Different VHF radio collars used within the Okonjima Nature Reserve.
One of the most distinct features the carnivores that live on Okonjima share - is that radio-collar each rehabilitated or researched predator wears.
It is the one feature that creates the most 'talk' – controversial at times - between keen photographers, operators and the guests staying at Okonjima that have come a long way to experience the AfriCat rehabilitation project. It is the one 'sighting' that puts us apart from most other game reserves.
As we all know - Okonjima is home to AfriCat. AFRICAT and the OKONJIMA NATURE RESERVE are dedicated to carnivore research and the rehabilitation of captive predators. Visitors come to Okonjima to learn about the work AfriCat is doing. They come to see a 'working project', and if well informed, understand why most of our cats are collared!
The collars we use today have come a long way from the older, and clumsier looking collars. The old ones use to have massive battery packs which enabled them to last up to 3 years before they needed replacement. They had wide leather bands which gave them durability and also long antennas to give them better range – a photographer’s nightmare!
Today you get the same performance from a collar that is a third of the size of the collars we used 10 years ago. Technology has allowed for a much smaller, lighter and more pleasant looking and feeling collar. This feature has been welcomed by so many tourists as well as those of us researching these carnivores and I am sure the predator as well, for wearing this heavy collar must be uncomfortable and irritating at times, especially during hot, summer days or while pulling down prey.
As the performance of battery life increased, the size of the battery became smaller and so in turn the battery pack, - which is the most distinct feature on the collar - became smaller. The direction technology is taking looks to be towards making battery packs smaller and smaller.
Today you get collars that have no external antennas and very small lithium battery packs.
The good thing is that they are not that obvious on the animal and seem to be more reliable in the long run. They are more lightweight and on average only weigh about 150g.
Now, if you take the average weight of a cat at 35kg, that collar weighs less than 0.5% of the animal. The other good thing is the battery will last more than 5 years on average, so the chances are that the battery will outlast the leather the collar is made of. The other positive point is that the carnivore will most probably only have to be collard twice in its lifetime, which saves them from the stress of having to be constantly darted to change the collar.
The downside is the fact that the range is only about 1.5km to 2km on average. If the vegetation is thick, this range goes down to below 1km, which means if you work with animals that cover huge distances in a day, finding them can be very difficult. Animals that are very territorial and stay in the same fairly small area - are more easily found, but predators like the wild dog and the cheetah that are always on the move, can become quite a challenge to find in 160 sq/km.
These are the collars that most of the Okonjima leopards as well as some of the AfriCat cheetahs are wearing, which has made photographing these researched cats - a more pleasant experience.
The other type of collar we use is larger and has a very visible, external antenna. The good thing about this is the range it gives you when tracking in very thick vegetation. On average the distance you pick up the collar’s signal will stay around 4km on average. Although the collar might look bigger - the weight is not that much more than the smaller collar. Thus if you work with animals that are monitored solely for research purposes - the one with the external antenna is a better option.
Note the external antenna as well as the bigger battery pack, but which does give you better range.
The third collar is the more technologically advanced, GPRS collars. These collars will be placed on animals that are leaving our reserve and going to areas that are not easily accessible by vehicle or foot. These collars not only just send out a VHF signal, but also collect data in the form of GPS coordinates, as well as other technical data on temperature and movement. The other great characteristic of this type of collar is the fact that you can draw up 'alert boundaries' with GPS coordinates, which means - if the animal moves beyond these boundaries you will be alerted immediately via sms to a specified cell phone number of your choice. Other than that you will receive a sms with GPS coordinates for the day - every day, or less frequently if so requested. All the data the collar collects are saved on the collar and then downloaded to a website which you can then download to a computer on a daily basis. This will make very accurate data on movements of cats when relocated to a new area, but will also enable us to keep an eye on problem animals that have been relocated.
The only down side is that you have to release the predator in an area with cell phone coverage, or at least coverage in some part of the area the animal will be moving in. The collar can store up to 250 points in its memory, but then will have to come into cell phone coverage to download the data.
Collars becoming that small that most photographers do not notice them, will most probably not be an option in the near future, for in the end the general design of all VHF collars will stay the same. They still have to be strong enough to survive the daily onslaught that is part of the normal life of the animal being researched.
They will never be able to make the actual leather band, much thinner or narrower than what we have now as the chances are the animal will break it and the collar will not last the daily assault these collars have to endure. The only way to go, is to make the battery smaller and smaller and the transponder stronger and stronger. At the rate technology is developing at the moment, we are pretty sure we will see smaller and smaller versions of these collars in the near future. Some companies are already looking at certain kinetic energy sources to replace large power storing batteries.
THE COST OF RADIO COLLARS:
Another point to take into consideration about the collars – is the financial burden. The normal VHF collars we use at AfriCat costs about N$2 500.00 per collar and are the more popular collars used by most researchers. The GPRS collars however are N$23,000.00 a piece! The decision on which cats get these collars becomes a very difficult one. If you only buy 10 collars, it will cost you close to a quarter of a million Namibian dollars which is a big investment for any non-profit organisation.
Let us hope technology will surprise us in the future, but at the moment we will stick to what works the best for our situation, what we can afford and what is the least stressful procedure for the researched animal.
Using 'internal transmitters' that are completely "tourist friendly" and preferred by photographers – and that are hidden inside the animal – will not be used on Okonjima! This technology is invasive – and is very stressful for the animal who has to carry this transmitter inside, for its tethered to the abdominal wall and there have been reports that it has come loose, which could kill the animal . . . . . and because of its weight can tear out during a hunt or fight, and most probably cause cancer over a period of time.
Tourists have to start understanding that when an animal is seen wearing a radio-collar – it’s a positive sighting. It means research is being conducted and more information about that specie or that animal 'in a certain environment' will be available in the near future. They should welcome the efforts made to come up with regular and new and constant information, instead of complaining that they did not get an opportunity to photograph it without a collar. There still is so much to learn about the animal species all around the world, and 'responsible' radio-collaring will help us understand their behaviour, their needs, their weaknesses and their uniqueness and beauty!
Report by AJ (Andre Rousseau) – Okonjima research co-ordinator
Radio tracking wildlife will always be part of what we do here at Okonjima and AfriCat, and we will always be on the lookout for better VHF technology and always make sure that the animals that have to wear these collars will receive the best suitable collars for that animal.
These pictures show the GPRS collars. The battery pack at the bottom also houses the internal memory bank, and on top it has the GPS receiver as well as the GSM receiver.
The 3 different collars used by AfriCat.