From a population of 500,000 in the early 20th century, just 29,000 rhinos remain in the wild today.
The vast majority are located in South Africa, which lost a record 1,215 animals to poachers in 2014, a sharp increase from 668 in 2012.
With well-resourced criminal syndicates determined to harvest the rhinos for their horns, that fetch more than gold, diamonds or cocaine
on the black market, conservationists are under pressure to find solutions before the charismatic creatures disappear forever.
On a private reservation at Kruger National Park, home to most of South Africa's rhinos, rangers are putting their faith in advanced technology to turn the tide.
The 62,000-hectare reserve is surrounded by electrified fences equipped with Wi-Fi enabled sensors that feed information to a control room. The site is covered by surveillance cameras, and the access gates require biometric identification.
"Once someone has gone through the fence we know about it," says Reserve Warden David Powrie "Secondly our rangers know about it....to do the work before the shot is fired and before the rhino dies. That's where the difference comes in -- communication in real time."
The initiative has been led by Bruce Watson, a ranger and property owner at the reserve, and an executive at tech company Dimension Data. Watson leveraged his connections with Cisco Systems to build the unique network.
"The (local) infrastructure is very limited so we have had very little to work with," says Watson. "But what we have created is a tech solution in terms of the internet of things around connected conservation."
The next phase of the project will see the introduction of thermal imaging, seismic sensors around the perimeters of the reserve, and drones patrolling the skies.
The rangers will combine these new capabilities with traditional sniffer dogs and trained soldiers on the ground, as part of a co-ordinated effort to catch and deter poachers.
This approach already appears to be bearing fruit, with almost six months since the last discovery of a dead rhino in the reserve. However the prohibitive cost of $1.5 million per year for the system will keep it out of the reach of less wealthy institutions.
Ultimately, raising awareness could prove more important than technology in the battle to save the rhino, according to leading local conservationist Dave Varty.
"I think that in the source markets that are buying rhino horn - at a higher level -- it's really becoming uncool to be part of that thing," he says. "I think in society in the east there's a change of attitude."
But on the reserve, rangers are leaving nothing to chance.