Just how do Africa’s animals stay cool?

Africa can be a tremendously hot place at certain times of the year and the lowveld of South Africa, where the Greater Kruger National Parkis found, is no exception. In fact, it can be one of the hottest places in sub-Saharan Africa! This means that animals that have evolved on the continent have had to come up with some fairly interesting ways of keeping cool. Now, of course I can’t write about every single one of the them, or we would be here forever. I have therefore chosen a few species that I find most interesting and I hope you do to! However, it is important to mention that much of what I will write about here is based on theory, and on-going scientific study.

Let me begin with probably the most interesting, well at least in my opinion: The Plains Zebra! There are few things more iconic for Africa than the zebra, but behind that gorgeous stripped coat is a host of reasons for it.

Tanda Tula - zebra in black and white in the Greater Kruger

I could ramble on and on about the uses of this coat, but today we are talking about thermoregulation, which is just a fancy word for maintaining one’s core temperature. Now zebra are mammals which makes them warm blooded. This means their body can self-regulate its heat, but when you are dealing with environments that often drift over 40 degrees celsius (or for our American friends, 104 Fahrenheit), you need to employ a bit of back-up and that back-up often comes in the form of how an animal looks or its exterior anatomy. This is where those stunning white and black stripes come in.

Tanda Tula - zebras together in the Timbavati

Now we all know that black attracts heat and white repulses it, but zebra are probably pretty evenly black and white and so, this would defeat the point. However, what few people do not always realise is that zebra, like horses, sweat. And it is this sweat along with the difference in stripe temperature that add up to a remarkable cooling affect. You see, as the black stripes get warmer than the white stripes (and they can be by several degrees) a minute convection current begins to form as the warm air coming off the black stripes becomes attracted to the cooler air coming off the white stripes. This is basically a very small flow of wind that spurs on the evaporative cooling affect of sweating to a much greater effect. Pretty cool right? Sorry I had too.

Many of you may be wondering why zebra don’t just head for shade during the hottest parts of the day. Well they do, but because their digestive system is fairly rudimentary and inefficient, it means they need to spend most of their day feeding. Sadly, they feed on grass and so they need to spend most of those feeding hours in the direct sunlight. However, this is a subject for another day all together.

Tanda Tula - zebra running in the Greater Kruger

Let us now turn our attention to the largest of all terrestrial mammals, the African elephant! Elephants essentially have the same digestive system as the zebra, which by the way is called “hindgut fermenting”. So, like the zebra, they also can’t enjoy the shade for the most part. This leads me to an interesting thought process between African and Asian elephants, which I will get into a bit later.

Elephant skin has an incredible adaptation, it is the biggest of their organs and what it does for the animal’s thermoregulation is incredible. I will explain this first. For those of you that have ever been up close and personal with an elephant you would have no doubt admired its skin and all the wrinkles and for lack of a better term, crevasses, that make up this very mobile outer layer.

Tanda Tula - elephant tail on safari in South Africa

And mobile it is! When you weigh in excess of four metric tons, your skin better be very well adapted to allow you to move your incredible mass around, but we are here to talk about cooling, before I get ahead of myself! Elephants love many things, but two of these are water and mud, and this is where those wrinkles and crevasses come in rather handy. You see, elephants will just about every day, during the hotter months, make their way to water or mud, not only to drink but also to douse themselves. However, shortly after they leave the water source the surface of their skin already begins to dry, how could it not in such hot conditions? For several hours after that glorious swim and/or sprinkler party, the wrinkles work their magic. Essentially entombing the mud and moisture, acting as a sponge of sorts. Therefore, allowing the massive pachyderm to enjoy the cold mud for hours to come!

Tanda Tula - elephant in the Timbavati

There are a number of things that make elephants so famous, one of them being their ridiculously massive ears. Their ears can be used from a number of things from visual communication to thermoregulations and yes, even hearing! Their ears are super thin, cover a huge surface area and filled to the brim with blood capillaries and vessels. What this allows them to do when it gets a bit too hot, is to pump their blood through those ears consistently while flapping them through the air. This, of course, allows the blood to become cooled as the air gushes past and is then pumped back through the body in an effort to maintain a suitable core temperature. They act like a radiator in essence and on windy days, all the animal needs to do is stand with their back to wind and open its ears, thereby saving a little energy while keeping cool.

Tanda Tula - elephant cooling himself in water

This is where my thought process on the difference between African and Asian elephant ears comes in. They are both incredibly similar animals with almost identical anatomy, however, and I say this proudly, the African elephant is the biggest both in general stature and in ear size. But why the difference in ear size? After all, when I say “difference” I mean at least two or three times bigger! Well perhaps it has to do with the fact that Asian elephants have a lot more shade to work with than African elephants. Our elephants have to make do with wide open spaces of savanna while Asia’s elephants have to survive in rather shaded over jungles, for the most part at least.

For the last animal, I decided to shine a bit of light on one of Africa’s most overlooked species. An antelope that occurs in incredible numbers and has been referred to as “the perfect animal”. The reason for this is because they have essentially remained evolutionarily unchanged in over 5 million years!

Tanda Tula - impalas on safari

When I said earlier that they occur in incredible numbers, I really meant it. Estimations put them at about 120 000 in the Greater Kruger National Park alone! What this means, is that people get to see them, and people see them a lot. In turn, this means we often just drive right past them in search of the more elusive species, but they are actually very interesting animals that I feel need a bit of limelight.

One doesn’t actually consider very often how any animal keeps cool, let alone the impala. However, they have developed a rather ingenious way to fight off the African sun. For one, they have a completely different digestive system to elephant and zebra. This digestive system is call “rumination”, which you may remember from one of my previous Safari Science videos. To put it basically this digestive system allows the animal to seek shade far more often than their hindgut fermenter competition, because it is just astoundingly more efficient, which means they have more time to relax during the hottest hours of the day.

Tanda Tula - lonely impala on safari in the Greater Kruger

Africa is still a hot place though, whether you are in the shade or not, and even when you have a very efficient digestive system you still need to contend with the sun. Thus, the impala has once again turned to its external anatomy in order to make life more manageable. When you look at the above image, you’ll see that the animal is comprised of a number of colours with the most prominent ones being brown on the back, beige around the mid-section and finally white on the belly. All these colours play a part in the life of the impala, but it is obviously the white that helps with thermoregulation. You may have heard before that some of the deadliest sun rays around are those which reflect off other things? Well, soils in Africa tend to be pretty reflective, often having a shiny granite make-up. So, the evolution of the impala has chosen to rather reflect these sun rays away from the belly in order to reduce the heat build-up in the animal. Now, of course, if there was no such thing as predators then there would probably be a lot more white found on animals, but at the end of the day, many animals have had to find a good balance between camouflage and keeping cool, and this just so happens to be the perfect case study for that! Think of it as an “anti-solar panel” of sorts.

Tanda Tula - jumping impala on safari in South Africa

There are many animals that have developed various ways to keep cool and it happens to be one of my favourite things to think about when I am out on safari. Maybe when you are next out there you will now have a new area of thought as far as how animals survive. Who knows, maybe it will even spur you on to think about animals from differing thought processes as well?