Why do we never see a sweaty elephant? Science keeps discovering new reasons.
The swimming pool at Pafuri Camp is a life-saver on a summer day. After a dip, the feeling of a light breeze on wet skin is deliciously cooling. A few metres from the decking, the Luvuvhu river flows strong after seasonal rains, and we never lose appreciation for just how much African wildlife we can see from the poolside recliners.
Recently, a herd of elephant entertained us with watery antics, the young ones dashing about knee-deep, kicking at the flow, sounding their fun. The females and older juveniles inhaled and sprayed torrents of brown water in the air, drenching their backs amidst much flapping of ears and tails. There is no mistaking the pleasure they get in a refreshing bath on these sultry days.
As they moved up-river, they passed immediately below the pool area and I was able to study them close up, seeing every bristle defined, their skin scored like a dry lake-bed. I recalled some interesting pachyderm facts that my guide Ezaya had mentioned on a previous close encounter.
Unlike us, most mammals can’t sweat, but have developed other ingenious cooling mechanisms. For elephants, one way is using those long wiry hairs to conduct heat away from the body. In every other mammal, hair acts to keep the animal warm, so this is a unique adaptation for elephants, and only recently discovered.
The animals were now so close that I could hear the gentle waft of ear movement. While the bristle cooling was news to me, I was more familiar with the reasons for the gigantic ears and how they regulate temperature. As Ezaya told me, the ears basically work like the radiator on a truck. They account for 20% of an elephant’s surface area and as well as operating as fans, they dissipate heat quickly. The air movement across the veins cools the blood as it circulates, and the animal can fine tune this process by dilating the vessels and pump up to 12 litres of blood through the ears every minute.
The most interesting cooling adaptation is in the elephant’s skin structure, and it is another new scientific discovery. The calves look like they have smooth skin, but in fact the sublayer (the dermis) is rough and has little protrusions called papilla. Dead skin cells do not shed but instead build up over the dermis in a layer known as the stratum corneum. As the animal ages, that layer gets very thick, and flexing causes cracks to form between the protruding papilla. An adult elephant’s epidermis is about fifty times as thick as ours.
Sporting a couple of ox-pecker birds on her head, one of the older lady elephants paused mid-stream and we made eye contact. She glistened in shades of slate, a muscular mass. I took a hard look at her skin patterns and the creases that are part of her secret cooling mechanism. Instead of quickly evaporating, the muddy water filters through the cracks in a capillary action and is stored. Scientists estimate that elephant skin retains ten times more moisture than smooth skin, and the outermost layer dries into a mud pack that keeps parasites at bay. When water is short, a dust bath will do the job of protecting from sunburn and insects. With each trunk-full of river water, the ladies are not just moisturizing, they are teaching their young ones important skills to keep them healthy for a long life.
With the challenges of climate change already evident, it’s nice to believe that elephants will adapt, as they are clearly intelligent. Regardless of good rains this summer, Southern Africa is gripped in a multi-year drought, and elephants are vulnerable. Some have been seen to rear up on their hind legs to reach tree branches that would usually be reserved for giraffe. Surely the young ones will see that behavior and remember it. As evidenced by the new research discoveries, there is still so much to learn about the natural world and its workings, which is one of the reasons we love being here.
A deafening elephant squeal disturbed my thoughts – two juveniles playing chase, churning up the muddy shallows. Suddenly the heat of the sun felt heavy, and I turned and slipped back into the pool, happy in my own skin.
Written by resident blogger: Hlengiwe Magagula
Feature Image: Anastasia Pashkovetskaya
Image 2: Anastasia Pashkovetskaya
Image 3: Anastasia Pashkovetskaya