New tracking device for better monitoring of wolves

Following the journey of a wolf and the well being of a wild horse has never been easier. With GPS wildlife trackers powered by the animal’s own movements, University of Copenhagen researchers have solved a problem faced by biologists and wildlife managers trying to track wild animals year after year: dead batteries.

The return of the wolves in Europe has preoccupied people across the continent in recent years. Where’s that? What’s the range? What is life? The only way to get a definitive answer to this question is through GPS tracking. In December, it was cause for celebration when GPS collars were put on wolves for the first time in Denmark. Just three months later, the signals stopped.

GPS trackers that stop working or run out of power prematurely are often a problem and a source of frustration among researchers who want to track mammals for longer periods of time, says biologist and postdoctoral fellow Rasmus W. Havmøller of the University of Copenhagen. Usually, the battery is the problem:

“When studying wildlife with GPS technology, the biggest limitation is the battery. This is very frustrating. It’s not uncommon for someone to be able to track an animal for months at most before a GPS device turns off. But tracking animals for longer periods of time is often important, as is the case with wolves in Denmark. Therefore, we need a more reliable power source,” said Rasmus W. Havmøller and continued:

“Solar cells work well for birds, but they are so fragile that mammals tend to destroy them. In addition, many mammals are nocturnal. So we need to find an alternative. I have long thought about the intelligence of the automatic watches that most of us wear, which collect energy from our own body movements.”

Together with research colleagues at UCPH, the Max Planck Institute of Animal Behavior and DTU, Havmøller developed a battery-free GPS wildlife tracker that uses kinetic energy – that is, energy generated when an animal moves. A scientific article about the research has been published in the journal PLOS ONE.

Lasts a lifetime, at a tenth the cost

“It really works! The more an animal moves, the more energy it generates and the more GPS location messages it sends. Unless the equipment itself breaks, it will work throughout the animal’s life. At the same time, it weighs only 150 grams – significantly lighter than most other GPS trackers – so it can even be attached to small mammals,” says Havmøller, adding that the device costs less than a tenth of a traditional GPS collar, which operates on the top. up to €3500-4000 each.

Rasmus W. Havmøller and his colleague, lead author Troels Gregersen, assembled the GPS tracker themselves in a small laboratory at the Danish Museum of Natural History.

The device, dubbed “KineFox” by the researchers, has been installed on one of the Danish Nature Agency’s wild horses and has been transmitting data about the horse’s position for the last six months. The tracker has also been tested on dogs and bison. The plan is to carry out long-term trials on several animal species.

Ideal for rebuilding animals

Rewilding is one area where researchers envision GPS trackers making a difference. The lack of supervision of animals released into the wild has become a problem that has generated intense debate in recent years.

“Systematic human control of wild horses and livestock, to prevent them from starving for example, is very resource intensive. Our trackers are up to the task,” says Rasmus W. Havmøller.

Because the tracking unit contains an accelerometer that measures the movement of the animal, wildlife managers can see at a glance the condition of the animal by its activity patterns.

“Studies with cows and pigs show that they start to move differently when they are sick. In this way, it is likely that trackers can also learn something about the animal’s health. This means you can comply with surveillance laws without having people go out every day to find and examine animals,” said the researcher.

Can help us protect endangered species

Havmøller points out that Kinefox can also help endangered species, where knowledge about how they live and move is lacking:

“There is no good alternative to these GPS devices in terms of serious long-term studies and studies of how animal species spread. Because the equipment is too big, too heavy or too fragile. But it is very important to understand how species move from place to place, and where they are shot or poisoned, for example – at least if we are to protect them better.”

He himself was frustrated by a GPS device whose battery suddenly died while studying the endangered leopard and wild dog:

“There are endangered species that we know very little about what they do for most of their lives. This includes tigers, which can travel thousands of kilometers, as well as the wild dogs and Asian leopards I am involved with. When stray dogs reach sexual maturity, leave their mothers and go off on their own, they are especially vulnerable. But since then, we know nothing about what they did and why some died while others succeeded. This is a black box. I hope this discovery can improve it,” concludes Rasmus W. Havmøller.

Havmøller and his research colleagues are now in contact with several potential stakeholders about long-term testing of Kinefox in various animal species.

FACT BOX: HOW “KINEFOX” WORKS.

• Instead of a battery, “Kinefox” has a so-called capacitor, which stores the energy that the device harvests through animal movements.
• Data from Kinefox is transmitted via Sigfox, a wireless network widely distributed around the world.
• Whereas traditional GPS wildlife trackers usually cost € 3,500-4,000, new transmitters cost around € 270 in material form.
• Researchers have chosen to use an open source design for Kinefox, making the information available to everyone.

FACT BOX: ABOUT THE RESEARCH

• The researchers behind “Kinefox” are Troels Gregersen, Peter Rask Møller, Linnea Worsøe Havmøller and Rasmus Worsøe Havmøller of the University of Copenhagen’s Danish Museum of Natural History; Timm A. Wild and Martin Wikelski of the Max Planck Institute of Animal Behavior, Germany; and Torben Anker Lenau from DTU Engineering Design and Product Development.
• Scientific research articles have been published in journals PLOS ONE.
• This research project is funded by the Villum Foundation under the Villum Experiment program.