Multi-institutional study dives deep into cetacean welfare

Dolphins wear activity devices so researchers can gauge how they use their environment
Published on May 29, 2019

Some bottlenose dolphins are wearing superhero capes at Brookfield Zoo in Brookfield, Illinois, a suburb of Chicago. At least, that's what the caretakers call the activity monitoring devices the dolphins wear for research.

"It (the device) is basically the equivalent of a dolphin Fitbit or dolphin Apple Watch," said Lisa Lauderdale, PhD, a postdoctoral fellow in the Animal Welfare Research department for the Chicago Zoological Society, which manages Brookfield Zoo.

Elizabeth Lee and Tapeko
Elizabeth Lee, senior animal care specialist, works with Tapeko, 37. The bottlenose dolphin is participating in one of the largest-ever, multi-institutional studies to quantify how physical habitat, environmental enrichment, and animal training impact the welfare of cetaceans in zoos and aquariums. (Photo by Kaitlyn Mattson)

The Brookfield Zoo and the Chicago Zoological Society are at the forefront of research that includes 44 facilities located across seven countries and involves 290 common and Indo-Pacific bottlenose dolphins, 20 beluga whales, and eight Pacific white-sided dolphins.

In the last 15 years, there has been a lot of attention paid to cetaceans in general, and there has been a lot of questions about their welfare. I think there has been a lot of misinterpretations, and so we decided we wanted to put some real science behind it.

Bill Zeigler, senior vice president of animal programs.
Chicago Zoological Society

The study has two main objectives: to develop reference ranges for physiologic biomarkers that can be used to assess the general health of cetaceans and to identify factors that can influence the overall welfare of bottlenose dolphins, specifically, by trying to measure activity and movement.

For dolphins, researchers are using a device called an MTag, which has suction cups specifically designed for dolphins and is worn just behind a dolphin's blowhole. It contains an accelerometer, a magnetometer, and a gyroscope to sense orientation and movement so that investigators can evaluate the energetics of the animal. There are also speed and pressure sensors to detect how fast and deep the dolphin is swimming.

The information the MTag gathers is meant to provide an overall look at how the dolphins are using their environment, said Dr. Lauderdale, one of the principal investigators on the study.

Dr. Ivaničić and Elizabeth Lee examine a dolphin
Dr. Marina Ivaničić, veterinary radiologist for the Chicago Zoological Society, and Elizabeth Lee, a senior animal care specialist, conduct a medical examination on a bottlenose dolphin at Brookfield Zoo. Medical procedures are just one component of the cetacean welfare study. (Courtesy of Chicago Zoological Society)

"You can see how much time they're spending near the top of the habitat, when they go to the bottom, how much time they spend in the middle," she said. "We can see how far they're swimming every day, how much energy they use, and then we can correlate that to the size, shape, depth of an exhibit (or habitat)."

Historically, dolphins have been seen as animals that do well in zoos and aquariums. However, the participating institutions want to put evidence behind that notion.

"In the last 15 years, there has been a lot of attention paid to cetaceans in general, and there has been a lot of questions about their welfare. I think there has been a lot of misinterpretations, and so we decided we wanted to put some real science behind it," said Bill Zeigler, senior vice president of animal programs at the Chicago Zoological Society.

Some of the questions the investigators hope to answer, according to Lance Miller, PhD, senior director of animal welfare research for the Chicago Zoological Society, include the following:

  • How do habitat characteristics impact environment use and behavior in bottlenose dolphins?
  • How does enrichment influence animal welfare?
  • How does training influence animal welfare?
  • What characteristics of the habitat and training lead to optimal welfare?

"When you think about animal welfare, (it's a scale) that goes from poor to good, and so what we want to do is figure out what things lead to optimal welfare," Dr. Miller said. "What things lead to animals being on the high end of that scale."

Bottlenose dolphin wearing and MTag
A bottlenose dolphin at Brookfield Zoo near Chicago wears a device called an MTag to measure activity level and movement. A similar device, a DTAG, has been used with wild whales. For this research, the MTag was developed by the engineering department at the University of Michigan and the Chicago Zoological Society. (Courtesy of Chicago Zoological Society)

The project is considered to be the largest of its kind, and the participating organizations seem encouraged by its scale and scope. There have been challenges along the way, including issues working across time zones and shipping equipment internationally. However, those involved are optimistic about what the results will show.

"My hope is that this study will show that the dolphins do thrive in our care," said Rita Stacey, curator of marine mammals for the Chicago Zoological Society. The data-gathering phase of the project wrapped up in February. The investigators anticipate the data analysis to be finished in late June, and the findings will be published early next year.

Brookfield Zoo hopes to continue monitoring its dolphins with the MTag device as it strives to improve the welfare of all of the animals in the zoo's care.

"Welfare will always be a key component in sustaining populations, and that's one of our big pushes. How do you sustain a population under professional care long-term?" Zeigler said. "Once we complete a study, we don't sit back and go, 'OK, we're done.' We continue. Welfare is never shut off here; it doesn't end when the animal care staff goes home. It is around the clock."

The cetacean project was partially funded by a $740,000 national leadership grant from the Institute of Museum and Library Services. Some of the participating facilities also donated to the project.

Along with the published papers, an app called ZooPhysioTrak is being developed with the health indicator reference ranges so that professionals, including veterinarians, can use the data in their own work to monitor the welfare of cetaceans.

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Zoo veterinarians, behind the scenes and in the field (July 15, 2017)

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Brookfield Zoo invests in imaging with full-time radiologist (July 15, 2017)

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