By Victoria Gill
Science and nature reporter, BBC News
The device is implanted in the inert part of the rhino's horn
Five rhinos in South Africa's North West province have been fitted with a Global Positioning System (GPS) device to help protect them from poachers.
The GPS chip is fitted into the rhino's horn by drilling a small hole in the inert or dead part of the horn.
As well as GPS tracking, the device is equipped with alarm systems to alert game wardens of unusual movement or if a rhino is outside of the park.
The North West Park Board is testing the devices in Mafikeng Game Reserve.
The board began this novel project in April of this year, when they tested the chips.
Park vets carried out the first implants the system is now "up and running" - constantly monitoring the five animals.
"It's basically a satellite system which connects with the cell phone system and we can monitor the animals on whatever time delay we want," Rusty Hustler, head of security for North West Parks Board, told BBC News.
"There are a number of alarms that can be programmed: one for excessive movement, so if the rhino starts running, and another that goes off if the rhino sleeps for longer than six hours, which is abnormal."
An alarm also sounds if the chip goes outside of the area of the game reserve.
A reaction team in the park would be able to track and quickly reach the animal if an alarm went off.
More than 200 rhinos had been slaughtered in South Africa since the start of the year and there is a high demand for rhino horn, a prized ingredient in traditional Chinese medicine.
Mr Hustler said that the board was looking to use the devices in animals in other North West province parks and were planning to tag more animals in the coming weeks.
He added that in the future, the devices could even help to track rhino horns that were taken by poachers to help combat the illegal trade.