Environmental Enrichment for Animals in Captivity
Introduction
Applied animal behavior (ZY3020): Environmental enrichment for animals in captivity.
Estimates suggest that 26 billion animals (across 10,000 species) are held in captivity, either on farms or in zoos (Mason, 2010).
These captive environments present unique challenges and opportunities for managing animal behavior and welfare.
Understanding the nuances of captivity is crucial for promoting ethical and sustainable practices.
Question: What are the benefits and limitations of keeping wild animals in captivity?
The Scope of Captivity
Captivity spans a wide range of contexts, from agricultural settings to conservation facilities.
Each context has specific implications for animal welfare and enrichment strategies.
The sheer number of animals in captivity underscores the importance of effective management and enrichment practices.
Benefits and Limitations of Captivity
Benefits:
Animals receive consistent access to food, water, and veterinary care, ensuring their basic needs are met.
They are protected from the immediate threats of conflict and predation, enhancing their safety.
Generally, they live longer compared to their wild counterparts (though this varies among species due to differences in natural lifespan and environmental stressors in captivity).
They may be healthier due to regular monitoring and treatment of diseases and injuries.
Captivity can enable more successful breeding programs, contributing to species conservation efforts.
Captivity enables humans to study and learn about wild species under controlled conditions, advancing scientific knowledge and conservation strategies.
Limitations:
Many unnatural stressors are inherent in captive environments, such as limited space and artificial social groupings.
There is evidence of compromised welfare, including behavioral and physiological indicators of stress.
This indicates that psychological and physiological needs are often not fully met, leading to reduced quality of life.
Definition of Environmental Enrichment
Environmental enrichment is defined as:
An animal husbandry principle that seeks to enhance the quality of captive life by identifying and providing environmental stimuli necessary for the optimal psychological and physiological well-being of animals in captivity.
An improvement in the biological functioning of captive animals resulting from modifications to their environment through changes to the structure and content of enclosures.
It is a multidisciplinary field involving applied ethology, ecology, natural history, animal husbandry, and zoo design.
Core Principles of Environmental Enrichment
The central aim is to create captive environments that stimulate natural behaviors and reduce stress.
Effective enrichment should address the specific needs and preferences of each species.
Integration of various disciplines ensures a holistic approach to improving animal welfare.
Brief History of Environmental Enrichment
Robert Yerkes (1925):
Suggested that the greatest possibility for improvement in provisions for captive primates lies in the invention and installation of apparatus that can be used for play or work.
Hediger (1950):
Stated that one of the most urgent problems in the biology of zoological gardens arises from the lack of occupation of the captive animal.
Hal Markowitz (1982):
Considered the "father of enrichment."
He created devices in white-handed gibbon (Hylobates lar) enclosures that encouraged brachiation behavior.
Key Milestones in Enrichment History
Early recognition of the importance of activity and stimulation for captive animals.
Markowitz's work highlighted the potential of environmental design to promote natural behaviors.
These historical insights paved the way for modern enrichment practices.
Goal of Environmental Enrichment
Increase behavioral diversity by providing opportunities for a wider range of activities.
Reduce abnormal behavior, such as stereotypies, that indicate poor welfare.
Increase the range of 'normal' (wild/desired) behavior patterns to better reflect natural behaviors.
Increase positive utilization of the environment, encouraging animals to explore and engage with their surroundings.
Increase the ability to cope with challenges and pressures by building resilience.
Stimulate and challenge animals mentally and physically.
Measurable Outcomes of Enrichment
Enrichment aims to create environments that promote both physical and psychological well-being.
Successful enrichment can be assessed through changes in behavior and physiological indicators.
The ultimate goal is to enhance the overall quality of life for captive animals.
Stereotypical Behaviors
The most well-known behavioral problem in captivity.
Defined as "repetitive, unvarying, and apparently functionless behavior patterns" (Mason, 1991).
The performance of these behaviors is an important indicator of reduced welfare in captivity.
Can be a "scar" from previous suboptimal environments, so care is needed to address underlying causes.
Mason & Latham (2004) found that 68% of environments associated with stereotypies are associated with diminished welfare.
The Significance of Stereotypies
Stereotypies are often a sign of chronic stress or unmet needs.
They can persist even after the environment is improved, indicating long-lasting effects.
Addressing stereotypies requires a multifaceted approach, including enrichment and management strategies.
Causes of Stereotypical Behaviors
Frustration-induced: motivational frustration, fear, or physical discomfort can trigger stereotypies.
Malfunction-induced: central nervous system abnormalities may also contribute to these behaviors.
Types of Stereotypical Behavior
Pacing, body-rocking, licking, self-biting are common examples.
Different taxa show differences in the primary types of stereotypical behavior they perform:
Carnivores: Locomotory stereotypies, such as pacing.
Ungulates: Oral stereotypies, such as tongue rolling.
Primates: Oral and locomotory stereotypies.
Enrichment and Its Effects
GAP analysis – 744 articles (De Azevedo et al., 2007) highlights the breadth of research on enrichment.
Swaisgood & Shepherdson (2006) found that enrichment works well with carnivores, primates, and other species, showing a reduction in stereotypical behavior by .
How do we measure the success or failure of enrichment?
Evaluating Enrichment Effectiveness
Measuring the impact of enrichment is crucial for optimizing strategies.
Behavioral observations, physiological measurements, and welfare assessments can provide valuable insights.
Adaptive management involves continuously refining enrichment based on evaluation results.
Behavioral Evidence of Improvement
Reduction of stereotypies, indicating reduced stress and improved welfare.
Reduction of injurious behavior, such as self-harm, suggesting better coping mechanisms.
Reduction of fear and reactivity to stresses, demonstrating increased resilience.
Reduction of aggressive behavior, promoting social harmony.
Increased behavioral diversity, reflecting a wider range of natural activities.
Increased space usage, indicating greater exploration and engagement with the environment.
Increased learning ability, suggesting enhanced cognitive function.
Indicators of Successful Enrichment
Observing these behavioral changes provides valuable insights into the effectiveness of enrichment.
A combination of indicators offers a comprehensive assessment of animal well-being.
The goal is to create environments that support a full range of natural behaviors.
Types (Forms) of Environmental Enrichment
Food-based enrichment, utilizing feeding strategies to stimulate foraging behaviors.
Physical enrichment, involving modification of the enclosure to increase complexity and activity.
Sensory enrichment, providing visual, olfactory, and auditory stimuli to engage the senses.
Social enrichment, facilitating interactions with conspecifics or other species.
Cognitive enrichment, challenging animals with problem-solving tasks and mental stimulation.
Categories of Environmental Enrichment
Intrinsic (Self-driven): The device itself has some inherent value = NON food related.
Extrinsic (Reward driven): The device itself is the reward = Food related.
Tarou and Bashaw (2007)
Comprehensive Enrichment Strategies
It’s important that enrichment categories can be combined to create comprehensive strategies tailored to the specific needs of the animals.
Additional Goals of Enrichment
Not only for reducing stereotypical behavior but for stimulating wild behaviors and improving physical condition, mental well-being, and encouraging behaviors necessary to survive in the wild.
Long-Term Objectives of Enrichment
Enrichment programs should aim to equip animals with the skills and behaviors needed for successful reintroduction, if applicable.
A holistic approach to enrichment considers the physical, psychological, and social needs of each animal.
The ultimate goal is to create environments that promote thriving, not just survival.
Assessment of Enrichment Experiments: S-P-I-D-E-R Framework
Setting goals: Define specific, measurable objectives for the enrichment program.
Planning: Develop a detailed plan outlining the strategies and resources needed.
Implementing: Put the enrichment plan into action, ensuring proper execution.
Documenting: Record observations and data to track the impact of enrichment.
Evaluating: Assess the results and determine whether the goals have been achieved.
Re-adjusting: Make necessary modifications to improve the effectiveness of the enrichment program.
The S-P-I-D-E-R Framework
This framework provides a structured approach to designing and evaluating enrichment programs.
It emphasizes the importance of continuous improvement and adaptation.
By following these steps, practitioners can ensure that enrichment efforts are effective and sustainable.
Designing Enrichment
What factors do we need to consider in the design process?
Species-specific needs: Understand the unique behavioral and physiological requirements of each species.
Purpose of the enrichment: Define the specific goals and objectives of the enrichment.
Materials used: Select safe, durable, and appropriate materials for the enrichment device.
Cost: Consider the budget and identify cost-effective enrichment options.
Safety: Ensure that the enrichment device is safe for the animals and does not pose any risk.
Key Considerations for Enrichment Design
Enrichment should be tailored to the natural behaviors and preferences of the species.
Safety is paramount, and potential hazards should be carefully evaluated.
Cost-effectiveness and sustainability are important factors for long-term implementation.
Food-Related Enrichment
Commonly used in captivity due to its effectiveness in stimulating natural behaviors.
Includes scatter feeding, feeding devices, replicating wild hunting and feeding situations, changing feeding temporally and spatially, hiding food, etc.
Examples:
Electronically controlled feeders for red foxes (Kistler et al., 2009) and tigers (Jenny & Schmid, 2002) to mimic natural feeding patterns.
Feeding tigers, lions, and leopards with intact carcasses (McPhee, 2002) to promote natural hunting behaviors.
Live fish for fishing cats (Shepherdson et al., 1993) to encourage fishing skills.
Multiple feedings of hidden food for leopard cats (Shepherdson et al., 1993) to stimulate foraging.
Lure systems for cheetahs (Williams et al., 1993; Quirke et al., 2013) to encourage pursuit and hunting behaviors.
Benefits of Food-Related Enrichment
Stimulates natural foraging behaviors, reducing boredom and increasing activity.
Provides mental stimulation and problem-solving opportunities.
Enhances physical fitness and coordination.
Sensory Enrichment
Captive environments can lack a variety of visual, olfactory, and auditory cues, leading to sensory deprivation.
Examples:
Use of nutmeg, catnip, and body odor of prey to black-footed cats (Wells & Egli, 2004) increased levels of activity and exploring.
Cloths impregnated with odors for gorillas resulted in no behavioral changes (Wells et al., 2007), highlighting the importance of species-specific enrichment.
Broadcast territorial song duet of wild Lar gibbons to a captive group – stimulated response by captive group (Shepherdson et al., 1989).
Use of country and classical music to reduce stereotypical behavior in Asian elephants (Wells & Irwin, 2008).
The Role of Sensory Stimulation
Sensory enrichment can mitigate the effects of sensory deprivation in captivity.
It can stimulate natural behaviors and promote psychological well-being.
The effectiveness of sensory enrichment depends on the specific needs and preferences of the species.
Structural Enrichment
Increased complexity of enclosure – linked to sensory enrichment through provision of varied stimuli.
Examples:
Providing hiding places for leopard cats resulted in decreased stress levels (Moreira et al., 2007).
Provisioning of lion-tailed macaque enclosures with ropes, logs, and feeding baskets resulted in decreased levels of self-biting behavior (Mallapur et al., 2007).
Reintroduction projects – golden lion tamarins – released but died due to lack of ability to climb on moving structures – structural enrichment in captivity fixed the problem for subsequent reintroductions.
The Importance of Structural Complexity
Structural enrichment can provide opportunities for exercise, exploration, and social interaction.
It can also reduce stress and promote natural behaviors.
The design of structural enrichment should be tailored to the specific needs of the species.
Social Enrichment
Provide animals with opportunities to perform species-specific behaviors, such as social grooming and play.
Examples:
Mixed-species exhibits to simulate wild environments like the African ungulates.
Macaques housed singly show higher levels of stress and abnormal behavior, highlighting the importance of social interaction.
Male cheetahs maintained in groups showed less stereotypical behavior (Quirke et al., 2013).
The Benefits of Social Interaction
Social enrichment can reduce stress, promote natural behaviors, and improve overall welfare.
It is particularly important for social species that rely on group interactions for survival.
The design of social enrichment should consider the social dynamics and needs of the species.
Cognitive Enrichment
Providing animals with a mental challenge in the form of working for food or the addition of features that require problem-solving – use in combination with feeding/structural enrichments.
Examples:
Puzzle feeders in pandas (Swaisgood et al., 2001) to stimulate foraging and problem-solving skills.
Walnuts coated with non-toxic glue and sawdust increased foraging time in capuchin monkeys (Visalberghi & Vitale, 1990), providing a challenging foraging task.
Tiger pole feeding to encourage natural hunting behaviors.
Use of training for enrichment and management, enhancing mental stimulation and cooperation.
Auditory control enrichment (Markowitz et al., 1995) - Sabrina the leopard.
The Role of Cognitive Challenges
Cognitive enrichment can enhance mental stimulation, promote problem-solving skills, and improve overall welfare.
It is particularly beneficial for intelligent species that require mental challenges to thrive.
The design of cognitive enrichment should consider the cognitive abilities and interests of the species.
Natural Enrichment & Further Reading
Major increase in calls for natural enrichment – less toys, unnatural objects – research natural history and use this for enrichment ideas.
Suggested Journals:
Zoo Biology
Applied Animal Behaviour Science
Journal of Zoo & Aquarium Research (JZAR)
Books:
Zoo Animals, Behaviour, Management and Welfare (Geoff Hosey, Vicky Melfi, Sheila Plankhurst)
Second Nature: Environmental Enrichment for Captive Animals (David Shepherdson, Jill Mellen, Michael