| 1 | Old school VHF trackers |
Today, there’s two main types of tracking which biologists use for bear collars – VHF and GPS. VHF stands for Very High Frequency and is also known as “radio tracking”. It’s a much older system than GPS, and when it first appeared in the 1960s, it revolutionised tracking technology. By 1979, one company claimed to have sold 17,900 VHF units. It was quickly employed for lions and sub-Saharan elephants alike, but one of the first test subjects in the 1960s was the grizzly bears of Yellowstone Park.
To reveal the bear’s position, these collars emit a pulsed radio signal which scientists pick up using a receiver, which can either be a static machine or a handheld radio, equipped with a directional or “bendy” antenna. The machine isn’t too dissimilar to a home radio. Sometimes, the term “telemetry” is used interchangeably with VHF, but telemetry refers to the actual process of data transmission by radio shortwaves. The radio tracking of bears involves telemetry, but radio tracking is the name of the overall operation. Sometimes, these collars are referred to as pulse collars.
The technology for VHF has advanced a long way over the years. Originally, the battery life was miniscule, but these days, it’s a full 3 years, thanks to advanced microprocessors which keep the collar on minimal power when not transmitting. The difference to GPS is that a VHF collar only transmits twice per week, making it less accurate, but more energy efficient.
| 2 | Secrets of the VHF trade |
With VHF tracking, it’s never as simple as slipping a collar on and waving one last goodbye to your animal friend. There’s complications with each animal, like polar bears, for example, who gain and lose so much weight every year that the VHF collar inevitably slips off. Grizzly bear necks don’t change much compared to polar bears, but instead, the problem is their brutal fighting style: their love of swiping at each other’s necks.
Consequently, manufacturers have gradually made VHF collars sturdier over the years. They’re now made from leather, braided nylon, or the synthetic materials of unbreakable dog collars, complimented by adjustable bolts and buckles.
The all-important battery is normally encapsulated in epoxy or resin, and the antenna is positioned between the two toughest layers of collar material, to prevent the bear from breaking it, usually while scratching its neck on a nearby tree stump. If the collar does have an external antenna, then it’s always located on the exact back of the bear’s neck.
The manufacturers also choose the materials carefully, to protect the antenna and batteries from the environment. A wild bear’s daily activities involving swimming through rivers, camping out in rainstorms, and enduring bitter cold. Then there’s the wide variety of add-ons. Some VHF collars have a pulse rate monitor, using similar technology to smartphones. This too can shut down during inactivity to save battery power, and only restart when a sensor detects that the bear is moving again.
| 3 | Technical difficulties |
All this is useless without actually acquiring the bear’s data, and with VHF radio tracking, there’s several methods of download. There’s the standard wait and receive method, but advanced VHF collars also have a “store on board” feature where information on the bear’s movements gradually accumulates inside the collar’s onboard microchip. When bear researchers get close enough for a signal, they can then download all the data at once.
Another option is to wait until the bear shakes its collar off, retrieve it, and then collect the data manually. Standing in the correct position is vital with VHF radios, as standing at higher altitudes massively improves the transmission. You also have to angle the antenna correctly, pointing diagonally towards the bear’s location – but that requires knowing where the bear is in the first place.
Park rangers in Yellowstone or Sweden require detailed training for all of this. To find the bear, on foot researchers use the “homing system”, where they pick up the transmission, before following the direction through the wilderness as the signal gradually gets stronger, and stopping abruptly once the bear is finally in sight. The other method is triangulation, where a researcher receives 3 signals, which he triangulates to calculate a rough location for the pursued bear. This is normally accurate to within 200 metres, but sometimes, biologists are forced to use only 2 bearings. The further away the bear, the larger the possible error – being within a few kilometres is a must.
| 4 | Technology is advancing |
As the years go on, VHF collars are becoming smaller and smaller. Just like computers or mobile phones, the technology inside the casing is shrinking to magnifying glass proportions. Originally, VHF collars could only be used on huge animals like bears, but now, they’re suitable for endangered ducks and birds. Some VHF collars are even implanted beneath the skin.
One of the coolest innovations is an anti-snare VHF collar. This is equipped with studded metal plates, so that if a bear or lion makes an unwise choice and sneaks under a jagged metal fence, there’s a massively increased chance of the barbed wires getting snagged on the bear’s collar and not its neck, saving it from the dreaded noose effect.
With the VHF collar relying on radio reception, it was only a matter of time before local bear enthusiasts cottoned on. And cotton on they did, as in 2016, Alberta and British Columbia reported a spate of people bringing telemetry receivers into the wilderness, to have a real life teddy bear encounter. This wasn’t what the scientists had in mind! The hikers acted all innocent, but these weren’t ordinary radios or walkie talkies – they were equipped with special high frequencies. Angry rangers argued that there was no logical reason for hikers to be carrying them. A $25,000 fine was imposed in Kooteney, Yoho and Banff national parks for carrying a telemetry receiver, under the crime of “wildlife harassment”.
| 5 | Satellite tracking |
The inbetween system, meanwhile, is the oft-forgotten satellite tracking. This is similar to VHF tracking in that the collar emits a signal containing the data, but instead of a world-weary conservationist travelling on foot with a receiver, this data transmits via a satellite. If a bear is fishing for salmon by the Brooks River of Alaska, then Dr Scienceborg will know about it from the comfort of his desk.
Each bear collar contains a platform transmitter terminal (PTT), which broadcasts a location every 90 seconds. This requires a powerful battery, which lasts for 3-12 months, or longer if scientists put it on a low power mode. A space-dwelling satellite orbits in the range of this collar roughly 8-12 minutes every day.
The flaw is that satellite tracking is less accurate than both VHF and GPS. One study found an average error in the estimated location of 480 meters. 90% were below 900 metres in error, but some were several kilometres away. At $3000-$4000 per PTT, satellite tracking is ten times more expensive than the average VHF collar, but without much added accuracy.
Satellite collars kicked off in the 1970s, and bear and elk were the first creatures to be tracked, but these days, it’s rarely used on bears – it’s more the domain of sea-based animals like loggerhead turtles, which are very difficult for scientists to get close to.
| 6 | The rise of GPS collars |
Although effective, the big flaw with VHS collars is that close proximity is a must, i.e. a scientist in the field or a plane flying overhead for several hours, searching in vain. If the scientists are in cars, then all they can do is drive down nearby roads in desperate hope of picking up a signal. They’re also restricted by snowy weather, rainy weather and potentially being mauled by a different bear. And when they do receive the data, there’s no precise location like with GPS collars, just skilled guesswork in a rough vicinity.
VHF collars aren’t exactly extinct as of 2022, but in the bear heartlands of Sweden, for example, only VHF collars were used until 2003, when GPS collars slowly began to replace them. Bear trackers in the Canadian rockies also began the switch to GPS collars in the early 2000s. A shift is happening slowly but surely.
GPS itself started as a US military project back in 1973, and in 1993, the final satellite was launched into space. Though both include high tech outer space machinery, GPS differs to traditional satellite tracking. Instead of a simple location transmission by satellite to the scientists’ offices, the satellites supply the raw locational data themselves by scanning the Earth. This data is stored in the collar for download, or broadcast to ready and waiting scientists. In total, the GPS network has 24 satellites.
| 7 | Barely different to a spy thriller |
With GPS collars, scientists can receive a marauding bear’s coordinates down to the exact meter. It works exactly like the unjustly pursued hero in every modern thriller who forgets to turn his smartphone off and gets tracked by FBI agents. Scientists can also be sent coordinates much more regularly, which they can set at predetermined time intervals, usually every hour.
The basic kit of a GPS collar is a GPS receiver and antenna, a VHF backup, and a battery power supply, and this battery is the first downside of a GPS. Normally, there’s barely any power drainage, but when the collar’s beacon attempts to connect with a satellite, the drainage goes into overdrive. This is why if a bear ventures into a heavily forested region, the GPS collar will die much more rapidly – it can sometimes take 200 minutes to connect with a satellite. This flaw is now spurring the next technological revolution, tracking collars which promise a connection time of only 10 seconds.
The first ever GPS location tracker was sold by Lotek Engineering back in 1994. They’re cheaper now, but at $3000-$4000, your average GPS bear collar is ten times more expensive than a traditional VHF collar. That’s ignoring the extra equipment like the data receiver, the accompanying software, a spare battery for $3500 – the price of tracking one bear can end up at $10,500. But ultimately, GPS collars usually save money compared to VHF, because they massively cut down on operational costs like a ranger’s wages or plane fuel.
| 8 | How biologists retrieve the data |
When tracking brown bears or any wild animal, GPS collars have 3 main methods of data download. The data can either travel back to another satellite and to the scientists, through a long range radio and to the scientists, or it can be collected as store on board (SOB) data once the collar has dropped off. That brings us to another modern day technology – GPS collars with automatic drop offs. The first version unlocks after a set period of time, which the scientists cannot alter, only the manufacturer. After placing the collar on the tranquilised bear, a small magnet must be removed, which activates the countdown, which is commonly three years.
The second version is remote controlled. This time, removing the magnet activates the sensor, rather than the timer. It’s only close range – a scientist must be within 200 metres to press the button and release the collar. To find the bear, you have to use the collar’s VHF backup system.
GPS tracking has even helped to exonerate accused bears after the fact. When a mystery bear chased 209 sheep off a cliff in the Spanish Pyrenees in 2017, local troublemaker Goiat was blamed, but his GPS collar showed the innocent bear to be far away at the time. It also allowed Papillon the escape bear to roam the Italian alps for 9 months, this time because his kidnappers had foolishly delayed applying the collar. To be fair, he was only in custody for an hour before jumping the fence.
| 9 | When the collar can’t contain them |
Never underestimate bears! No matter how technologically advanced a collar is, the smartest, wisest bears will always be capable of removing them. Case in point – Split Lip, the second most dominant bear in the Canadian ski town of Banff (with the most dominant being The Boss). In 2015, Split Lip was one of 13 local bears to be given GPS collars, to see if they visited the berry woods or strayed too close to hikers. Most importantly, over 10 bears have been killed on the railway tracks near Banff since 2000, and scientists were desperate to see why they spent so much time on them. On October 29th 2015, Split Lips’ collar was unusually static, and the local rangers later found it lying alone on Mystic Pass. All signs suggested that Split Lip had removed the collar himself by rubbing his back against a tree. They also found a cannibalised grizzly carcass nearby – maybe Split Lip was ashamed.
Sometimes, the more cumbersome VHF system leads to epic failures. In 1995, bear conservationists in Austria wanted to replace the radio collar of Djuro, a giant Slovenian male bear introduced one year earlier. They waited in the woods for 149 days and 149 nights, before finding that Djuro had shaken the collar off. In October 2015, Italian scientists managed to place a GPS collar on a male bear in Trentino, but because his neck was so thick relative to his head, it slipped off mere hours later.
| 10 | The collaring debate |
It’s not comparable to the debate over farmed meat, but some call the bear collaring process cruel, or fundamentally against the concept of a pure and untouched wild. To collar bears, scientists lay a tube trap, like the tubes of a children’s playpark, with a piece of rotting roadkill inside. A hungry bear crawls inside, before a gate closes behind it and a warning goes out to rangers, who arrive with tranquiliser guns. Then the bear is weighed and measured, but may also have a tooth pulled to check its diet, while its eyes are sprayed to keep them moist.
The process lasts an hour, but some argue that it imposes a lasting trauma on the bear. Some point to figures showing that 16-20% of collared bears cause conflict with humans. Then there’s implanted GPS microchips, used on sub adult bears whose necks are still growing and would inevitably get strangled by a collar. Putting something under the skin horrifies many bear enthusiasts. More fundamentally, some believe in the magic of nature, and that collaring is an attempt by mankind to control everything it touches.
One of the most prevalent worries would be totally incomprehensible to a human from the 19th century – that illegal hunters could hack into a collar’s GPS coordinates to secure their kill! This almost happened in India back in 2013, when hunters tried to access an endangered Bengal tiger’s coordinates. Generally though, there’s no definitive evidence that collaring normal bears turns them into bloodthirsty monsters.
Leave a Reply