How do you re-home a rhino by helicopter? Upside down

Moving endangered rhinos to new areas is a vital part of their conservation. War-torn helicopters from the Vietnam war are airlifting the creatures to safety.

Zipping through the skies over South Africa, a 1,300kg (2,865lbs) horned herbivore is dangling by its feet from a helicopter. It may be a shocking sight to behold but, within the last decade, the use of helicopters in rhinoceros conservation has been gaining momentum in South Africa, Namibia and Botswana. 

Black rhinos are critically endangered, according to the International Union for Conservation of Nature (IUCN). However, thanks to conservation efforts, their numbers are on the rise. Today, black rhinos have a population of roughly 6,500 – up from the 1990s' low point of less than 2,500, when poaching and habitat loss drove the species to the edge of extinction.

Black rhinos are moved around for three reasons, says Ursina Rusch, population manager for the WWF South Africa Black Rhino Range Expansion Project. First, to protect them from poaching. Secondly, for monitoring purposes – rhino researchers often take the opportunity to insert satellite GPS telemetry into the rhinos' horns. And, thirdly, to ensure their genetic population is as diverse as possible. The species mostly exists within protected pockets on public and private reserves, so translocation is one of the only available methods to increase their range.

"If we don't translocate rhinos and create new populations, they will inbreed enough that they crash, or run out of resources and stop breeding," says Rusch. Black rhino population growth rates are density dependent. This means if a rhino community is too crowded, the females will start having longer intercalving periods – the time between the birth of one calf and the next – and so produce fewer calves, an evolutionary response and adaptation to resource management.

While the transport of animals for population regrowth and genetic diversity isn't new, the regular use of helicopters in this fight is. Beginning in the 1990s but refining methods since the 2010s, helicopters have "revolutionised the world of rhino conservation", says Rusch. Her WWF project has translocated around 270 rhinos, of which about 160 have been airlifted. 

Leaning from an airborne helicopter, a veterinarian "darts the rhino in the bum" with immobilising drugs, typically targeting youngsters or dominant bulls that need to be removed to prevent inbreeding, says Rusch. Rhino immobilisation typically involves a potent opioid and a tranquilliser.

Whereas before veterinarians would have spent 20 minutes on-foot tracking a half-way-sedated rhino, the helicopter team now saves precious time by aerially tracking the rhino – and within four minutes, the rhino falls unconscious, says Rusch. By the time the rhino goes down, the ground team and the helicopter team spring into action: quickly approaching the rhino for processing. They take biological samples and measurements and insert microchips for monitoring.

Next, the crew ties big, soft straps around the rhino's four ankles. The straps connect to a single rope which is hooked to the underside of the helicopter.

Then the move happens. The helicopter airlifts the rhino, which dangles below, to a central location – generally an open field – where ground crews are waiting, says Rusch.

Historically, the rhino would have been woken up from the immobilising drug and walked into a crate, before being hoisted onto the back of a truck headed for a conservancy. But these road trips could be stressful for the rhino passengers; they're awake for the journey (albeit, sometimes, anaesthetised) and standing in a crate, which can cause muscle or horn damage – or even occlude their airways, which can be fatal. Moreover, the limited road network in the region and difficult terrain made it hard to reach the remote final locations using ground transport. 

This is where airlifting comes in. The health risks of crate travel and lack of roads – for instance, in Namibia's Kunene region – mean that nowadays, helicopters are increasingly used for the translocation of rhinos, explains Robin Radcliffe, associate professor of wildlife and conservation medicine at Cornell University, in Ithaca, New York. Conservationists "really only consider slinging" as a solution when the capture or release site is inaccessible by road, he says, or when slinging significantly cuts down on transport time.

In Rusch's experience, researchers and conservationists employ two main helicopters to transport black rhinos: the Airbus AS350 Astar and the UH1-H Huey.

The Airbus AS350 Astar, nicknamed the "Squirrel," has been used since 2021, says Rusch. This helicopter is small, cost-effective and readily available in South Africa, she adds.

UH1-H Hueys, on the other hand, are designed for lifting large loads. Famously used during the Vietnam War, some of these "iconic helicopters" still exhibit bullet hole patches and floor installations for mounted gun covers, says Rusch. Nowadays, these military-grade helicopters – complete with windows under the cockpit so the pilot can see the ground below  – are valuable for civilians in firefighting and rhino conservation. 

"The Hueys' blades have a unique flap – they really slap the air," Rusch says. "That was the sound soldiers in the Vietnam war wanted to hear, feeling that relief of someone rescuing them." The Huey – made famous by Hollywood films including Apocalypse Now, Platoon and Full Metal Jacket – has become synonymous with the Vietnam War and provided close heliborne support to US soldiers, evacuating the wounded and the dead.

The fateful twist of using a machine of war to save lives is not lost on the conservationists who fly in the helicopters. "Ironically, in the 80s, helicopters were used by some poachers to kill rhinos," says Radcliffe. "The fact that helicopters are now being used to save them is a wonderful example of conservation." Translocation is one of the most valuable tools of rhino conservation, he adds.

WWF's Black Rhino Range Expansion Project has 18 project sites, with over 400 black rhinos spread across the site, making up 15% of all black rhinos in South Africa, says Rusch. "Really none of this would be possible without helicopters, both in terms of darting and transferring rhinos out of inaccessible areas," she says. 

Radcliffe's team, which partnered with Namibia's government, pioneered the netless, slinging method of moving rhinos upside down under a helicopter. In 2021, Radcliffe and his colleagues won an Ig Nobel Prize – an award satirising the Nobel Prize given to "research that makes people laugh and then think" – for their work on hanging black rhino upside down.

As the opioid used reduces the rhinos' blood oxygen levels, it's all the more crucial to determine which flight position is best for breathing. Before settling on the upside-down position, Radcliffe and his fellow researchers tried laying the flying rhinos on boards tethered to the helicopter, which wasn't aerodynamic as the board caused excess swaying in mid-air, says Radcliffe.

Then, his team tested rhinos in nets, which "aerodynamically worked a bit better, but still wasn't ideal". The net's positioning compromised the rhino's breathing. Plus, the net's metal frame added considerable weight and required even more ground personnel to place the rhinos into the net, "which defeated the purpose of having a quick and efficient transport method", explained Radcliffe.

Airborne inversion is the safest option, says Radcliffe. The anatomy of the rhino means it is, remarkably, able to breathe comfortably upside down, Radcliffe says. Hanging by their legs, the weight and build of rhinos allow them to extend their head and neck downwards, straightening the spine. Also, a "safer, smoother flight" occurs because the rhino horn acts as a "tail feather or wind vane," reducing the risk of spinning. "The great thing about lifting the rhinos upside down by their feet is that they're aerodynamic themselves," says Radcliffe.

While the image of an upside-down rhino may initially seem "cruel", the rhino's well-being is always "paramount" before, during and after the 10-30 minutes of airborne time, says Rusch. "The rhino is constantly under supervision of experienced veterinarians and pilots, who can tell if the rhino is comfortable or straining," she says.

Nonetheless, conservation is not without some cost. Helicopter-use creates air and noise pollution. "In a perfect world we'd have a zero-carbon footprint," says Radcliffe. "But we, as humans, are obligated to make a concerted effort to save species like the rhinoceros. They are in serious decline, not because of normal ecological processes, but because of our own actions."

Rhinos have existed for 50 million years and fossil evidence indicates that there were once upwards of 150 rhino species. Now there are five.

"I don't want to tell my grandchildren that we did have rhinos when I was growing up, but they're no longer here because humans poached them and destroyed their habitat," says Radcliffe.

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Slowly but surely, helicopters are making a difference. Thirty years ago, the black rhino population in Kunene, in the north-west of Namibia, was depleted, explains Radcliffe. However, in 2010, Namibia's first rhino airlift has allowed these animals to return to the region. Due to the impassable, vast mountain ranges in the region, the airlift allowed the introduction of rhinos into areas that otherwise would have been beyond reach. Scientists, like Radcliffe, are committed to continually studying and honing these heli-moves, and they plan to incorporate emerging technologies such as drones and satellites into rhino conservation too.

Radcliffe envisions that in the future, this innovative method of rhino conservation could even be applied to the rainforest environments of Indonesia, where Sumatran rhinos are critically endangered. And beyond rhino, the technique of lifting large ungulates – or large mammals with hooves – upside down has also been applied to other species such as elephants and some endangered antelope, Radcliffe adds.

In the meantime, according to Rusch, South Africa's translocated rhinos seem to be thriving – grazing and breeding in their new homes.

"You get to know the rhinos, their individualities, their personalities," says Rusch. "They get released on the other side, and then you get to watch these populations grow – from first to second to third-generation offspring."

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