While hanging rhinos produce spectacularly absurd photographs, behind it lies a severe issue that needs to be addressed. Each year, a selection of apparently weird and pointless scientific experiments receives the Ig Nobel Prize. Awarded by the science humor magazine Annals of Improbable Research, the prize honours projects that “first make people laugh, and then make them think”. A recent study that suspended rhinos upside-down by their ankles from a helicopter must have been a shoo-in for the award’s judges, securing the 2021 Ig Nobel Transportation Prize. But while hanging rhinos produce spectacularly absurd photographs, a severe business lies behind the prize and the study.
Rhinos are in trouble. There are five species of rhino, and all are endangered. The three-tonne white rhino is the least endangered, yet only an estimated 20,000 are left in the wild. The species hung upside-down in the study is the black rhino, weighing 1.5 tonnes and with an estimated population of just 5,000. In attempts to protect rhino populations, conservationists have tried dehorning (to try to make rhinos less desirable to poachers), translocation (moving rhinos, including upside-down via helicopter), and even resurrection (creating embryos from the eggs and sperm, or even the DNA, of dead individuals).
We translocate rhinos because they live in guarded, fenced areas to keep them monitored – and protected, in theory, from their main threat from poaching for rhino horn. But this prevents animals from colonizing new areas, recolonizing vacant areas, or mixing genes between regions. So conservationists must lend a helping hand – or helicopter – to place rhinos into new areas. But until the Ig Nobel Prize-winning study, we weren’t entirely sure whether this upside-down transportation was safe for the rhinos involved.
HANGING HERBIVORES
The capture and translocation of large mammals can be dangerous and disruptive to the animals’ welfare. The entire capture and translocation process can result in psychological and physiological stress. Big African mammals, including elephants, giraffes, and rhinos, are physiologically sensitive. If such animals are given too great a tranquilizer drug dose or are left in the wrong position under tranquilization, they can die. Historically, wildlife translocation methods were informal and experimental, with successful strategies spreading by word of mouth. Formal scientific research has replaced this ad-hoc approach, supporting perceived wisdom or providing novel innovations.
So it’s essential, for animal health and welfare reasons alone, for the procedures applied to catch and move big animals to be as safe and non-disruptive as possible. African rhinos have been translocatedfor several years by hanging them upside-down, suspended from a helicopter, blindfolded, and under tranquilization. As well as enabling the capture and short-distance transfer of rhinos from areas inaccessible by road, transport by helicopter can mean shorter journey times, so it can be preferable for the rhino where it’s practical. Ut no one had ever established whether hanging upside-down is harmful to rhinos. Sure, rhinos appear fine when woken up at their final destination – but are they OK after that?
It might sound funny to deliberately hang 12 black rhinos upside-down for 10 minutes to monitor their physiology. But if nobody does the research, nobody knows whether it’s a safe way to transport an endangered animal. This is where science comes in. The Ig Noble Prize-winning study compared rhinos’ respiratory function and metabolic effects when their ankles hung them to when the same animals were lying on their sides. The researchers found that the respiratory efficiency of rhinos depended upside-down is, if anything, slightly better than when rhinos are laid on their sides during tranquilization. So, the process is affirmed as at least as good as traditional methods of transport.
RHINO RELOCATION
I have been involved in numerous white rhino capture and translocation operations in South Africa for my research: collecting blood and saliva samples to evaluate physiological stress associated with capture. The teams I worked with also used helicopters to dart the rhino with a tranquilizer from the air. The rhinos were woken up as soon as possible before walking them, blindfolded and ear muffed, onto crates for road transportation by truck to locations many hours away. During long-distance rhino transportation, it’s neither economical nor healthy for the rhino to remain tranquilized – so road transport is preferred.
