“R” is for Rhinos, and also for …. Radio-telemetry.
The technology known as radio-telemetry enhances our ability to track and monitor rhinos. The principles of radio-telemetry are essentially the same as listening to a radio news broadcast. A small portable transmitter – think of it as a miniature radio station – emits radio waves that travel invisibly through the air, are picked up by an antenna and channeled to a receiver. However, instead of commentary, music or advertisement, the transmitter emits a series of beeps – or is it bleeps? Either way, the sound emitted by each transmitter can be set to a different frequency, allowing the listener to tune in to a specific one and determine from which direction the sound has originated.
Wildlife biologists routinely use radio-telemetry equipment to pinpoint the location of animals that are otherwise difficult to find and track. More often than not, the transmitters are attached to collars that are specially designed not to restrict, hinder or harm but, depending on the target species, sometimes the transmitters can be attached to or imbedded in the animal’s body itself, such as in the dorsal fin of whale or the horn of a rhino. As they say, “This isn’t rocket science,” but developing technologies should allow field researchers to gather more important information about the animals they study.
Two IRF projects employ radio-telemetry as standard practice – monitoring programs for translocated black rhinos in Zimbabwe’s Lowveld conservancies and for reintroduced greater one-horned rhinos in Manas National Park as part of the Indian Rhino Vision 2020 initiative. In Zimbabwe, more use is made of transmitters that can be placed inside a small cavity drilled that’s drilled into the rhino’s horn after it has been immobilized. Black rhinos have two relatively large horns, so the size ratio of horn to transmitter favors this strategy. By comparison, the word “greater” in greater one-horned rhino refers not to the size of the horn, but to the bulk of the beast, and its relatively smaller horn is a less favorable site for a radio transmitter. Consequently, reintroduced rhinos in Assam, India are fitted with special, flexible radio-collars. The science is the same, but there are practical differences to consider. At the end of the battery’s life on a radio-collared rhino, the animal has to be immobilized a second time to remove the collar, which poses some risk to the rhino. A horn implant, by comparison, simply “grows out’’ of the horn after about three years.
By radio-tracking rhinos that are also individually identifiable by sex, size, scars, ear-notches and ear-tags, wildlife biologists are able to continuously monitor their movements across large areas. For example, black rhinos released in Zimbabwe’s Bubye and Save Valley Conservancies can conceivably roam over more than a million acres. On the other hand, greater one-horned rhinos in Manas National Park may tend to concentrate their activity close to the park perimeter and perhaps cross over into unprotected territory. In either case, rhino rangers and park guards must monitor their whereabouts to protect them from the threat of poachers.
A new approach to rhino radio-telemetry is currently being tested in southern Africa – attaching transmitters to ankle bracelets. Although these transmitters are relatively large, they add the capacity to relay positions via satellite links. Some wildlife biologists remain wary of their use, due to the risk of lesions to the rhinos’ legs or because the units can be damaged if the rhinos bash them against rocks or trees. Another new approach is RFID (Radio-Frequency IDentification) transponder technology, which allows smaller devices to be used. This is currently being tested in an International Rhino Foundation project in Zimbabwe, as well as in Namibia.
By experimenting with new ways to track and monitor these impressive creatures, rhino conservationists will gain a better understanding of their ecology and behavior, and hopefully will become more adept at protecting and rebuilding rhino populations.
For more information about Indian Rhino 2020 and the translocation of Greater one-horned rhinos in Assam, please watch the video below.