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Interview with San Diego Zoo’s Animal Enrichment Expert—Dr. Lance Miller

Contributing Editor Dr. Jordan Schaul interviews environmental enrichment expert Dr. Lance Miller of San Diego Zoo Global’s Institute for Conservation Research.

Today, zoos adhere to strict environmental enrichment protocols to ensure that the animal ambassadors in their respective collections are stimulated and encouraged to perform natural behaviors. Enrichment programs are carefully planned and science-based, just as nutrition or preventive health care programs are created following rigorous scientific study of animals in the wild and captivity. In fact, Association of Zoo and Aquarium (AZA) accredited zoos must comply with enrichment standards set forth by the association.

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I turned to Dr. Lance Miller, a scientist at the San Diego Zoo’s Institute for Conservation Research, to find out more about how carefully planned zoo enrichment programs are for eliciting certain natural behaviors and for mitigating some of the aberrant behaviors that may be artifacts of captive life.


Jordan: Many zoos today have enrichment coordinators on staff. These individuals are tasked with developing programs that encourage animals to be active. San Diego Zoo Global actually has dedicated personnel that help implement evidence-based environmental enrichment programs in all animal areas. Much of this starts with scientists like yourself, who monitor activity budgets and behavioral repertoires to get some idea of how to best incorporate programs of this nature in an effort to promote healthy behavior and appropriate activity levels in captive wildlife. Can you elaborate on this process.

Lance: We are interested in putting a scientific framework around environmental enrichment for zoo animals.  This includes conducting enrichment preference assessments to determine the preferred enrichment for different species and individuals within that species.  We are also looking at how environmental enrichment affects behavior over a twenty-four period and if we can use short ten minute preference assessments to predict interactions over an entire day.  The ultimate goal is to ensure we are meeting the behavioral needs of the animals to ensure every individual is thriving under our care.

Jordan: In one of your papers, you discuss the impact of predictability of the development of stereotypic behavior in captive animals, particularly carnivores such as big cats, bears and wild canids. Can you first define what a stereotypy is and why and how you try to mitigate these behaviors in captive animals.

Lance: Scientists have been debating the definition of stereotypic behavior for years.  While important to have a concise definition that can be used for behavioral research, the main purpose is to ensure we are taking the best possible care of the animals.  Anytime stereotypic or abnormal behavior is observed within a zoo, the behavior should be investigated to determine the root cause.  While behavior such as pacing in carnivore species has often been attributed to boredom, research has shown that predictability and lack of control over a positive situation (e.g., receiving food) or inability to interact with conspecifics visible in other exhibits can increase this behavior.  Only through sound science will we better understand these behaviors and be able to ensure our animals have the best life possible.

Jordan: I was often taught as a zoo keeper that the best enrichment for an animal in captivity is a conspecific—another individual of that species. But you have learned that conspecifics can both reduce levels of stereotypic behavior, as well as increase these stress response behaviors. Can you discuss generally the significance of social enrichment on the well-being of zoo animals and more specifically your work on tigers?

Lance:  I agree completely that for a social species, having a conspecific to interact with is likely the best enrichment for that animal.  One of the questions we have been trying to answer is how does having the ability to view conspecifics without being able to interact with them affect behavior.  We examined this type of situation with tigers that had the ability to view tigers in neighboring exhibits which was part of their current management.  By putting up visual barriers between the exhibits we were able to significantly reduce pacing which suggests having the ability to view conspecifics without interacting with them can be a negative situation that leads to pacing.  We are currently working on some other studies with additional species to determine if this pattern holds true for both solitary and social species.

Jordan: What does the future hold for research into zoo animal enrichment and what direction is the San Diego Zoo moving with regard to developing more evidence-based environmental enrichment programs?

Lance:  We have been working with the University of California, Los Angeles to develop an online enrichment documentation system that would allow animal care staff the ability to track real-time the enrichment provided to the animals and the effect of that enrichment on behavior.  The San Diego Zoo Global animal care staff are extremely dedicated to providing the highest quality of care for the animals within the collection and our goal is to provide them with the tools to ensure every animal has the best life possible.