Ground Breaking Study Explores Cetacean Welfare in Zoos and Aquariums

When it comes to animal welfare, it’s important to routinely challenge commonly held beliefs in an effort to ensure animals always receive the best possible care. A groundbreaking cetacean welfare study did just that over the last three years and recently published their findings. This is the largest-ever multi-institutional study on the impacts that habitat, environmental enrichment, and animal training have on cetacean welfare inside accredited zoos and aquariums.

The Chicago Zoological Society which manages Brookfield Zoo in Brookfield, Ill.; University of California, Irvine; Portland State University; and University of Florida College of Veterinary Medicine; led the study, which included 43 accredited organizations in seven countries.

In 2018 and 2019, scientists and animal caretakers collected data from 216 common and Indo-Pacific bottlenose dolphins, 13 beluga whales, and eight Pacific white-sided dolphins. The study analyzed welfare from the different lenses of habitat, training programs, environmental factors, and personal demographics (like the age and sex of the dolphin or whale). The findings themselves may not be particularly surprising to most people who have cared for these animals for years, but the results created scientific and data-driven evidence to help shape best practices when it comes to the welfare of dolphins and whales in zoos and aquariums.

“Animal welfare is an interesting concept in that there’s two parts. One is the scientific part. We as scientists can measure almost anything. But at some point, you have to make the judgement call: Is this good enough? Are these animals really thriving?” said Dr. Jill Mellen, a scientist who helped design the study.

“Animal welfare research is not as cut and dry. For a long time, scientists had a hard time assigning human terms to animals. Being anthropomorphic is something we need to do cautiously, but there are some parallels,” she added. “If you’re only looking for negative welfare, you’re only going to find indications of negative welfare. In the last 20 years, we’ve looked for indications of both positive and negative welfare.”

As part of the study, Dr. Lance Miller, the vice president of conservation science and animal welfare research at the Chicago Zoological Society, led a group of scientists (including Dr. Lisa Lauderdale, also from the Chicago Zoological Society; Dr. Jill Mellen, Portland State University; Michael Walsh, DVM, from University of Florida College of Veterinary Medicine; and Dr. Douglas Granger, professor and director of the Institute for Interdisciplinary Salivary Bioscience Research at the University of California, Irvine) to examine the welfare of dolphins and whales. Scientists collected physiological evidence (blood and fecal tests), evaluated known indicators of welfare like cortisol, and tracked behavior with MTags to look at how far dolphins swam and how much energy they used.

“In terms of animal welfare, we’re thinking about their mental health as well,” said Miller. “The general public has a perception that dolphins need a large habitat because they think of them living in the wild. But if you’re a human, would you rather live in a cozy house with lots of things to do or a large place with nothing to do?”

Mellen likened their approach to the study to taking a dog to the vet. In that scenario, a veterinarian conducts a physical. Then, the vet will ask questions about the dog’s behavior to help determine the dog’s emotional state. This creates a larger picture of the animal’s welfare and personality.

The study helped set parameters for enrichment programs so caretakers can compare and contrast their own animals’ health and welfare.

“What goes into making a happy dolphin?” asked Mellen. “Things like their enrichment programs, size and complexity of their habitats, management style, whether they’re all together or whether there are subgroups, the training schedule, interaction programs, age and sex ... We looked at it all and asked what correlates with our measures of an animal thriving?” They examined known behaviors of positive welfare as well as negative behaviors like route tracing, which is similar to pacing in the water.

After gathering all of this information over two years, they put it into a computer that created multiple correlations. They found that habitat size was not a strong indication of dolphins thriving, and that management style and enrichment were more important.

“The most significant finding in my opinion was that our engagement with the animals through positive reinforcement based training and environmental enrichment far outweighs the size and shape of the habitat. This did not surprise me based on my experience working directly with the animals,” said Eric Gaglione, vice president of zoological operations at Georgia Aquarium in Atlanta, Ga. The Aquarium’s dolphins and belugas contributed blood and fecal samples to the study. Two of their dolphins wore MTags periodically over a course of two five-week periods.

“This study has helped to refine our eye on the animals with a keener understanding of what contributes to enhanced welfare. Our team is taking what was learned to further enhance welfare states by striving for greater diversity in species appropriate behavior through novel environmental enrichment practices and creative daily management of the animals in their various habitats and social groups,” he added.

Data from the 43 institutions worldwide were used to create a new set of research tools, including an iOS app called ZooPhysioTrak, which will serve as a comprehensive database of health and welfare biomarkers. ZooPhysioTrak provides veterinarians and cetacean caretakers with the “normal” health and welfare references for test results (primarily blood and fecal tests) as found in the 216 dolphins studied. ZooPhysioTrak now gives cetacean managers unprecedented access to this information, which can help them monitor dolphin health much more closely.   

“This is the first time I had reference ranges to compare our animal’s fecal metabolite concentrations. These are welfare indicators that we use here at Brookfield Zoo, among many other indicators, to develop a holistic look at each dolphin’s individual welfare,” said Rita Stacey Vondra, curator of marine mammals at Brookfield Zoo.

Vondra and her team played a significant role in the dolphin behavioral study. They helped to fine-tune the MTag process with their dolphins, who helped “test drive” the devices. The staff worked hard to help the dolphins become comfortable with the tags, which involved working with each dolphin’s individual personality and managing the social aspects of the group. When the dolphins weren’t wearing MTags, they were being videoed so scientists could later study their behavior visually.

After participating in the study, several zoos and aquariums were eager to compare and contrast their findings.

“My team and I were excited to digest the results of the Cetacean Welfare Study to enhance the wellbeing of the animals in our care. We were pleased to hear that many of the findings of the study were already our practice here,” said Vondra. The study showed that regularly scheduled care and training sessions improved behavioral diversity and swimming distance. It also recommended splitting dolphins into different groups during the day and then reuniting them. Both are common practice at Brookfield Zoo already. To create more enrichment opportunities, the team now has a dedicated team member whose job it is to introduce a new enrichment item regularly and to change up the current enrichment rotation on an even more frequent schedule.

This study was significant on the world stage for several reasons. It created massive amounts of data that will provide new resources for welfare monitoring, cetacean management, and enrichment. It showed that the quality of care directly impacts welfare more so than other factors like habitat. This study was also significant because of its size. Inter-facility studies are expensive, difficult, and logistically overwhelming, so to have this many facilities working together to monitor and share information was groundbreaking.

Given all of this, it may come as a surprise that many dolphin researchers and cetacean managers involved didn’t uncover anything unexpected.

“When you spend so much time with animals, just like people, you get to know them on a very close and personal basis,” said Vondra, who has spent three decades working with bottlenose dolphins. In that time, she has developed a complex human-animal relationship. “You become familiar with their normal behavior, what excites them, you get to know their likes and dislikes, and can recognize when there are departures from normal behavior. Having our dolphins thrive and live their best lives is our duty and our responsibility.”

Lance Miller agreed.

“I’ve spent a lot of time watching dolphins, so the results weren’t that surprising,” he said. “Really, the best thing about this study is how strongly it demonstrates the collective interest in accredited zoos and aquariums wanting to do what’s best for their animals.”

The collection of studies can be seen in the peer-reviewed journal PLOS One. Funding for this project was provided through a National Leadership Grant from the Institute of Museum and Library Services (IMLS), Grant #MG-30-17-0006-17, with additional support from partner facilities.

Hero photo: Merlin, a 7-year-old bottlenose dolphin at Brookfield Zoo, was one of 216 common and Indo-Pacific bottlenose dolphins who wore a bio-logging device or MTag during the Cetacean Welfare Study’s data collection period. Credit: ©Chicago Zoological Society

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