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7/29/2019 Colour strategies in Nature
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COLOUR STRATEGIES IN NATURE
ABOUT THE USE OF COLOUR IN NATURE
STRATEGIES BETWEEN MIMICRY AND PROTAGONISM
a text by Francesca Cremasco
MIMICRY / CAMOUFLAGE / IMITATION
The word ‘mimicry’ is derived from the Greek ‘mimetizo’ which means ‘imitation’. In nature it indicates the phenomenon
in which an animal takes colours, forms, behaviors and other characteristics to be similar to the environment around it,
or to another animal. Mimicry is one of the most interesting and complex phenomena within environment adaptations
aimed at survival.
If an individual does not adapted to the environment in which it lives, its chances of survival and reproduction are
minimal. A very similar colour to the surrounding environment is beneficial in escaping predators, but also to avoid being
noticed by an animals’ potential victims. Body color is often linked to the needs of the struggle for existence.
Animals may
have
two
types
of
camouflage,
one
with
the
aim
to
hide
(survival,
protection)
and
the
other
with
the
aim
of
modifying appearance and recognition (predation and reproduction).
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The first is known as cryptic mimicry (from the Greek kriptòs = hidden) and refers to the process of a subject physically
adapting to its surrounding environment, or becoming part of it, in order to hide or become invisible. Some animals
authentically mimic the colors and the shapes of leaves, flowers, wood or rocks.
The second type is known as the faneric mimicry (from the Greek phaneros, manifest) and occurs when an advantageous
feature is “copied” from other species for predation. Faneric mimicry may be ‘batesian’ and ‘müllerian’ .
With batesian mimicry (the name derives from Henry Bates who first discovered and reported this phenomenon) a
harmless species
is
protected
by
its
resemblance
to
one
or
more
dangerous
species,
noxious
or
unattractive.
This
type
of
mimicry functions as a defensive strategy. This type of system may evolve if models and mimes coexist in time and space,
and share a similar lifestyle.
With mullerian mimicry (from Fritz Mulller) two or more species assume similar shapes and colours in order to not be
distinguishable, and thus by having similar colors predators quickly learn to chase both. Such “cooperation” allows a
mutual advantage to these species, as the predators must learn only one signal. In this way every single species is preyed
on in smaller quantities.
FUNCTION / TYPES OF STRATEGIES
In order
to
understand
mimicry
in
its
true
sense,
it
is
important
to
look
at
each
function
of
the
various
camouflage
types,
and their effects . The function connects and organizes all the parts into a system and identifies a strategy. Each part
(such as the form, colour, motion etc.) can have different meanings depending on the specific context of relationships.
This is crucial because similar pattern types (e.g. blotches, stripes) may have entirely different functions in different
animals and circumstances, ranging from camouflage to warning and sexual signals.
The main forms of visual camouflage1:
Background matching: where the appearance generally matches the colour, lightness and pattern of one (specialist) or
several
(compromise)
background
types.
When
a
subject
has
the
same
color
(monochromatic)
as
its
environment
there
is
an identification of figure and background (examples are frogs, caterpillars etc. ...). This process can happen even with
the borrowing of materials from a context (like fish camouflaged in the sand). Another example is when the livery
matches several background types. This can happen in two ways, one considers the subject and its environment (like a
leopard in the savannah), the second regards a group of subjects rather than the individual. This difference leads to
specific configurations of livery. In the first case the pattern takes colours and forms from the surrounding context, but in
the second case the pattern performs its function through the dynamics of the group, through the multiplication of
subjects. For example, the striped pattern of the zebra produces an optical illusion, which makes it difficult to recognize
the single subject. The “disguise” is optimized not only for the environment but also for group behavior of herd animals.
Counter shading (obliterative shading and self ‐shadow concealment): a counter‐shaded animal possesses a darker
surface on
the
side
that
typically
faces
greater
light
intensity
and
a lighter
opposite
side.
Counter
shading
appears
to
be
involved in several functions, including the compensation of the animal’s own shadow (self ‐shadow concealment),
simultaneously matching two different backgrounds in two different directions (background matching), changing the
three‐dimensional appearance of the animal (obliterative shading). In self ‐shadow concealment the creation of shadows
is cancelled out by counter shading, and obliterative shading, where the creation of shadow/light cues for the three‐
dimensional form of the animal are destroyed.
Disruptive coloration: being a set of markings that creates the appearance of false edges and boundaries, which hinders
the detection or recognition of an object’s, or part of an object’s, true outline and shape. A typical example is a body
coloration that consists of high‐contrast markings that tend to break up the appearance of an animal.
1 Here the term camouflage is used to describe all forms of concealment, including those strategies preventing detection (crypsis) and those recognition
(e.g. masquerade).
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Flicker‐fusion camouflage: where markings such as stripes blur during motion to match the colour/lightness of the
general background, preventing detection of the animal when in motion.
Distractive markings: which direct the “attention” or gaze of the receiver from traits that would give away the animal
(such as the outline).
Transparency: where part of an animal’s body is transparent, reducing the likelihood that it will be detected.
Silvering: common in aquatic environments and where an animal’s body is highly reflective (like a mirror) making it
difficult to
detect
when
light
incidence
is
non
‐directional
(such
as
due
to
strong
scattering
by
water
‐borne
particles).
Masquerade: prevents recognition by resembling an uninteresting object, such as a leaf or a stick.
Motion dazzle: markings that make estimates of speed and trajectory difficult by the receiver.
Motion camouflage: movement in a fashion that decreases the probability of movement detection. An animal appears to
be stationary, ‘tricking’ the receiver’s visual system by moving in a certain way.
MAIN ASPECTS
The first important aspect of mimicry is the function (what it does), which is resolved through the synergy of many
different matters. The technical aspect of visual camouflage provides a specific solution to a desired function.
Function always
moves
from
some
foundational
aspects.
The
first
and
foremost
is
communication,
the
need
to
transfer
a
message. The color is the most effective mean to communicate and create an emotional state (attraction, fear,
protection, etc.). This fact implies the involvement of at least three subjects : an active subject, a passive subject
(receiver) and the environment, and each subjects can be single or a group. The first two subjects are involved in an
empathic relation and the space is used passively, it has a role of utility. The result is always a relation, which stems from
the specific needs and characteristics of the subjects.
Mimicry processes occur in a space and generate a space (of relations, of attraction, of warning etc.). What happens
during the process is perceived only by subjects involved, or by external parties capable of decoding the phenomenon,
therefore of having the same cognitive abilities.
The
strategy
of
imitation
in
nature
is
based
on
the
existence
of
a
model,
an
imitator
and
a
receiver
(the
subject
deceived
by the imitator). This process is in continuous evolution because the imitator tends towards a complete imitation of the
model, and the receiver evolves towards an increasingly accurate distinction of the characteristics of the imitator.
The cognitive abilities of the receiver are constitutive part of the process of mimesis. In the process of natural selection
what is decisive is the viewer’s perception, not our own, because it has created the selection pressure on the animal’s
coloration.
bibliography:
Animal camouflage, edited by M. Stevens and S. Merilaita, Cambridge University Press, 2011
Exploring Life Set, G.Brum, L. K. McKane, G. Karp, Wiley & Sons, Canada, 1994
Il mimetismo
animale,
Ward
P.
, De
Agostini,
Novara,
1979
web resources:
http://en.wikipedia.org/wiki/Mimicry
http://en.wikipedia.org/wiki/Animal_coloration
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exampleofcrypticmimicry
time
adaptationtotheenvironmentmaybecontingent
colour,
form
and
pattern
colour
someexamplesof
background
matching.
opticalillusion-falseeyes
Largespotsthatresembleeyesisafrequentdrawingon
thecoatofanimals.
Simulatepartsofthebodyindifferentpositionsserves
tolookbiggerandscarethepredator.
exampleoffanericmimicry
falseidentity
Smalldifferencesoncolourand
patternforappearhowotherspecies,
inadefensivestrategy
Someanimalstaketheappearanceofdangerousanimalsforintimidatepredators.Inothercases
thestrategyistheopposite.Somepredatorsmimictheprey(usuallythefemale)forapproachit
andcapture...
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CONTACT POINT
POSSIBLE MIGRATION OF FUNCTIONS AND TECHNIQUES
The concepts outlined above may suggest new perspectives on our environment. Changing one’s approach leads to a
reinterpretation of the places that belong to a vision almost codified, but also suggests ways for defining new functions
and relationships.
Below
I want
to
suggest
some
architectural
aspects
of
mimetic
processes,
and
how
they
could
lead
to
new territories of experimental design.
With regards to the spatial qualities of mimetic processes, in many cases we can see that the active subject aims to
simulate “other” spatialities (of the background, of the surrounding elements), or to conceal its three‐dimensionality. It’s
a sort of dematerialization and depersonalization, in order to assimilate the characteristics of spaces surrounding the
subject, through a complex flattening process. Background matching, countershading, disruptive coloration, flicker‐fusion
camouflage, transparency, silvering and masquerade all fall under this category. The constant element in these processes
is the interaction between active subject and the background or surrounding space. The active subject adapts itself to an
environment that is used in a passive way. Changing point of view, the subject is always in relation with surfaces, even if
the interaction is not functional and not designed. In mimicry, the colours and forms of livery are the most important
elements, supported also by the orientation of subject and the arrangement of its body parts in space.
Their position is linked to the point of view of the receiver, which can be directed in particular either to the horizontal
(from top to bottom), or to vertical planes (from high to low). The quality of surfaces (colours, shapes, developed along a
dominant axis) has an important role on perception of dimension ‐real, dilated or restricted. As explained above, in
nature the relationship status, determined by the specificity of the subject (defensive, aggressive, attraction etc.), is the
driver of the form of mimicry. In other words the type of relationship is the driving force of the project. Shifting the
concept to architecture, project development and design, relationships of various natures could emerge, i.e. elements,
people, places, and thus influence people’s reactions and behavior in relation to the various functions.
Position and
behavior
are
two
closely
related
concepts,
not
only
in
the
animal
world.
The
arrangement
of
subjects
creates
spatialities with different characteristics. Spaces of proximity, attraction or repulsion are generated through location and
orientation. The communication assets of colour helps to define the quality of the movement between the parts,
attraction, repulsion or distance. A signal of danger induces a user to keep his or her distance and vice versa, attractive
colours induce rapprochement. The qualities of the livery interact on the perception of the receiver, creating a
conditioned view. Strips, patches, “decorative” motifs guiding vision, sometimes cause a “distorted” perception, but
correspond exactly to the required function.
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SUGGESTIONS
In the subway there are spaces allocated to different functions (spaces where people walk and spaces for waiting) but usually the aspect does not
change. Surfaces are the background of these conditions. Rethinking the surfaces as places of interaction with figures could lead to new scenarios
and a new territory of exploration.
This type of situation is very common in urban places. The rear side of road platforms, tramlines or trains is a horizontal surface which dominates the
environment. A different treatment of these could affect the perception of spatiality. Acting on perception means acting on space. Urban margin
spaces could
be
converted
to
places
of
many
different
functions
or
just
evolve
into
something
suitable
for
human
environment.
case_1
relation
subject/background/
movement
case_2
countershading/orientation of surfaces
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Road barriers are a visual protection (to hide the road from the surrounding environment) and anti‐noise filter (cushion the impact of traffic noise).
Their condition is double (internal/external) in fact the perception and the utility is differently from inside and outside the street. The aspect of
surfaces could be designed for extend functionality. Through acting on shapes and colors of surfaces it is possible to determine a type of perceptual
relationship (concealment, decorative, communicative) . Outside the receiver could be near or far, standing still or in motion. This fact changes the
possible function and consequently the form of decoration (away from the barrier may indicate the presence of the road giving useful information,
but closely
the
decoration
can
be
viewed
in
a different
way).
In many buildings the appearance of the facade is dominant in urban spaces. There are many facades designed with visual codes now exceeded.
Acting on their appearance we could transform and deform the perception we have on them. Modifying figures, forms, colors, rhythms, it is possible
to guide the perception to something different without destroying the existing. Nature provides us with methodological examples and concepts (like
distractive markings, disruptive coloration etc.) so we can come up with new
techniques.
case_3
functions/movement/distance
case_4
affect the perception/re‐semantise
case_5
extend the
functions/space
in
the
shadows
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Animals use shadow to change the perception of their volume or to disappear. In many cases (as in historical places) we need to make invisible
interventions or minimize the impact on the existing elements. The relation of light‐shadow on architecture is of primary importance, rarely do we
look at the shadow before we look at the building thus not exploring the visual opportunities and signals of shadows. Through shadows it is possible
to re‐think spaces, equipment, roofing and many other typologies of elements which may cause shadows to hide, to confuse, to emphasize
surrounding elements.
Pedestrian underpasses should be visible, attractive and perceived as safe, the opposite of what often happens. Visibility of subjects outside and
during the passage is the most important aspect of feeling safe in a place. This case has an analogy with background matching, the one about
relation between subject and background. Light‐shadow and colors are the primary elements upon which we can work to influence the perception
of underpasses.
Different conditions/functions coexist in the same. The relation figure/ background can help isolate the subject from its surroundings and amplify
the attention to it. Concentration is the most important aspect when we are talking with somebody for a few minutes in a public office. Also the
division of spaces (not only physical but also sensory‐perceptual) is important for both conditions (waiting and action). During moments of
concentration, the space tends to lose its three‐dimensionality. Visual perception focuses on the close up. Also the acoustic isolation, which is very
important in terms of concentration, deletes the perception on three‐dimensionality of space. Space planning should lead to a correct spatial
relationship (proximity, distance), not only physical but also perceived.
case_6
emotional perception of
space/figure‐background
case_7
functions/spatiality/flattening
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CONCLUSION
Mimicry is a complex phenomenon that must be analyzed from many points of view, because simple and different
elements become the visual reply of complex interactions. Mimicry is a system of environmental adaptation, which from
time to time finds unusual functional expressions. The function is the place where elements are organized in a strategy,
which is the expression of characteristics and relations between the subjects involved in the mimetic process.
The subjects are of primary importance because they are the driving of the system. Every animal is an active and passive
subject at the same time, because each subject can be predator or prey for another subject. Mimicry primarily serves in
situations of conflict, where there is a contraposition of interest between individuals. The conflict take place if the
interest of a subject (active) precludes/conditions the interest of the other (passive subject).
Our environment (not only natural but also our built environment) has many places of contrast, some of which are not
immediately identifiable because of our ordinary vision. We often suffer the surrounding reality because we take for
granted the
modalities
that
have
generated
it.
Many
places,
spaces,
and
elements
that
appear
neutral
to
our
vision
are
instead actually strongly characterized. Mimicry often seems neutral, because of the visual depersonalization of the
subjects on the environment. It's a form of highly engineered neutrality.
Can harmonious coexistence come through a neutral project?
As social animals, which mechanisms can we actuate to adapt the environment to many different users?
Also, how could we be more adaptable to our current environmental circumstances?
In conflict conditions, which are the mimetic strategies that we normally use, and how much can our intervention
influence the environment?
Since our world is so strongly artificialized, is it still possible to refer to a natural world and adopt its strategies?