Recently, I asked readers which colour scheme they preferred regarding the reworked Prober and Bobbuck (P&B) painting, giving them three choices. The one I chose in the end was the ‘African dawn scheme’, with strong yellow and orange as the main colours. If you see such colours in photographs from Africa, you can be almost certain that the photograph was taken at dusk or dawn against the light. There is always dust in the air in a dry climate, and if you look against the sun, that dust provides the yellow-orange glow. The P&B image tries to catch that feeling, and this is also why the sun is low and we are looking into the light.
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| Click to enlarge; copyright Gert van Dijk |
Anyway, I kept part of the prober’s colours bluish, if only to provide some contrast to the otherwise overly monochromic painting. I read a few recent papers about camouflage patterns to see whether there were new developments (here is a recent textual review without figures as examples). The major theme of that review was that many mechanisms can be combined. The P&B painting shows several mechanisms: background blending, countershading, disruptive colouration and probably a bit of motion dazzle.
Background blending is just what the words suggest, meaning an animal has colours and patterns that make it inconspicuous against the background. Countershading is simply having the underside of the body colour lighter than the top. As the belly of an animal will be shaded by the body, shade makes the light belly colour seem darker, and if all goes well, the result is that the belly is just as dark as the top of the animal. This helps with background blending and makes the animal lose its three-dimensional appearance. Disruptive colouration means an animal has patches of colour that make the overall shape of the animal more difficult to discern. This works best when the colours of the various patches also appear in the background. Many of these effects work best when an animal is motionless, but apparently some also work when an animal is in motion. In fact, ‘motion dazzle’ describes the effect that the motion of patterned objects is more difficult to judge than that of bland, unpatterned objects. (tis is not the same as motion camouflage).
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| Click to enlarge; copyright Gert van Dijk |
Back to Furaha and to the P&B painting. The prober and the bobbuck both show multiple camouflage features. Countershading should be obvious in both. Without thinking much about it, I made the belies of both animal an even light colour, whereas I could simply have continued the patterns on the rest of the animal but in lighter colours. Apparently, this occurs in Earth biology a lot too (from where I had unconsciously picked it up). The bobbuck’s horizontal stripes mimick the low hills and patches of low vegetation in the plains where it lives and may also help provide motion dazzle. The stripes are broken, both to break up the outlines of the legs and to increase the resemblance with natural features. The prober has a combination of stripes and spots that again help to break up its outlines. You may note that the stripes are largely at right angles to the animal’s contours. By the way, when stalking and in its initial attack run, the prober holds its ‘raptorial appendages’ (its graspers) back and down, closer to the centre of gravity. Its bright undersides are then not visible from the front. Probers only bring the graspers forwards to the attack position when the hunt is on, when camouflage is no longer an issue.
Does it all work? You may have noticed that I changed the header of the blog to reflect the updated P&B. Somewhat to my surprise, the shape of the animals is not immediately obvious on such a small picture. That may be because of their fairly unearthly shapes, motion blurring and camouflage. I like it myself, but perhaps I overdid it.
Was there anything else? Let’s see… Oh yes, both animals of course show features of the Great Hexapod Revolution (here and here), with their kinked distal and proximal necks. You may also note that the functions of the vertical (upper and lower ) jaws are separate from those of the horizontal (left and right) jaws. You will not find advanced hexapods in whom all four legs come together to catch prey; doing so poses overly complex demands on how teeth should work together, so the lateral jaws evolved into food gathering aids. If you look closely, you can see that the prober’s oesophagus runs alongside the proximal and distal necks, and not underneath the joints. You may have to wait for The Book to see that level of detail though.
Speaking of The Book, there is progress. Amazon’s self-publishing scheme makes it difficult to predict colours and shades on the printed page. The only way to get a useful result seems to be to change the colours beforehand, in expectation of then the printers will do with them. Or to them. As this takes trial and error using proofs, I am now at the fourth round of adapting colours, saturation, and brightness, among other things. On screen the results now look garish and cheap, but the proofs are slowly approaching how I wish them to look.
