Monday, January 30, 2012

Taking the temperature of elephants

Many of our readers will be familiar with the principle of operation of thermal imaging (infrared) cameras and how they can be used in a variety of applications ranging from determining the thermal loss of buildings, detecting specific gases, or monitoring production processes.

But like me, most people might be surprised to hear that a group of researchers from the University of Guelph (Ontario, Canada) are now using such cameras to study the thermoregulation of animals such as elephants.

That's right. As a member in the Department of Animal and Poultry Science (APS), Esther Finegan and her students have filmed elephants in Busch Gardens zoological park in Florida with a thermal imaging camera to see how and when they store and radiate heat. She and her students are now pioneering similar thermoregulation studies at the Toronto Zoo.

While the use of thermal imaging will undoubtedly prove to be an invaluable tool that will enable zookeepers and landscape architects to better design the animals' surroundings to keep them happy and healthy, this isn't the only means by which researchers have measured the temperature of such beasts.

Last year, for example, scientists at the Research Institute of Wildlife Ecology (FIWI) at the University of Veterinary Medicine (Vienna, Austria) showed that Asian elephants respond to high daytime temperatures by significantly lowering their body temperature during the cooler night hours. By doing so they create a thermal reserve that allows them to store heat and so prevent heat stress as temperatures rise during the day.

To reach that conclusion, they fed small telemeters to a group of captive elephants in Thailand and a group at the Munich Zoo Hellabrunn to monitor temperatures in the animals' gastrointestinal tract. The telemetry system, which permits the continuous recording of temperature, had previously been developed at the Research Institute of Wildlife Ecology.

Statistical analysis of the data confirmed that while the overall mean body temperature was similar in both the Thai and the German elephants, fluctuations in body temperature were on average twice as large in the Thai animals as in the German ones. The Thai animals had both a higher daily peak temperature and a lower minimum temperature, which the scientists related to the higher mean ambient temperatures in Thailand.

In fact, the body temperature of the Thai elephants dropped at night to well below the normal average, meaning that Thai elephants start the day with a much larger thermal reserve than their German counterparts.

It just goes to show that, just as there's more than one way to skin a cat, there is also more than one way to take the temperature of an elephant. But if I were an elephant, I'd probably prefer the noninvasive image-processing approach rather than ingesting a telemetry system.

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