Sunday, 8 July 2012

Elephant No. 280: Crayon Drawing

I wanted something easy for today's elephant, so I decided to draw with one of the simplest things around: wax crayons.

Since I've already written about the history of wax crayons, I'll just describe today's technique.

I was originally going to just draw with crayons. Then I decided that, to make things more interesting, I would draw with crayons, then blend the drawing with heat. I guess it's sort of a modified encaustic idea, the difference being that encaustic wax is usually heated before it's applied.

I started with a box of Crayola-brand crayons. This time I think I may actually use the built-in crayon sharpener.

Because I wanted to end up with something relatively realistic, I drew from a photograph. This is the photograph I chose:

African elephant, Miami.

I began by sketching a light outline with crayon on a sheet of mid-range watercolour paper.

Once I liked the look of this, I added a bit more orange. I thought this might be a good point to start blending the wax with heat. I decided to use my soldering tool, with a flat tip.

This did nothing. Nothing. I thought maybe it was because I needed to have more wax to melt. So I drew some more.

I tried melting the wax again. Still nothing. So I drew some more. Surely, I thought, I could make a nice blending effect with the thick purple crayon shading. Nope.

I tried a hairdryer next. This has the net effect of softening the lines ever so softly. So softly, in fact, that it's barely perceptible.

I gave up on my blending-with-heat idea, and I didn't want to use blending stumps. Instead, I concentrated on just finishing the drawing with crayons. I used six colours—three primary colours and three secondary colours. The crayon colours I chose were some of my favourite Crayola colours: violet-red, violet-blue, dandelion, red-orange, pine green and royal purple.

In the end, the drawing took me about an hour and a half, about fifteen minutes of which were spent playing with heat. Although I was disappointed not to be able to blend as I had envisioned, the final drawing is nice enough, and I was actually a bit surprised that I could produce something that looked like a fine-art drawing with kids' crayons.

Elephant Lore of the Day
Because elephants have thick hides and no sweat glands, scientists have long thought that elephants relied on their ears to cool themselves. The fine network of veins throughout the large ears was believed to help conduct heat away from the elephant's body, and the flapping of the ears was thought to provide a cooling fan effect.

Recent research, however, has determined that an elephant's cooling system is far more sophisticated. Elephants actually have "hot spots" throughout their bodies. These small patches of skin, located near the surface, allow an elephant to direct its blood supply and fine-tune its internal temperature.

Large animals tend to retain heat because they have a relatively small surface through which heat can escape. In elephants, this is further complicated by the intense heat of their natural environments, a lack of sweat glands, and a thick hide designed to protect them from being scratched and cut in the undergrowth. Because an elephant's ear skin is thinner and laced with veins, blood in the ears cools quickly, in turn helping to cool the animal.

Researchers in Vienna took thermal images of six African elephants in the Vienna Zoo, studying how temperatures on the skin surface changed as the elephants moved between their indoor and outdoor environments. Their findings were surprising. In addition to large "hot spots" in the ears, the elephants had as many as fifteen more such areas across their bodies. The hot spots actually grew as the air temperature rose, indicating that more blood was flowing to the skin surface to help cool the elephants.

Subsequent studies showed that the phenomenon seen in zoo elephants was replicated in the wild. It has been speculated that the location of the hot spots may actually provide localized cooling for specific internal organs. In the image below, the light yellow-white areas indicate the warmest areas, whereas purple and blue indicate the coolest.

Thermal image of Asian elephant.
Photo: Arno Vlooswijk/Coen Boonen

So precise is this collection of cooling strategies that elephants are able to keep their body temperature at about 36˚C (96.8˚F), a degree centigrade lower than humans.

In a similar study at Busch Gardens in Florida, scientists studied the ways in which elephants cast off heat at night. Interestingly, the hottest part of an elephant at night is the surface of its trunk, which appears to be the most important cooling mechanism. By contrast, the ears have almost no role in cooling down an elephant at night. In the image below, red indicates the warmest areas, whereas blue indicates the coolest.

Asian elephant cooling off at night, Busch Gardens, Florida.

To Support Elephant Welfare
Elephant sanctuaries (this Wikipedia list allows you to click through to information
on a number of sanctuaries around the world)
Wildlife Trust of India

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