Toll tag technology is repurposed for use in wildlife monitoring
August 31, 2022
By Fábio De Castro | Agência FAPESP – A Brazilian company is developing a new telemetry system that will offer a handy alternative for monitoring wild animals: it is based on a similar technology to the windscreen tag used by drivers to pay road tolls and parking fees remotely.
The new system is being developed by Trapa-Câmera, a São Paulo-based startup, with support from FAPESP’s Innovative Research in Small Business Program (PIPE). The firm wants the technology to be used by biologists in scientific research, and by environmental consultants and non-governmental organizations (NGOs) to monitor endangered species.
Wildlife radiotelemetry – the transmission of radio signals from a device attached to an animal – is widely used by biologists and ecologists, especially in the management of conservation areas and in studies of animal behavior. However, the battery that powers the transmitter may become a problem, depending on the study design and target species.
The absence of a battery is precisely the main difference between conventional telemetry devices and the new tool developed by Trapa, which does not use radio transmitters, explained biologist Sergio Marques de Souza, the researcher responsible for the project and an equity partner in the firm.
“One of the problems with batteries is weight. They’re heavy enough to be uncomfortable for the animal and may alter its behavior, impairing the research and its results,” Souza said.
Durability is another problem with batteries. “When the battery runs down, you have to locate the animal to swap it out, which entails more stress for the animal. To extend durability, you have to increase the size of the battery and hence its weight. In addition, batteries can leak, releasing substances that are toxic to the animal and to the environment,” he said.
To eliminate the battery, Trapa’s researchers were inspired by the RFID technology familiar from toll payment collection systems. “Instead of a radio transmitter, we use a small label like the RFID tag you put on your car windscreen. This opens up the monitoring possibilities because it can do telemetry for very small animals and even bees,” Souza said.
“The electricity is stored solely in the receivers, which are arranged in accordance with criteria defined by the researchers. When an animal approaches a receiver, the transmitter on the animal is activated and transmits a signal to show it’s there.”
According to Marco Antonio Marques de Souza, Sergio’s father and also a partner in the firm, unlike conventional radiotelemetry systems, which work over large distances, the new device will be used only over short distances of 10-20 meters, so that the receivers can read the tag on the animal. The system is therefore not designed to replace conventional methods under all circumstances, but to offer an alternative in specific cases.
“The battery corresponds to about 80% of the weight of the tracking collars in widespread use, which have the advantage of transmitting data over large distances of up to 2 kilometers. Our label is only efficient over a few meters but weighs less than 1 gram and is made of totally inert material, so it doesn’t adversely change the animal’s behavior. Another advantage is that it can be used for lifelong monitoring of animals,” said Marco Souza, who has a background in computing.
According to Sergio Souza, despite the limited range, the new system will help scientists design studies that could not be done with conventional technology. “Our system will be very useful in several situations, such as studies of linear habitats, which occur frequently in areas of Atlantic Rainforest. When the focus is on corridors connecting forest fragments, our receivers can be placed in them to find out how animals use such corridors, for example,” he said.
Other examples include studies of how animals use canopy bridges and other road-crossing structures, birds in nests and fish in streams, or animals that live in burrows. “The system can be used to monitor bats, for example, by placing receivers at the entrance to their caves,” Marco Souza said.
It will also be feasible to cover an entire area for studies of animals with small home ranges. “This could be very useful for post-release monitoring, for example, enabling researchers to identify the area an animal chooses as its home range with precision,” Souza said.
Low cost and large market
The firm’s researchers believe RFID technology will open up a market not available to conventional radiotelemetry technology. “The battery eventually dies, and so it’s not possible to monitor an area permanently. The new methodology permits this, and to enhance it we propose to reduce the size of the receiver as well. It can be powered by solar energy,” Marco Souza said.
According to him, the new system will also mean lower research costs compared with the cost of projects that use radiotelemetry. Transmitters for large and medium-sized animals, with their batteries and collars or other attachment devices, are not made in Brazil and have to be imported, costing more than BRL 800 when the exchange rate is unfavorable.
“The new system will cost between BRL 0.10 and BRL 0.20 per tag, so research costs will fall by a great deal, especially if we succeed in lowering the cost of the reader,” he said. “Transmitters are very cheap. The upshot is that it will be affordable to monitor many more animals.”
Despite the firm’s innovative application of the technology, the new product cannot be patented according to Brazilian law. However, the tool can be protected as a utility model. “There are two kinds of IP protection. One is the invention patent. The inventor of RFID can patent the product as an invention, for example. The other is the utility model, which is applicable to our case because the system is entirely novel, with a waterproof reader that’s small, cheap and solar-powered,” he said.
Wildlife telemetry collars
Founded in 2004, Trapa makes and markets electronic equipment for wildlife conservation. According to Marco Souza, the firm currently has two product lines for animal monitoring – camera traps and radio tracking collars. “We’ve made camera traps since 2004. More than 3,500 are in use across Brazil. We also provide maintenance for these devices,” he said.
The tracking collar has an innovation in its transmitter, which Trapa developed between 2006 and 2010, also with support from PIPE-FAPESP. According to Marco Souza, conventional transmitters emit a single acoustic signal, whereas different radio frequencies are needed to monitor different animals. Researchers have to decide which animal they want to track before going into the field so that they can tune into the right frequency and station, but a nearby animal with its own collar will not be detected, he explained.
“FAPESP’s support enabled us to develop a system in which all transmitters on all monitored animals transmit signals at the same frequency, each with a different code. With an omnidirectional antenna, a researcher can locate all of them and choose which one to track. This makes fieldwork much more straightforward,” he said.
According to Souza, on principle, Trapa supplies equipment solely to researchers and organizations with scientific aims relating to wildlife conservation and environmental protection. The same will apply to the new technology the firm is developing, which Souza calls a “toll tag” for animals.
“We offer our equipment to scientists at research institutions, NGOs and environmental consultants, but never to hunters, for example,” Souza said.
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