University of Turku thermal imaging monitors reindeer stress

17 Sep 2024

Non-invasive assessment method could improve studies of animal welfare.

Thermal infrared imaging can be a valuable tool in monitoring animal welfare, allowing subjects to be observed without undue disturbance.

Previous examples have included the 2019 collaboration between IR-imaging specialists Flir, now Teledyne Flir, and the WWF intended to stop illegal wildlife poaching of rhinos across parks and game reserves in Kenya.

A team from Finland's University of Turku and the University of Tours, France, has now investigated the use of thermal imaging to monitor eight reindeer in Finnish Lapland, again using Teledyne Flir technology.

Reported in Animal Behavior and Cognition, the study aimed to validate the use of IR thermal imaging as a non-invasive tool for monitoring stress responses in the reindeer, as an alternative to implanted devices such as heart rate sensors. The goal was to assess whether the technology could improve the assessment of animal welfare.

"Contactless temperature measurement has the potential to assess the emotional state of animals affected by human physical contact," noted the project in its paper.

"Reindeer, being highly sensitive to touch and naturally avoiding physical contact, exemplify this case. With growing interest in safari tours involving sledging reindeer, there is a need to investigate how these animals are affected by human interactions and how they adapt to daily close contact."

The team employed a Teledyne Flir E6-series thermography camera, and for the purposes of the trial took images 50 to 80 centimeters from an animal's head, although the reindeer under observation were accustomed to tourists with cameras and so not thought to be unduly disturbed by the researchers' presence.

IR imaging monitors interactions with humans

The images were used to provide thermal data about one particular spot on the animals, the small area at the inner corner of the eye called the canthus where no hair is present to confuse the readings. This approach has not previously been used on species like reindeer, according to the project.

While under observation the reindeer were petted by an experimenter, one unfamiliar to the animal, to introduce a source of outside stress and observe whether the thermal imaging recorded any change in temperature at the eye canthus.

As the animals exhibited avoidance behaviors during the interaction with the stranger and tried to move away, the infrared thermal camera footage showed a decrease in the temperature of the eye corner of the reindeer. This started when they were petted by the stranger, and was followed by a gradual increase when the stranger stopped petting the animal.

The results could have implications beyond reindeer welfare, providing insights into the welfare assessment of other species subjected to human interactions, according to the project team.

There is now a growing body of literature that emphasizes the need for responsible practices in animal tourism, and the study serves as a reminder of the importance of monitoring animal welfare and adapting practices to enhance the lives of reindeer and other working animals.

"Our findings demonstrate that infrared thermal imaging can effectively capture the physiological stress responses of reindeer during human interactions," commented Océane Liehrmann from the University of Turku. "This technology allows us to monitor the emotional states of reindeer without invasive procedures, which is crucial for their welfare."