with natural spice promoted digging and rooting behaviour in nine-banded armadillos, but that interest in the device waned over time as the scent dispersed. Utilising OPA, partly informed by in situ research, may further guide the conservation of natural olfactory responses in captive populations through the provision of scent-based enrichment that is ecologically relevant as the design of such EE is based on wild data.

Armadillos can distinguish between different odours [84], but more data are needed on the scent cues used in the wild for foraging, nesting, and social behaviours to identify ecologically relevant stimuli that can inform olfactory EE in zoo-housed individuals. In captivity, scent trails could be trialled to promote the use of enclosure space or to direct animals towards puzzle feeder EE devices, particularly given their poor eyesight [85], which may otherwise hinder detection. Additionally, scent trails may help to disrupt pacing behaviour, an ARB associated with poor welfare, which has been observed in captive armadillos [52].

To strengthen the evidence base for such approaches, ecological studies are required on the sensory biology of armadillos, including which scent cues are naturally used during foraging, mate location, or territory marking, and how these vary among species and habitats. Further research should also investigate which sensory modalities beyond olfaction, such as sight, hearing, and taste, elicit behavioural responses in wild armadillos. For example, they may respond to auditory cues when detecting prey [86], but these abilities remain poorly understood. Such insights would ensure that enrichment in captivity reflects ecologically relevant stimuli, thereby maximising welfare benefits across armadillo species.

3.5. Nutritional Enrichment

Foraging activity, such as digging and rooting, is a key behavioural goal for captive armadillos, as this reflects natural activity patterns observed in the wild. Provision of food-based EE may help facilitate such behaviour [83]. Although armadillos possess strong olfactory senses [87], Kelly and Rose [35] found that scatter-feeding provision did not reliably increase foraging activity, suggesting that olfactory stimulation alone may not be sufficient. One possible explanation is the substrate type, as coarse bark chip may limit foraging success, particularly when live invertebrate items are scattered randomly and can quickly bury out of reach.

Clark and Melfi [83] show that providing soil dig pits encourages digging and rooting behaviour in armadillos, as well as increased time spent in the enriched exhibit area. Therefore, designated digging areas with substrates requiring longer periods to excavate, such as soil or sand, may enhance scatter-feeding EE compared with bark chip. Different substrate types could be trialled to assess which most effectively extend foraging duration through the use of dig pits.

Food preference may also influence motivation to forage. If prey items offered are not favoured, individuals may not invest effort, and when rewards for contrafreeloading (working for food rather than consuming freely available food [88]) are low, items may be ignored. Contrafreeloading is effective in species where wild foraging builds anticipation for a reward, such as in domestic pigs (Sus scrofa) [89]. Thus, in armadillos, rotating invertebrate types in scatter-feeding EE trials may therefore help identify which options best promote contrafreeloading, as naturalistic tasks, such as rooting for prey, may evoke anticipation and subsequent reward, which will be absent in bowl feeding.

Although many armadillo species are recognised as opportunistic foragers [74,90], some are more specialist; for example, the six-banded armadillo predominantly consumes Hymenoptera [91]. Thus, to optimise this EE approach, wild data are needed on the natural foraging ecology of armadillos, including which prey types are most frequently targeted, how prey is located (e.g., by scent or substrate disturbance), and the substrates typically encountered during foraging. Integrating this information would help design enrichment that mirrors ecologically relevant foraging challenges and supports species-typical behavioural expression in captivity.

4. Is Training the Key to Enhanced Armadillo Enrichment?

Training has become an increasingly important aspect of modern zoo management, serving both practical and welfare-focused roles, including improving human–animal bonds [92]. By enabling animals to participate voluntarily in husbandry routines or events (e.g., health checks), training reduces the need for invasive procedures and can alleviate stress associated with handling and restraint [93]. It also provides cognitive stimulation, thereby promoting welfare through positive challenge [94,95]. For species such as armadillos, where little is known about their cognitive abilities, training may also be beneficial in encouraging the performance of natural behaviours, such as foraging, digging, and exploration.

4.1. Positive Reinforcement Training in Captive Animal Management

Positive Reinforcement Training (PRT) involves adding a valued stimulus to increase a desired behaviour [96]. In animal training, positive reinforcers may include preferred food, enrichment, tactile interaction, companionship, or caregiver attention [87]. It has become established as a tool, integrated within husbandry practices to promote welfare outcomes for zoo animals. Its application has been suggested as a management strategy for abnormal behaviours. Undesirable behaviours can be reduced by training incompatible or maladaptive behaviours, addressing underlying causes such as fear through desensitisation, or by encouraging alternative, natural behavioural responses [88]. PRT is multipurpose, commonly used in routine husbandry tasks, such as health checks, which might otherwise be stressful and invasive (e.g., for carnivores). It also benefits keepers by saving time and reducing costs associated with such procedures. Additionally, the implementation of PRT in zoo-housed chimpanzees not only facilitated the presentation of body parts for health checks but also acted as a form of EE by encouraging the performance of behaviours indicative of positive welfare (i.e., prosocial affiliative behaviours) and significantly reducing abnormal behaviours [89]. However, similar to EE, research into the application of PRT as a species husbandry and management tool is disproportionately skewed towards charismatic species, including primates, with a focus on studies investigating cognitive bias, the process by which emotional states affect cognition [90]. There is limited empirical evidence on the success of PRT application in Xenarthrans. Anecdotal evidence in giant anteaters (Myrmecophaga tridactyla) indicates that target training can work successfully to move individuals around the zoo without requiring physical restraint [91] which may reduce stress in some animals [92]. Additionally, Amendolagine et al. [93] found that PRT using food items as a reinforcer was successful in both urine sample collection procedures and weight training. However, as the effectiveness of PRT (both as a form of engagement with care and as enrichment) for armadillos warrants further investigation.

4.2. Applications of PRT for Armadillos

The extent to which armadillos possess cognitive abilities suitable for PRT in the zoo is not well understood, and application of PRT has been scarcely explored in armadillos. To the authors’ knowledge, there are currently no published studies analysing the success of PRT in zoo armadillos. However, preliminary research by Vincent and Vonk [84] demonstrated the ability of armadillos to distinguish between different scents in a novel learning task. Additionally, Papini et al. [97] demonstrated that giant armadillos possess similar cognitive capabilities in spatial tasks to those of American opossums (Didelphis virginiana). Due to the more well documented cognitive abilities of opossums [98,99,100], it is therefore plausible that armadillos may perform well in other spatial tasks. Thus, PRT could incorporate scent-based cues for husbandry tasks, such as crate training for weighing and transportation, and health checks and target training to encourage locomotion and utilisation of enclosure space. Desensitising armadillos to routine husbandry tasks may also have positive welfare impacts. Research by Baird et al. [52] found that exposure to handling increased faecal GC concentrations, a physiological indicator of stress [53,54]. Therefore, mitigating the need to handle armadillos in procedures including crate training and health checks by using PRT may lower the stress associated with them. Further, the effect of PRT as a form of EE has been investigated in animals housed individually, demonstrating in rhesus macaques (Macaca mulatta) that it can be effective at ameliorating high frequencies of abnormal behaviours in animals at risk [101]. This may be applicable to armadillos, which are often housed solitarily or in breeding pairs.

4.3. Utilising PRT to Complement Bloomsmith’s EE Framework

When integrated, PRT fits within EE programmes as a way of complementing Bloomsmith’s five categories, particularly occupational and sensory EE, by aligning with armadillos’ sensory modalities. Armadillos likely have limited vision [84,85,102], but compensate for this with strong olfactory senses [99] which could be incorporated into PRT while also serving as a form of sensory EE. For example, target training programmes may use food-based rewards; for armadillos, favoured food items, such as mealworms, could be used as reinforcers to encourage armadillos to utilise their enclosure spaces, or for transportation (e.g., crate training), thereby negating the need to handle individuals, potentially reducing stress. Additionally, target training incorporates elements of occupational EE by promoting problem-solving. Limited evidence indicates that armadillos show promise in completing spatial tasks [81,94], and therefore armadillos may be good candidates to trial such a PRT programme.

5. Discussion

The aim of this review is to evaluate how each of the five categories of EE together with PRT could be integrated into the care of captive armadillos, drawing on our (currently limited) understanding of their behavioural ecology to promote positive welfare outcomes. Furthermore, this paper examines how EE implementation could contribute to the broader ex situ conservation efforts for at-risk species and population sustainability for commoner species.

The key natural behaviours in armadillos, including digging and exploration, which can be encouraged in captivity through the provision of EE aligned with Bloomsmith’s categories, are illustrated in the following video footage: https://figshare.com/s/e14bf03ec7814ef2edf4 (accessed on 25 July 2025).

This footage demonstrates how the provision of logs in an armadillo enclosure encourages digging and hence the use of their powerful forelimbs, while engaging their strong olfactory senses when rooting and investigating bark crevices. Such EE can help to conserve these adaptive traits within captive populations, aligning with OPA. Concealing invertebrate prey may further promote activity and the performance of these natural behaviours, and future research should aim to determine which prey types are most effective in stimulating contrafreeloading activity.

5.1. Implications for Ex Situ Conservation

Integrating species-specific EE into husbandry and management practices can have a positive effect on welfare states by encouraging the performance of natural behavioural repertoires [103] and ARB [104], and alleviating stress [105]. The welfare benefits associated with EE provision may also have direct implications for conservation success. Preliminary research into the effectiveness of EE for armadillos found that, although anecdotal, reproductive behaviours and reproductive rates of Llanos long-nosed armadillos (Dasypus sabanicola) increased when EE was provided [57]. Further, the implementation of EE comes with varying levels of “positive” challenge, known as eustress. This is an adaptive response in which animals cope with a source of challenge, which has a positive effect on welfare states [106]. Such challenges should be ecologically relevant and specific to the species being targeted. In armadillos, this could involve providing manipulable objects within the enclosure, such as logs, which encourage the use of their forelimbs and long tongues to extract food items, including live insect prey.

In addition to promoting welfare states, encouraging behavioural resilience through EE provision in captive populations is critical to the success of wild reintroductions [107]. For example, it may help conserve behavioural responses, such as threat avoidance [108] and increase behavioural diversity [109], reflecting the range of stimuli encountered in natural environments. Due to the nature of zoo enclosures being inherently different from the wild, the variation in selection pressures can lead to behavioural adaptations in animals that do not reflect wild counterparts (e.g., reduced vigilance or altered foraging strategies). Such behavioural changes may limit the success of wild reintroductions [4]. Empirical research continues to reveal that adaptive behavioural traits can be maintained through the implementation of EE for captive populations. For example, food-based EE, including puzzle feeders, can increase the duration and diversity of foraging and exploratory behaviours [110,111] and the provision of shelters may encourage the learning of antipredator behaviours [112].

Encouraging animals to be active in the presence of people can help increase their educational value for visitors and staff. Research shows that visitor interest in zoo animals is correlated with increased activity levels [113]. For armadillos, known for low levels of activity [35], determining how to increase levels of activity may help to highlight their value for ex situ conservation initiatives, especially for vulnerable species.

As previously highlighted, armadillos can also serve as a bridge between the realities of biodiversity loss and public understanding of its underlying causes. Encouraging human–animal interactions, such as showcasing EE to promote natural behaviours, improves positive feelings of visitors towards the care received by zoo animals [114] as well as repeat visitations, indicating a positive experience during visits [115]. In a suggestion by French et al. [49], EE involving an underground tunnel system, whereby armadillos could forage underground with LED lights above ground that show the location of the individual as they manoeuvre through the tunnel, may encourage engagement between armadillos and zoo visitors. Additionally, the development of bond formations between animals and zoo staff comes with its own perceived, mutual benefits. For example, staff report greater ease in procedures such as medication administration and handling [92], alongside improved familiarity with the animals in their care [116].

Promoting human–animal interactions (HAI) may have benefits when used in conjunction with PRT. Research suggests that combining HAI and training reduces aversiveness to procedures such as handling [117], which therefore may be beneficial for armadillos that show high levels of stress when handled [52]. This may offer an opportunity to better understand species-specific learning, sensory preferences, and social tolerances, all of which currently remain poorly understood in armadillos.

Accredited and credible zoological establishments are obligated to ensure the provision of the highest possible standards of welfare for all species in their care [118], and the implementation of EE is one key step towards achieving this. However, zoo staff report that they are often restricted by their daily routines and provision of EE or PRT is often overlooked in favour of routine husbandry demands [119]. Further, some zoos may take a reactive approach to EE provision, with a disclination to provide it as a basic care requirement [8]. Currently, guidelines around EE provisions for armadillos are scarce. Future research should therefore focus on monitoring the long-term impacts of EE for armadillos across species and institutions to determine welfare impacts.

Where possible, it is imperative to maximise conservation impact through collaboration across zoos, conservation organisations, and in situ programmes, thereby broadening understanding of species-specific needs in both captive and wild contexts. This is particularly beneficial for zoo species that are considered less charismatic [120], such as armadillos, and can be supported through a OPA [6], which integrates wild and captive knowledge to promote conservation initiatives and emphasise their ecological roles and unique adaptations, whilst encouraging visitor engagement. Aligning management practices of zoo armadillo populations with the behavioural requirements of wild populations may enhance individual welfare and ensure the development and maintenance of species-specific behaviours critical for survival. Figure 2 demonstrates how OPA can be applied to enhance welfare and conservation efforts for armadillos. Cross-institutional collaboration promotes integration of wild knowledge into captive care and the use of zoo-based information to support in situ conservation, enabling the identification of species-specific needs aligned with natural behavioural ecology while fostering capacity building within relevant organisations [121], such as the IUCN SSC Anteater, Sloth and Armadillo Specialist Group, ASASG (https://xenarthrans.org/). Such metapopulation management, which values all populations across contexts, supports improved welfare and conservation outcomes and can establish a feedback loop between all stakeholders that continually refines armadillo husbandry and management practice.

5.2. Knowledge Gaps and Future Directions

While this review has addressed the role of EE in armadillo husbandry, other aspects of care are still poorly understood. Developing species-specific EE requires an understanding of species-specific behavioural ecology and identification of natural behaviours that should be encouraged [5]. Therefore, future research should focus on collecting baseline behavioural data for captive and wild individuals, particularly in species commonly held in zoos (e.g., nine-banded and three-banded armadillos) to ensure that husbandry practices reflect the behavioural and ecological needs of each species.

This can be facilitated through inter-institutional collaboration to increase sample sizes and therefore improve the validity of evidence-based practice. Reporting findings across institutions provides a more representative understanding of species’ behavioural responses, particularly for armadillo species that are scarcely housed in zoo environments. Such research provides insight into how species may respond to captive environments, and which enclosure design features promote animal health and welfare [122]. Multi-zoo studies can identify interspecific behavioural differences, provided that standardised methodologies for data collection are followed.

Ethograms are useful for behavioural studies, providing clear, standardised definitions of species-specific behaviours [123,124] and providing an evidence base for conservation action by showing how species adapt to environmental and management challenges [125]. Standardised ethograms also facilitate data comparability across observers, populations, and institutions, improving the repeatability and reliability of research [46], whilst supporting clearer behavioural interpretation [126]. Ethograms are also essential for inter-observer reliability testing, reducing subjectivity and ensuring that behavioural data are robust [127]. However, for armadillos, published ethograms are limited and have only recently become available for certain species [35,128]. Time-activity budgets for wild populations are similarly scarce, with most data focused on nine-banded armadillos, leaving other species underrepresented. Such data are useful for informing enclosure design, EE provision, and husbandry protocols to align these with species’ needs. Comparisons between wild and captive behavioural data can provide insights into behavioural flexibility and how well species may cope in zoos [129]. As we want species to do more than just cope, such evidence-based approaches (i.e., those that are built on strong behavioural data) support better practices management that move species towards thriving rather than just surviving. Thus, future behavioural investigations should aim to adopt existing ethograms as benchmarks and work toward developing species-specific behavioural metrics and welfare assessments.

Given the limited representation of certain armadillo species across subfamilies in zoos, collaboration between institutions is essential to ensure meaningful comparisons between ecologically similar groups. Future research should therefore encourage multi-institutional collaboration. Partnerships with in situ conservation programmes (such as the ASASG) and targeted field studies will also help determine the behavioural needs for underrepresented taxa, ensuring that ex situ management aligns with natural behavioural baselines.

This review has identified several key knowledge gaps. To address these, future empirical research should consider the following questions, outlined in

Table 1. Suggested research questions to develop our understanding of armadillo needs and guide captive husbandry and management practice.

Key Research Question	Data Collection Approach	Relevance to Captive Management	References
What is the wild ecology of armadillos?	Conduct longitudinal field studies to investigate seasonal variation in behaviour across armadillo species.	Inform husbandry, management, and enclosure design aligned with species-specific needs	Superina [55] Rodrigues et al. [64] Desbiez and Atiias [74] Maccarini et al. [130]
What are baseline wild time-activity budgets in armadillos?	Collect wild behavioural data using standardised approaches and ethograms	Identify behaviours that should be supported or promoted in captivity	Desbiez et al. [17] Maccarini et al. [130]
Which forms of EE are most effective for armadillos?	Conduct long-term studies on the effectiveness of EE types from each of the five main categories	Ensure that EE provisions meet the behavioural needs of captive armadillos	Kelly and Rose [35] Cortés Duarte et al. [57]
What are the cognitive abilities of armadillos?	Use spatial learning tasks with zoo-housed individuals across species	Tailor EE complexity, support cognitive stimulation, and encourage eustress	Vincent and Vonk [84]
Can armadillos serve effectively as ambassador animals for conservation and welfare education?	Measure visitor engagement, learning, and conservation attitudes before and after armadillo encounters via surveys and behavioural observations	Providing EE can enhance visitor engagement, while integrating wild knowledge helps demonstrate the ecological role of armadillos	Spooner et al. [69] Martin et al. [72]

. These will serve as a foundation for guiding further investigation and advancing our understanding of armadillo species’ behavioural needs.

6. Conclusions

A structured and holistic approach to EE, guided by species-specific needs, is critical for promoting positive welfare outcomes and supporting natural behaviours, particularly in understudied species such as the armadillos. By combining Bloomsmith’s five EE categories with PRT, institutions can target armadillos’ key sensory modalities while promoting adaptive behaviours, though future research must investigate which EE best aligns with armadillos’ sensory modalities. Applying the principles of OPA could enhance welfare by ensuring that EE prioritises adaptive behaviours such as foraging, digging, rooting, and burrow construction, thereby maintaining ecologically functional repertoires in captive insurance populations and strengthening their viability for future reintroduction initiatives.

The educational role of species held in zoos can strengthen public understanding and support for ex situ conservation initiatives [131]. This is particularly true for more elusive species such as armadillos, so some of the outlined examples of EE provided here can guide institutions in enhancing the conservation and educational value of armadillos in zoo exhibits. There may be much to still uncover regarding the success of EE and PRT when implemented into husbandry and management regimes for captive armadillos. We therefore urge researchers to continue investigating the effectiveness of EE for all armadillo species under human care to promote maximum beneficial outputs for animals, for zoo objectives, and for the personnel involved in their care.