Saving rhinos from extinction sometimes requires moving them to safety. To do this, Namibia relies on helicopter transport. The technique is obviously not without danger for the animal, but a study has just confirmed that it remains the best option.
Save the rhinos by the feet
In Namibia, home to around a third of 5,500 last black rhinos around the world, sometimes animals have to be moved. This allows to encourage genetic diversity or to place them in national parks where they can be protected from poachers. Some may also be found in one of the country’s conservancies. In these reserves, the inhabitants undertake to protect nature there in exchange for the economic benefits linked to tourism.
Moving a rhino is no small feat, however. Indeed, these animals are huge and Namibia is a very rugged country, displaying several extreme and difficult to access environments. And while some vehicles could reach these rhinos, a walk of several hours in such a landscape could be traumatic.
This is the reason why more and more of these animals have been moved by helicopter in recent years. The operations proceed as follows: a first dart injects them with a powerful analgesic (etorphine and azaperone). In a few minutes, the veterinarians take samples to assess the subject’s state of health, then they inject a dose of morphine to make him sleep soundly. Everything then happens very quickly.
The animal is tied up by the legs before being lifted by helicopter to be transported in half an hour to its new home. During the journey, the animals have a blindfold and earplugs in order to limit the stimuli. But is it all that safe for rhinos?
To find out, a team from the Cornell Conservation Medicine Program visited Waterburg National Park in 2015. “There is a risk every time you move a rhino“, Explains Robin Radcliffe, program director and specialist in zoological medicine. “And we know that when anesthesia is involved, positioning is very important whether you are a dog, a person or a rhino.“.
Initially, Radcliffe and his team speculated that being upside down would compress the animal’s chest and lungs, exacerbating the effects of the drugs. Conversely, they believed that transporting the animal on a stretcher, lying on its side, would be less dangerous for the animals despite the difficult maneuvers for the relocation team.
To test its hypothesis, the team worked with a dozen sedated rhinos. In random order, each of them was placed on its side and then hung from a crane for ten minutes. Meanwhile, veterinarians collected data on the cardiovascular and respiratory functions of the animals in each position.
Their work, recently published, were ultimately surprising. “The physiological effects were about the sameRadcliffe explained. “In both positions, the animals developed hypoxia, a lack of oxygen reaching the tissues. On the other hand, the oxygen levels and ventilation readings were higher when animals were upside down“.
An essential option
Radcliffe and his colleagues suspect that the size and stature of rhinos could be the cause of this phenomenon. Unlike a smaller and softer mammal, the very rigid body of a rhinoceros allows for maintain integrity even in this position. Such a maneuver could also allow the release of the rib cage, thus promoting ventilation and oxygenation of their body.
For conservation teams in Namibia, this study brings greater peace of mind. Being able to safely and successfully transport rhinos by helicopter therefore remains a valuable tool for the conservation of this emblematic species, whose numbers were decimated during the second half of the last century. Over the past two decades, the species has indeed rebounded slightly, but it remains critically endangered.