Resilience in Zoo Animals: What It Means, How It Relates to Welfare, and How We Can Build It

Introduction

Resilience has become a prominent topic in zoo and aquarium welfare science, and for good reason. For those working with animals under managed care, it's increasingly clear that it’s not just the current welfare state that matters but also how animals cope with challenges over time. This also means the animals need to be given challenges to overcome, which must be carefully designed.

A recent seminar hosted by the Association of Zoos and Aquariums (AZA) brought renewed focus to this topic, with welfare scientist Jessica Whitham presenting insights from her and Lance Miller’s comprehensive review on resilience (J. Zool. Bot. Gard. 2025, 6(3), 48). Their work provides a helpful framework for understanding what resilience is, how it connects to welfare, and how we can actively support it.

This blog brings together these ideas across four themes:

1. What resilience means

2. How resilience and welfare align, and how they differ

3. Practical strategies for building resilience in animals under human care

4. Measuring resilience

A giraffe at Kolmarden Djurpark, where this exhibit can only be viewed by visitors sitting in gondolas that move over the enclosure. This allows a much larger and more diverse habitat to be provided, whilst also ensuring visitor viewing of the animals.

1. What Do We Mean by “Resilience” in Animals?

Whitham and Miller define resilience as:

“The capacity of the animal to be minimally affected by a disturbance or to rapidly return to the physiological, behavioural, cognitive, health, affective, and production states that pertained before exposure to a disturbance.”

In everyday terms, resilience describes how well an animal copes with a stressor and how quickly it returns to baseline.

This concept aligns closely with welfare because animals who cope effectively and recover quickly are generally experiencing better welfare states. Many of the factors suggested to promote good welfare—such as social play, enrichment engagement, problem-solving opportunities, and behavioural diversity—are also associated with stronger resilience.

In studies across multiple species, these variables correlate with quicker and more complete recovery from mild stressors.

A key takeaway is that resilience is not fixed i.e. it is not inherited. It is influenced by experience and can therefore be built, shaped, and strengthened.

2. How Do Resilience and Welfare Align or Differ?

While closely connected, resilience and welfare are not the same.

Welfare: A State in the Present

Animal welfare is generally understood as the animal’s current state of being i.e. how it is coping with its environment right now, and the balance of its positive and negative affective states. Welfare is multidimensional and will change in response to internal or external factors.

Resilience: A Capacity for the Future

Resilience, by contrast, is about capacity. It reflects the animal’s ability to remain minimally affected by challenges and to recover quickly afterwards.

Where They Align

Good welfare can clearly foster resilience. Animals experiencing:

• Positive affective states

• Enriched, stimulating environments

• Strong social bonds

…are often better equipped to cope with future stressors. Likewise, encountering manageable challenges can increase positive affect, maintain behavioural flexibility, and strengthen social relationships, therefore feeding back into improved welfare.

Where They Differ

However, the relationship is not perfectly symmetrical.

An animal may experience good welfare but have low resilience. For example, an animal living in a highly predictable, stable, comfortable environment might show excellent welfare indicators, until something changes. Without prior exposure to manageable challenges, it may lack coping strategies or behavioural flexibility, resulting in heightened or prolonged stress responses. Furthermore, zoo animals living in highly predictable environments without mild stressors are likely to show a limited repertoire of natural behaviours, given the wild environment is full of stressors and challenges.

Conversely, an animal may appear resilient while still experiencing poor welfare. Some individuals can appear to “cope” through physiological adaptation or behavioural suppression while still living under chronic stress, negative affective states, or biologically costly conditions. In such cases, resilience to stress does not necessarily indicate positive welfare.

In summary:

• Welfare is the state now.

• Resilience is the capacity for tomorrow.

Understanding both allows us to create environments that support not only good current welfare but also long-term quality of life and adaptability to change.

Social competition for food may be an appropriate challenge that zoo animals should regularly encounter, although should be closely monitored and managed.

3. How Can We Build Resilience in Zoo and Managed Animals?

At the highest level, resilience is supported by daily management practices that promote agency, adaptability, and positive social experiences, as all of these will help an animal overcome mild stressors when they arise. These principles apply across species and settings, from zoos to sanctuaries to farms and laboratories.

More specifically, resilience-building strategies include providing:

• Cognitive Enrichment

Enhances problem-solving ability and behavioural flexibility. Examples: puzzle feeders, experiential enrichment (e.g. devices and actions to mimic a hunt sequence), autonomous enrichment that can be controlled and varied by the animal e.g. remote-sensor devices.

• Agency and Control

Animals with more predictable, controllable environments show lower stress reactivity. This doesn't mean the environment shouldn't vary, but that the animal has some level of choice over changes and how it can respond to them. Examples: autonomous enrichment, choice of housing/social group/enclosure/food items, genuine choice in training sessions (i.e. where food is also offered for not participating).

• Appropriate Challenge

Mild, manageable stressors can build an animal's coping skills, when well-designed and species-appropriate. Examples: gradual exposure to novelty, controlled unpredictability, brief food withholding for some species (where ethically and biologically appropriate), species-appropriate social group changes.

• Social Buffering

Affiliative social partners can reduce the intensity and duration of stress responses. Examples: stable social groups, facilitated introductions, supporting natural social structures.

• Environmental Complexity

Encourages exploration, autonomy, and adaptive behaviour, as well as physical fitness which likely will help an animal feel like it can cope. Examples: multi-zone habitats, variable substrates, strategic enrichment layouts that encourage movement and choice but that can also be varied, enrichment infrastructure to facilitate daily, temporary and semi-permanent additions to the environment.

4. Measuring Resilience

There is much literature describing measuring the stress response of animals, especially in farm and laboratory settings, but few that research wild animals in zoos. In addition, few studies track the animals over time to understand how exposure to the stressor might impact their response to the subsequent challenge. Compared to holistic welfare assessments, resilience is likely to be more straightforward to measure, as it focuses on:

• The magnitude of the stress response

• The speed and completeness of return to baseline

This may involve behavioural observations, physiological indicators (e.g., glucocorticoids), or performance in cognitive tests (e.g. cognitive bias). Baseline measurements are needed before any challenge is introduced, and are likely to be needed for individual animals as opposed to groups.

Challenging animals to problem-solve to access their food, especially when they have full agency over the task an outcome, is a great way of increasing resiliency

Conclusion

Resilience is emerging as a powerful concept within animal welfare science. It reminds us that while comfort and stability are important, animals also benefit from experiences that help them adapt, recover, and cope with change.

By incorporating mild, manageable challenges into well-designed environments—and ensuring animals have agency, social support, and opportunities to learn—we can strengthen both resilience and long-term welfare.

We will continue exploring these ideas here and on our Learning Platform with our Members.

And if you haven’t already, we recommend reading Whitham and Miller’s review for a deeper dive into this topic (J. Zool. Bot. Gard. 2025, 6(3), 48).