
To Lions, Zebras Are Mostly Gray - Hooke
http://www.theatlantic.com/science/archive/2016/01/to-lions-zebras-are-mostly-gray/427050/?single_page=true
======
mintplant
> The idea that its black-and-white coat might help it blend in rather than,
> say, stand out seems preposterous, but there are two ways in which this
> could work. First, the black stripes could match dark tree trunks while the
> white ones match shafts of light between the trunks. Alternatively, the
> stripes break up the zebra's outline, making it harder to identify as a
> juicy piece of horse-shaped steak.

I always heard that it makes it difficult to discern individual zebras when
they're gathered together in a herd, confusing their would-be predators.

~~~
hammock
Check out razzle dazzle, visual camouflage for ships

[http://news.usni.org/2013/03/01/camouflaged-ships-an-
illustr...](http://news.usni.org/2013/03/01/camouflaged-ships-an-illustrated-
history)

~~~
theoh
Dazzle camouflage is fun but, at least originally, based on kind of specious
logic.

"I suddenly got the idea that since it was impossible to paint a ship so that
she could not be seen by a submarine, the extreme opposite was the answer – in
other words to paint her, not for low visibility, but in such a way as to
break up her form and thus confuse a submarine officer as to the course on
which she was heading."

Thinking in opposites is an insidious trait that plays a big part in art and
culture... but not in technology.

The dazzle scheme sounds more reasonable in this account:

"Wilkinson writes that “the painting of ships with the ‘Dazzle’ scheme is
based on the general assumption that it is impossible to obtain invisibility
at sea, especially where, as in the case of an attacking submarine, the object
is seen against the sky with practically no sea to form a background…the only
course open is to paint her in such a way as to deceive the attacker as to her
size and course; this can only be done by extreme contrasts of colour and
shapes which will so distort the vessel as to the symmetry and bulk.” (A Brush
with Life)"

~~~
Retric
It's not based on opposites.

Subs needed location and heading to sink a ship. They realized that gross
location was out, so heading became the next target.

~~~
theoh
Norman Wilkinson, the developer of dazzle camouflage in the UK, had a flash of
inspiration while sitting on a train that an "extreme opposite" approach was
required. As someone who deals with artists a lot, I can only express my
strong feeling that this was not a rigorous strategic insight. Creative, yes.

In fact there appears to be no conclusive proof of the perceptual
effectiveness of dazzle painting. Great for morale, though!

I'm open to hearing alternative accounts.

~~~
KineticLensman
My understanding is that the camo was intended to confuse WW1 sub captains who
were trying to compute torpedo firing solutions in their heads whil peering
through the periscope. The target ship plainly would be highly visible but
it's speed and heading would be obfuscated

------
EGreg
All these "evolutionary arguments" \-- this isn't real science. It's just a
bunch of "just so" stories that are tested in some of the flimsiest ways (one
phenomenon demonstrated to a statistically significant degree -- therefore
that must have been "the reason for the evolutionary change").

Listen, tons of features that an animal has are not correlated so highly to
survival as to make enough selective pressure to make that feature come to
completely dominate a population. I am very skeptical of the widely "held"
assumption otherwise.

For example, lets say the human anorectal angle was specifically "evolved" for
pooping while squatting. Is it a "just so" story or did the exact anorectal
angle contribute SO MUCH to survival or reprosuction that it became the
standard for bipedal humans?

Consider just how much relative advantage with survival and replication any
given feature must have in order to come to dominate ALL the other features
that are competing in the population. And this is in just one area. During a
single reproduction, there are tons of genetic and epigenetic variables that
could be selected for, which determine different things. Why would a specific
feature in a specific part of the body, that provides merely a minor
improvement at any given time, come to completely replace all other genotype
expressions? I have never seen a good analysis of this, just hopeful
handwaving, especially in popular books like The Selfish Gene.

~~~
facepalm
Just because many people make up evolutionary just so stories doesn't mean
that there can not also be valid evolutionary explanations.

If you just say "anorectal angle evolved so that people poop squatting" it is
a just so story. To make it solid you have to show the context, history and so
on. For example, why is it an advantage to be able to hold your poop in?

A lot of things evolved out of serendipity and are not perfect, like those
arteries going up and down the whole long neck of giraffes to bridge a short
distance. But there are evolutionary explanations for it.

As for features related to survival: I think phases with more and less
pressure alternate. If you made a breakthrough, say you discovered skeletons,
or invented the iPhone, for a while you may have such a big advantage that you
can play around with lots of fancy variants. Eventually the rest of the world
catches up, pressure gets higher and the less efficient variants get weeded
out.

~~~
EGreg
Just having plausible-sounding evolutionary explanations isn't enough, though.
You also need a way to falsify the theory. There is a good essay about this
called Science as Falsification, by Karl Popper:

[http://www.stephenjaygould.org/ctrl/popper_falsification.htm...](http://www.stephenjaygould.org/ctrl/popper_falsification.html)

Otherwise how is it different from Marxism or Freud's theories? I can always
concoct an explanation in the context of my theory. That isn't science by
itself. It's demagoguery.

~~~
facepalm
You make a model, then you make predictions. If they fail, your model was
wrong. You can do that in evolution theory, even though you are mostly looking
at history. Maybe you predict that all birds should have tails at least 30''
long, then you look around and see that they don't. You can also look at the
way genes spread - I suppose you can compare the observed spread of a gene to
the spread that would be expected if it were random.

Nevertheless, once you see something unexplained (like zebra stripe), I
suppose you start with creating theories, then you try to verify them. Isn't
the article here doing exactly that?

~~~
EGreg
Yes and if the a particular theory of evolution were only 5 years old that
would be fine. But several classical formulations like the
[https://en.m.wikipedia.org/wiki/Modern_evolutionary_synthesi...](https://en.m.wikipedia.org/wiki/Modern_evolutionary_synthesis)
have been around for decades and various proponents around the world yell that
they are "as proven as gravity". A strange position to take when there was
little falsification. Your examples above serve to illustrate the point - they
are just _illustrations_ of how falsification _might_ look like _if_ it were
done. If the prediction and falsification framework was robust by now, you
wouldn't have to come up with made-up examples, there would have been tons of
them like there are for other, widely tested theories, even in biology

~~~
facepalm
I am not a biologist, so you shouldn't draw any conclusions from me not
knowing good examples or the state of verification.

Your Wikipedia link seems to mention evidence for the "modern evolutionary
synthesis", are you sure that there has been no falsification? Also, I have
heard that name for the first time today.

------
Jedd
Three or four times in the past week, there's been front-page stories on HN
that have reminded me of this.

Rob Newman [0] (UK activist / comedian) has recently been considering
evolution[1], particularly in response to the Selfish Gene approach to
evolutionary biology. He's not a fan.

Over the past couple of months his new radio show - the Entirely Accurate
Encyclopaedia of Evolution[2] - has been broadcast in the UK on the BBC - a
delightful combination of droll + biology/science in jokes + enlightenment.

Mentioned partly because it deals with these kinds of claims in the abstract.

Primarily because it deals with these kinds of claims specifically. In one
episode he speaks about Cyclosa tremula [3] spider, who builds spider replicas
from her prey - they are grey, while she is striped black & white (we finally
return to the zebra analogy). When birds come to prey upon her, she bounces up
and down quickly, turning herself grey - to match these replicas. He makes
mention of a throw-away phrase from another paper on the subject, suggesting
that Cylocsa tremula builds these facsimiles _out of loneliness_.

The point being that we can never really know what mechanisms other organisms
are using to evolve.

    
    
      [0] https://en.wikipedia.org/wiki/Robert_Newman_(comedian)
      [1] http://www.telegraph.co.uk/culture/comedy/10322813/Robert-Newman-The-universe-Richard-Dawkins-imagines-couldnt-exist-for-five-seconds.html
      [2] http://www.bbc.co.uk/programmes/b06jm72p
      [3] https://en.wikipedia.org/wiki/Cyclosa

~~~
goldbrick
This is a really scary movement, not only because he's blatantly straw-manning
both Dawkins and Darwin, but because he's a populist without proper scientific
credentials subtly pushing an agenda -- we could call him the Glenn Beck to
Russell Brand's Joe Rogan.

Nobody properly doing science ever suggests that we ever have all the answers
and it frightens me that celebrities are so often given a podium of regressive
anti-intellectualism on which to challenge the corpus of established
scientific knowledge _and even to misrepresent it_.

~~~
awl130
I agree with your point and will add that such movements are not isolated to
the non-scientific: Dawkin's use of his own public platform to push his own
shockingly bad agenda. Which is to say, emotional outbursts of any kind are
noise and cancel each other out in time.

~~~
nitrogen
Which shockingly bad agenda would that be?

~~~
awl130
anti-muslim. just read his tweets.

~~~
PKop
What is shockingly bad about being against that ideology? It seems pretty
regressive and oppressive, to women, for example.

------
bauc
I read some interesting research[1] where they modelled the movement of
Zebra's and noticed that the stripes can create optical illusions by making
them appear to be moving in the opposite direction to what they actually are.

[1] [http://www.bristol.ac.uk/biology/people/martin-j-
how/pub/197...](http://www.bristol.ac.uk/biology/people/martin-j-
how/pub/19703495)

------
rocky1138
I feel like with a headline such as this, there should be a picture at the top
of what a lion might see when it looks at a zebra.

