Scientists and researchers have come up with a new way to aid rhino-protective efforts thanks to rhino research that’s set to help these animals be as safe as possible when undergoing procedures!
Pretoria, South Africa (15 August 2024) — In the relentless battle to protect rhino species and ensure their survival (which is always at ends with poachers), researchers at the University of Pretoria have made an eye-opening breakthrough in their rhino research–quite literally!
Efforts to protect rhinos vary. But two common practices are dehorning and relocation, with the former requiring routine but delicate procedures.
The problem is that wildlife vets have not had an effective way to measure and the rhino’s blood oxygen levels when they are immobilised—using blood gas analysers and pulse-oximeters designed for humans.
Of course, a 1.5 to 2.5 tonne rhino is slightly different to a human—making this means of measurement a big challenge in the field. Because blood oxygen levels can drop dangerously low when under anaesthesia (immobilisation drugs can impact the animal’s heart and lungs) the catch-22 is this: the means of dehorning a rhino in an effort to save its life also putting this life at risk?
Enter the UP scientists and their out-of-the-box rhino research.
The new research shows that pulse oximeters (originally designed for humans) appear to be a more effective means to measure rhino blood oxygen levels when they are attached at an unusual site: the rhino’s third eyelid!
This is the crescent-shaped fold of the outer eye structure that forms a thin, semi-transparent, almost ‘blinking’ membrane of the eye, as Dr Thembeka Mtweta explains.
“To give the pulse oximeters the best chance of working, we had to think carefully about where to place them on the rhino’s body—where the animal’s skin and membranes aren’t too thick,” explains Dr Mtetwa.
“In humans, the third eyelid is that little pink structure snuggled in the corner of your eye that is barely noticeable – it is vestigial and has no function, but in rhinos, it is, of course, much larger, and it contains lots of small blood vessels. It’s also quite noticeable in dogs, cats and other animals; it functions to protect and clear the eye of foreign bodies when it closes, and to help keep the eye moist.”
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The group tested the reliability of different pulse oximeters at various attachment sites on the body of an immobilised rhino with the third eyelid proving to be promising.
Prof Meyer, who has more than 20 years of experience in wildlife chemical immobilisation, came up with the novel idea to give the third eyelid a go.
“The colour, moisture and capillary refill time of the external mucous membranes of the body are good indicators of hydration, circulation and the overall health of the animal, and are typically good sites to place a pulse oximeter probe,” he says.
“However, making use of these membranes on a rhino can be challenging due to their thickness and poor accessibility in some locations of the body, like the mouth. That’s why we decided to explore the mucous membranes of the third eyelid as an alternative option. Luckily, it turned out to be a good idea!”
“The great thing about the rhino’s third eyelid is that it is relatively thin,” Prof Snelling adds. “It has lots of blood vessels close to the surface, and it’s easy for vets and vet nurses to access it.”
“Our findings highlight the importance of using appropriate monitoring techniques in large immobilised animals like rhinos, which have unique anatomical and physiological characteristics,” Dr Mtetwa says. “This new research improves our ability to provide care and ensure the well-being of rhinos in the field.”
Meanwhile, in more good news for rhino protection, an organisation has teamed up with AI to help track rhinos in trouble faster than ever! Read all about it here.
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