Clever

Helps to explain why the zebra has stripes:

Painting a cow to look something like a zebra has been found to reduce fly bites by 50%.

Which leads to something I don’t know. Tsetse flies mean chunks of Africa can’t be used for cattle raising, nor, I think, horses. Not so much the fly I think, but some parasite their bite passes on. (!?!)

Zebras are of course closely related to horses, it’s possible to breed a zhorse or summat, as with a mule from a horse donkey combination – and the donkey zebra cross is definitely possible – but what is it that leaves the zrbra free to breed in tsetse areas? Is it immunity to the parasite? Or being bitten less? And if the second, is that the reason for the stripes? Or even, did they develop before the immunity did.

And another question. I know there was a big trade in horses from the steppes down into India. And also from N Africa down into tropical.

Why?

Is it because horses don’t breed, or don’t do so well, in hot climates? Or just the economics of billions of acres of grassland?

12 comments on “Clever

  1. Did the traders sell only neutered animals to keep their customers paying? Similar stunts have been pulled before (tea plants had to be smuggled out of China to break the monopoly).

  2. The original research was on zebras, then someone thought they’d try it on cows to see if it works for them as well.

    Tsetse flies used to mean a large chunk of Africa wasn’t particularly good for humans either – sleeping sickness is the result of the parasite they can carry. Last time I was in Zambia I saw the remains of several villages which had been forcibly cleared out by the British in the 40/50s in an attempt to create a cordon sanitaire against the disease. Tsetses are bastards – mosquitoes avoid DEET, tsetses seem to regard it as a chaser for human blood.

  3. I’m sure I read about this in one of the Science of Discworld books, so that’s getting on for 15 years ago.

  4. Stephen Jay Gould’s essay “how did the zebra get its stripes” (collected in “Hen’s teeth and Horse’s Toes”) partly deals with this – basically, the potential for stripes is there in most horsey animals, and Zebras turned out to benefit enough from the potential becoming actual.
    Whether it’s camouflage, or confusing Tsetse flies, or one edging into the other, there was enough selection pressure in that direction.

  5. “Two of the cows were painted with white stripes, two with black stripes and two were left unpainted for a control. The process then repeated so, over nine days, each cow spent three days striped, painted black or unpainted”

    Clever pupil, shirley, certainly justifies an A and a place at Cirencester.

    but wait Zebras and tstse have co-evolved… so yeah if it works on Japanese cows for japanese cow flies, then sure go for it, but as far as Tim’s question is concerned, i’d posit the african biting flies are going to be somewhat harder to confuse

  6. Have they checked so see if it’s the paint the flies don’t like? Because I very much doubt it’s the stripes. Try painting them to look like leopards.

  7. I wonder if painting stripes on humans would help prevent terse fly bites? There are hundreds of people just lying in the road in London who, I am sure, would willingly volunteer if it helps the continuation of the human race, something they seem quite keen on.

  8. ‘Painting a cow to look something like a zebra has been found to reduce fly bites by 50%.’

    Going out on a limb here but… does the team think that the chemicals in the paint repelled the flies either by odour or on contact?

    And why aren’t all animals, including Humans in Africa, striped?

    The stripes on zebra as with other animals are generally attributed to camouflage which is particularly important for not being eaten and therefore for survival in animals that are preyed upon.

  9. John b,

    You would control that as best you could. By painting the control cows to look like cows.

  10. “You would control that as best you could. By painting the control cows to look like cows.”

    Which is what they did when they painted black stripes on black cows!

  11. @jgh October 11, 2019 at 9:55 am

    +1 Zebra stripes and flies is old news. Zebra stripes confuse predators (inc flies) – hence dazzle paint

    Also, many creatures do not see what we see, many are B&W, bees are UV.

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