THE stench of rotting flesh hangs heavy over the half-eaten carcass of a rhino, killed by poachers who hacked off its horns and left the rest to the lions. Barricade tape marks out the gruesome discovery in the South African bush: this is a crime scene. Two young women search for bullet fragments and casings with a metal detector, and use a chef’s knife to cut away tissue samples and a toenail. The evidence is bagged and carefully logged in a database. It is grim work but these women, wildlife crime investigators with the South African parks service, are used to it.

Kruger National Park was home to 826 of the 1,175 rhinos killed last year in South Africa. This was a slight dip from 2014, but the number of rhinos killed by poachers increased in neighbouring Namibia and Zimbabwe. Overall, 2015 saw the most rhinos killed since the poaching crisis began nearly a decade ago, fuelled by demand from Vietnam and China, where many people wrongly believe it will cure everything from hangovers to cancer.

Some firms have promoted drones as a sophisticated (and pricey) way to monitor the Kruger park and detect gangs of poachers. “They come with drones promising they will solve everything,” says one park official. But the drones have so far failed to impress the rangers. The Kruger park is huge (about the size of Israel or Wales) and drones have had technical problems with its harsh climate and rugged landscape. Heat-seeking drones, meant to spot poachers hiding in the bush, get confused, because large stones absorb heat during the day and then release it at night. Rangers were being dispatched to hunt rocks.

A low-tech solution still works better. Tracker dogs, working alongside their human handlers, are responsible for more than 70% of arrests of suspected poachers in the Kruger. The powerful nose of a Belgian Malinois called Killer has led to 115 arrests over the past four years. Although the park is continuing to test drones in a project with Denel, South Africa’s state-owned arms manufacturer, the goals now are more modest. “They’re not the game-changer they have been portrayed to be,” says Julian Rademeyer, author of “Killing for Profit”, a book about the illegal rhino-horn trade.

The real problem is that although South Africa tries fairly hard to catch poachers, no one is doing much to tackle the Asian crime syndicates that buy the horns. Unless Asian and African police work together better, the rhino’s future looks grim.