2023-09-05 23:09:00
Diagnostic imaging, including X-rays, MRIs and CT scans, has long been a crucial tool in monitoring human and animal health. However, for researchers studying wild populations, administering these common tests can be challenging.
In an effort to overcome this hurdle, a collaborative project was launched by scientists from the Woods Hole Oceanographic Institution (WHOI) and colleagues from the Cincinnati Zoo and Botanical Garden, as well as other zoos and aquariums. The team is currently testing the use of thermal video and image analysis to measure heart and respiratory rate in various animals in a controlled environment.
The ultimate goal of this research is to advance the development of non-invasive techniques to assess the health of wild animals, particularly threatened and endangered species for which more invasive diagnostic procedures might carry prohibitive risks.
A new article detailing the work of the team was published today in the journal Biologie BMC. The study highlights the importance of understanding an animal’s metabolic rate or energy expenditure, as this provides crucial information regarding a species’ chances of reproduction and survival.
Unfortunately, collecting these reference measurements from wild populations is logistically complex and often invasive. Even simpler tests, such as obtaining heart and respiratory rates, often require immobilization of the animal, which can present its own risks. Additionally, attaching tracking devices can be both expensive and invasive.
The research, led by MIT-WHOI graduate student Caroline Rzucidlo, investigates the potential of infrared thermography (IRT) combined with Eulerian video magnification (EVM) software to measure the vital rates of exotic wildlife species.
Ultimately, the team wants to apply this technique to study Weddell seal populations in Antarctica, assessing whether these animals will be physiologically primed to survive and reproduce in rapidly changing environments.
“Heart and respiratory rates are often used as indicators to determine metabolic rate,” Rzucidlo explained. “Thermal cameras can detect changes in skin temperature associated with blood flow and changes in air temperature associated with exhalation. So, determining whether thermal cameras might noninvasively capture these temperature changes in animals was the first step.
Even though thermal video cameras can easily measure heat and body temperature, as evidenced by the technology used to detect fever in humans at airports, the question remained whether this approach might be applied to exotic animals. It was not possible to carry out their work directly in the field, because the researchers first had to validate the accuracy and precision of the method, which required controlled adjustment.
“We had no idea how well we might measure temperature fluctuations with the thermal camera, including how far away from the animal we must have been, and how thick the fur, fat or scales would affect the readings,” Rzucidlo explained.
The Cincinnati Zoo and Botanical Garden provided the perfect setting to test various animals under various conditions, allowing researchers to refine their methods. Working with reproductive physiologist Erin Curry and other animal care specialists, Rzucidlo spent months collecting thermal video data on an array of land and sea creatures at the facility.
The study also included work conducted in other locations, such as the Louisville Zoo (Kentucky), the Columbus Zoo and Aquarium (Ohio), and the Salisbury Zoo (Maryland). A total of 58 animals, ranging from Komodo dragons to polar bears, participated in the research.
“Being able to monitor individual animals under human supervision has created a controlled environment to validate this technology that is impossible to replicate in the wild,” Rzucidlo said.
“Zoos provide a unique setting for developing technologies that can contribute to the conservation of wild populations. Animals in zoos undergo regular veterinary checks and some individuals are even trained to voluntarily participate in welfare examinations. Using a stethoscope to get real heart rates while simultaneously collecting infrared video from a variety of species was a very achievable goal,” Curry added.
It soon became clear to the team that thermal video alone was not enough. “Capturing heat and temperature is one step, but we needed the EVM computer software to amplify the temperature changes associated with respiratory rate and heart rate,” Rzucidlo explained. “Using the two together was the winning combination and gave us an unprecedented view of animal health. »
While thermal cameras have already been used to obtain vital rates in a few selected species (mainly hairless ones), this groundbreaking study represents the first application of this technology to a wide range of exotic animals. Additionally, research identifies the specific characteristics that make a species suitable for acquiring thermal imaging measurements.
“This new study takes thermal imaging data in a controlled environment and allows us to establish benchmarks for a suite of species. After developing and refining these methods in the zoological setting, we can then take these imaging techniques and apply them to answer much larger ecological questions in nature,” said WHOI Associate Scientist Michelle Shero.
“We even use this method in Antarctica to study the energetic dynamics of Weddell seal populations. We can use these newly developed methods to begin to ask ourselves how an animal’s energy expenditure might change if environmental conditions change, or what the energy demands are for reproduction.
“Furthermore, the use of non-invasive and rapidly acquired imaging tools will allow us to perform better measurements with less disturbance and for many more animals than would ever have been possible with traditional techniques. That’s what it really takes to start asking questions regarding population health.
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