Animal behaviour: Introduction to Ethology

S.Y.B.Sc. Sem III Course 07 (USZO303): Unit: 2 Ethology and Conservation Biology
Page 1 of 26 Presented by Dr. Sudesh Rathod, Associate Professor, B. N. Bandodkar College of Science,
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2.1: Introduction to Ethology
 Definition and scope.
 Nature v/s Nurture, Innate behavior and Learning
2.1.1: Definition and scope.
Ethology is the scientific and objective study of animal behaviour, usually with a focus on behaviour
under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Ethology is a
branch of zoology concerned with the study of animal behavior. Ethologists take a comparative
approach, studying behaviors ranging from kinship, cooperation, and parental investment, to
conflict, sexual selection, and aggression across a variety of species.
Understanding ethology or animal behaviour can be important in animal training. Considering the
natural behaviours of different species or breeds enables the trainer to select the individuals best
suited to perform the required task. It also enables the trainer to encourage the performance of
naturally occurring behaviours and also the discontinuance of undesirable behaviours.
Behaviourism is a term that also describes the scientific and objective study of animal behaviour,
usually referring to measured responses to stimuli or trained behavioural responses in
a laboratory context, without a particular emphasis on evolutionary adaptivity, popularly known as
classical conditioning, operant behaviour and instrumental behaviour.
2.1.2: Nature v/s Nurture
Behaviour occurs in an individual naturally or developed after a learning process due to
environmental influence or contingencies of the outcome. Natural behaviours in a species occur by
birth which otherwise known as innate behaviour. For example, a dog will salivate the first time—
and every time—it is exposed to food. The innate behaviours are usually stereotype and called as fixed
action pattern (FAP). FAPs are stereotyped behaviors that occur in a predictable, inflexible sequence
in response to an appropriate stimulus from the environment.
On the other hand the animals learn much behaviour after birth and these learning depend upon the
contingencies of the outcome. The improvement of learning is dependent on the outcome whether it
is positive or negative. Due to this reason the learned behaviours usually vary in individuals of a same
species. The variations in learned behaviour of an individual depend on the intensity of the
environmental factors impacting on it. Therefore it is true say that the environment nurtures the
learned behaviour in an animal.
2.1.3: Innate Behavior
Behaviors that are closely controlled by genes with little or no environmental influence are
called innate behaviors. These are behaviors that occur naturally in all members of a species

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whenever they are exposed to a certain stimulus. Innate behaviors do not have to be learned or
practiced. They are also called instinctive behaviors. An instinct is the ability of an animal to perform
a behavior the first time it is exposed to the proper stimulus. As mentioned above, a fixed action
pattern (FAP) is an instinctive behavioral sequence produced by a neural network known as
the innate releasing mechanism (IRM) in response to an external sensory stimulus called the sign
stimulus or releaser. One of the key ideas of classical ethology is the concept of fixed action patterns
(FAPs). FAPs are stereotyped behaviors that occur in a predictable, inflexible sequence in response to
an appropriate stimulus from the environment.
Fig. 1: Kelp Gull chicks peck at a red spot on their mother's
beak to stimulate the regurgitating reflex, another
example of a fixed action pattern.
Egg-rolling pattern of greylag goose (a)
Retrieval of a normal egg; (b) attempt
to retrieve a large egg or “supernormal
stimulus.”
Examples:
1. The tapping behavior is innate, or genetically preprogrammed. Herring gull chicks will peck
at the red dots of their parents' beaks without any prior training. In fact, a baby herring gull
can be fooled by a yellow stick having a red dot—it will peck at the stick just as eagerly as it
would at a parent's beak.
2. At the sight of a displaced egg near the nest, the greylag goose (Anser anser) will roll the egg
back with its beak. If the egg is removed, the animal continues to engage in egg-rolling
behavior, pulling its head back as if an imaginary egg is still being maneuvered by the
underside of its beak. It will also attempt to move other egg-shaped objects, such as a golf
ball, doorknob, or even an egg too large to have been laid by the goose itself (Tinbergen 1951).
3. Animals use fixed action patterns in communication: An example of how FAPs work in
animal communication is the classic investigation by Austrian ethologist Karl von Frisch of the
so-called "dance language" underlying bee communication. The dance is a mechanism for
successful foragers to recruit members of the colony to new sources of nectar or pollen.

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Fig.2: The honeybee's figure-eight dance is a fixed-action pattern that communicates
information to other members of the group: the angle from the sun indicates
the direction of a food source; the duration signifies its distance.
Features of Innate Behaviour:
 Innate behaviors are rigid and predictable.
 All members of the species perform the behaviors in the same way.
 Innate behaviors usually involve basic life functions, such as finding food or caring for
offspring.
 Innate behaviors occur in all animals. However, they are less common in species with higher
levels of intelligence.
2.1.4: Learning
Learning is a process of gathering Learning is process of acquiring information or knowledge from
surroundings. Learned behavioural pattern in an individual depends on the intensity of impact of an
environmental stimulus. It also depends on the outcome after a particular response. In general,
a learned behavior is one that an organism develops as a result of experience. The behaviour
intensifies if the outcome is positive or vice versa. Therefore every individual alters the action and
response to a particular stimulus dependent on its individual experience. Animals often learn through
observation, that is, by watching other animals. Observational learning can occur with no outside
reinforcement. The animal simply learns by observing and mimicking. Animals are able to learn
individual behaviors as well as entire behavioral repertoires through observation. Some information
or knowledge is acquired and is then used to alter the individuals actions and responses. Learning as
an adaptive behavior allows individuals to adapt to specific environment challenges. There are two
types of learning, namely non-associative and associative learning.
Non-associative learning
Non-associative learning is a mode of learning which lacks any association with positive or negative
reinforcement. This means they change their response to a stimulus without association with a

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positive or negative reinforcement. Most animals show some degree of non-associative learning. It
includes habituation and sensitization.
Habituation
Habituation refers to a gradual decrease in behavioral responses with repeated encounters of a
particular stimulus. Finally total elimination of response to a stimulus will occur. When presented
with a ‘novel stimulus’, the response is revived. This phenomenon in which the habituation
disappears is, conveniently, known as dishabituation. When the stimulus is unknown or unfamiliar,
the various animals responds to it vigorously and exhibit the behaviors associated with danger like,
hiding, remaining motionless, jumping, fleeing etc. but after repeated occurrence without any
significant meaning the stimulus loses its importance or novelty and is ignored by the animals.
Fig. 3: Reduction in response with the increased
number of trials of a stimulus.
Goose-Hawk silhouette model to exhibit
the impact of more frequent stimulus od
goose causing habituation
The classic example is of Hawk-goose model experiment in which when the silhouette was flown in
hawk direction the young chicks of turkey were alert and tried to escape whereas when the silhouette
move in goose direction the chicks didn’t react. This indicates that the turkey chicks were habituated
with goose shadow since geese are very common in nature and they often fly overhead. But the
shadow of hawk was strange for the chick and hence they were frightened.
Sensitization
In contrast, sensitization refers to an increase in behavioral responses following repeated
applications of a particular stimulus. Following sensitization, very little noble stimulation is then
required to produce exceedingly large effects. Eric Kandel was one of the first to study the neural
basis of sensitization, conducting experiments in the 1960s and 1970s on the gill withdrawal reflex of
the seaslug Aplysia. Kandel and his colleagues first habituated the reflex, weakening the response by
repeatedly touching the animal's siphon. They then paired noxious electrical stimulus to the tail with
a touch to the siphon, causing the gill withdrawal response to reappear. After this sensitization, a

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light touch to the siphon alone produced a strong gill withdrawal response, and this sensitization
effect lasted for several days.
Fig.4: A stimulus tends to increase the response with
number of attempts under sensitization
Associative learning
Associative learning is any learning process in which a new response becomes associated with a
particular stimulus. In its broadest sense, the term has been used to describe virtually all
learning except simple habituation.
Classical conditioning
Classical conditioning is a Conditioned behaviors is the result of associative learning. In 1902, the
Russian physiologist, Ivan Pavlov, began his famous experiments on conditioning. Pavlov repeatedly
presented a dog with food following the ringing of a bell. When the bell sounded without the
presentation of food, the dog would still respond to the bell as if it were food. Pavlov collected the
dogs' saliva and found that the amount of saliva produced by bell ringing increased as the dogs were
more frequently exposed to the coupling of food presentation and bell ringing. The dog had learned
to associate the sound of the bell with food.
Pavlov called the food an unconditional stimulus, or UCS, because the dog's normal reaction would be
to salivate at the presentation of food. The bell he termed the conditional stimulus, or CS, because
response to the bell was conditional upon the association between the bell and food. For the same
reasons, salivation in response to food was labeled the unconditional response, or UCR, while
salivation in response to the bell was called the conditional response, or CR. Conditioning the dog to
salivate at the sound of the bell occurred as a result of a contingency between the UCS and the CS.
Pavlov's experiment was an example of positive conditioning. It is also possible to negatively
condition an animal by using an unpleasant UCS.

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Fig. 5: Classical conditioning of Ivan Pavlov
Operant conditioning
Operant conditioning is a Conditioned behaviors is the result of associative learning. In classical
conditioning, the animal receives no benefit from associating the CS with the UCS. However, in
operant conditioning, an unassociated behavior becomes associated with a reward. B.F. Skinner
designed an apparatus called a "Skinner box" to test the interaction between UCS and CS. A rat was
placed inside the Skinner box; if the rat pressed down a lever inside the box then the box would
release a food pellet. Soon, the rat pressed the lever far more often than he would just by chance.
Most likely, the first time the rat pressed the lever it was by chance. But with each instance of lever
pressing, the operant is reinforced by reward with food. The rat learns that pressing the lever is
associated with food, and so he will increasingly press it. Almost any operant and reward system can
be used effectively.
Fig. 6: Skinner box
Imprinting

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Imprinting describes any kind of phase-sensitive learning (i.e., learning that occurs at a particular
age or life stage) during which an animal learns the characteristics of some stimulus, which is
therefore said to be "imprinted" onto the subject. The imprinting must occur in a critical or
sensitive period of life.
Fig. 7: Filial imprinting enables young ones to recognize theirs
mother immediately after hatching out of their eggs
Gooselings following
Lorenz
The best known form of imprinting is filial imprinting, in which a young animal learns the
characteristics of its parent. Lorenz observed that the young of waterfowl such
as geese spontaneously followed their mothers from almost the first day after they were hatched.
This means hatchling perceive their mother immediately after hatching out of the eggs. Conrad
Lorenz demonstrated how incubator-hatched geese would imprint on the first suitable moving
stimulus they saw within what he called a critical period of about 36 hours shortly after hatching.
The first thing a certain brood of baby geese saw when they hatched was Lorenz. The baby geese had
imprinted on Lorenz himself as their mother. The filial is irreversible once something has been
imprinted upon. The hatchling geese imprinted on Conrad Lorenz was permanent and nothing could
de-imprint them.
Sexual imprinting, which occurs at a later stage of development, is the process by which a young
animal learns the characteristics of a desirable mate. Sexual imprinting is a general imprinting; it is
not specific to individuals, only species typical characteristics. If a male were to imprint specifically on
his sister, or vice versa, inbreeding would result, which reduces a population's fitness. The more
general system of sexual imprinting allows young to learn to recognize potential mates without
inbreeding. Females learn to recognize what an appropriate mate should look like from their siblings
or neighbors. There are many examples of offspring raised by foster parents of a different species
preferring to mate with the foster species over its own species. For example, male zebra finches
appear to prefer mates with the appearance of the female bird that rears them, rather than mates of

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their own type (Immelmann, 1972). Golden eagle males show sexual imprinting with other species
females.
Fig. 8: Zebra finch Golden eagle
Reverse sexual imprinting has also observed: when two individuals live in close domestic proximity
during their early years, both are desensitized to later sexual attraction. This phenomenon, known as
the Westermarck effect, has probably evolved to suppress inbreeding.
Cognitive learning
Humans, other primates, and some non-primate animals are capable of sophisticated learning that
does not fit under the heading of classical or operant conditioning. The German scientist Wolfgang
Köhler found that the chimps were capable of abstract thought and could think their way through
possible solutions to a puzzle, envisioning the result of a solution even before they carried it out.
Fig. 9: Wolfgang Kohler (1913-17) conducted experiments on chimpanzees of using tools for obtaining
food rewards.
For example, in one experiment, Köhler hung a banana in the chimpanzees' cage, too high for them
to reach. Several boxes were also placed randomly on the floor. Faced with this dilemma, some of the
chimps—after a few false starts and some frustration—stacked the boxes one on top of the other,

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climbed on top of them, and got the banana. This behavior suggests they could visualize the result of
stacking the boxes before they actually carried out the action.
Associative learning occurs in highly intelligent animals, like birds and mammals. It depends on the
information gathered through keen observation and also involves the process of ‘dual code’
mechanism either through linguistic code or mental image code.
2.2 Types of Animal behavior
Defensive behavior in octopus.
The Octopus has an amazing body design. They are able to defend themselves in a variety of ways.
They seem to be able to adapt to their various environmental changes. With that, they end up finding
creative ways to protect themselves. That is why they generally leave the larger species alone. Now
Australian scientists discovered a new side to octopus intelligence, showing that some octopuses
carry coconuts to later use as shelter which may indicate tool use. Cephalopods (octopuses, squid and
cuttlefish) are widely regarded as the most intelligent of the invertebrates. Not only do they have
their dramatic and complex colour and shape change abilities, recent observations show unexpected
behavioural flexibility and the capacity to physically manipulate their environment.
Fig.10: Octopus carrying coconut shells Hiding in the shells
Defensive tool use in octopuses is an interesting phenomenon from the perspective of invertebrate
cognition. Tool use is a cognitive behavior normally associated with advanced primates like
chimpanzees, or crows and parrots, who are also famous for their high intelligence. But octopuses
boast impressive intelligence levels too, and are routinely documented exhibiting impressively clever
behaviors.
Predatory behavior in Lion.
With relatively small hearts and lungs lions are not fast runners; a maximum speed of 60kph, nor do
they have the stamina to keep this pace for more than a 100 – 200m. As such, lions rely on stalking
their prey and seldom charge until they are within 30m, unless the prey is facing away and cannot
see the charge.

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Lions usually stalk their prey, although ambush behaviour has been observed mainly during daylight
when stalking prey is more difficult. Generally, if a lion misses its target on the first run it usually
abandons the chase. Females are significantly more likely to stalk anything.
Lions hunting in pairs and groups have a success rate of c. 30%. Lions hunting singly by daylight
have a success rate of 17 - 19%. Most successful hunts are on dark nights in dense cover against a
single prey animal.
One reason for lions’ relatively low hunting success rate is that lions do not take into account wind
direction when hunting
Cooperative hunting brings a greater probability of success in lion hunts.
The group fans out, with certain lions stalking at a greater distance to encircle the prey. The
encircling lions launch the attack, seemingly to drive the prey towards the others who ambush from
their cover position.
Fig.11: Predation in Lion: Stalking, ambush and attack
Schooling in fishes:
Aggregation in fish occurs for various purposes like mating, breeding, feeding, migration, defense etc.
there are two types of fish aggregation viz. shoaling and schooling.
a. Shoaling
Any group of fish that are swimming closely together and follows a general direction are said to be
shoaling. Shoaling fish can relate to each other in a loose way, with each fish swimming and foraging
somewhat independently, they are nonetheless aware of the other members and swimming, so as to
remains close to the other fish in the group. Shoaling groups can include fish of dissimilar sizes and

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can including mixed-species subgroups. Individual fish in a shoal may do as it pleases. Each fish may
just be scouring around for food or resting nearby. Shoaling fish are very common in both freshwater
& marine habitat.
b. Schooling
Schooling fish are usually of the same species and the same age/size. Fish schools move with the
individual members precisely spaced from each other. Schooling fish will not only swim closely
together, they will form a very tight formation and will swim in a much synchronized manner. The
schools can perform very complicated manoeuvres (a movement or series of moves requiring skill
and care) such as changing of directions and turning as a whole. Fish schools are one of the best
examples of aggregation in animals. Schools are groups of fish that act as a single unit, and are
characterized by a streamlined structure and uniform behavior for the purposes of avoiding
predators and finding food. Schooling fish are commonly found in the marine habitat.
Individuals join schools for selfish reasons; therefore, in order for schooling to improve fitness, the
schools must offer benefits greater than the costs of increased visibility to predators, increased
competition, and energetic instability.
Fig.12: Shoal of fishes School of fish
Aggressive behavior in Gorilla:
Although gorillas typically aren't aggressive, they do exhibit territorial behavior by standing upright
on their bottom two legs and pounding their chests in order to intimidate whatever threat they have
been given. These gestures, however, are more for show and aren't usually violent. These instances
can come about when two silverbacks of different troops meet, when two males are fighting over a
female that they want to mate with, or when a younger male is challenging the silverback for
dominance of the troop. However, in stable troops these acts of violence and aggression are very
rare.

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Fig.13: Silverback (alpha male) Female Aggression between two silverbacks
Courtship display in Great Crested Grebe:
The grebe’s courtship ritual was first described in detail by the ornithologist Julian Huxley in 1912.
The courtship starts in the month of February in the initial phase of breeding. Both sexes grow black
and orange facial ruffs and black ear-tufts known as tippets, which they use in a special ceremony to
establish their bonds in the breeding season.
In the middle of the new reed bed pool, one bird approaches the other underwater to emerge
suddenly. Mutual head shaking follows – each bird mimicking the other. Facing each other, the
grebes flick their heads from side to side or slide towards each other, low in the water like alligators.
One bird's head goes up, shakes its head, lowers it and then waits. The second bird does the
same. This happens several times. They then swim apart and then swim together. One bird ruffles
its head and shakes it as before. The second bird does the same.
Fig.14: Great Crested Grebe Weed dance a final acceptance
The climax of their ritual is the weed dance in which both birds, holding tufts of water weeds in
their bills, paddle furiously to maintain an upright position chest to chest; an unforgettable sight and
an impressive display of stamina.

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Territorial behavior in tiger:
Home range is a space required for regular activities of an individual e.g. prowling, foraging, water
body, mating etc.
Territory is protected strictly for the requirement of basic niche like food, water and shelter.
Territories are regularly marked by urination and defecation.
Fig.15: Marking and active protection of territory by tiger
A tiger’s home range is larger than the territory. The size of home range can vary a lot depending on
the type of habitat. Male tiger’s home ranges were found around 267–294 km2
and female’s ranges
ere around 70–84 km2
. The size of territory not only depends on the population of the tiger but also
on the abundance of prey. A tigress will need a 202
kilometers territory. A male tiger requires a
larger territory, from about 60 to 1002
kilometers.
Fig.16:

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Both male and female tiger tend to live solitary and maintain the territory for the requirement of
space and prey therefore its a place where they satisfy all their needs. Females are more tolerant to
other females.
Occasionally two males live in a single territory. In such case one of them is dominant and other
submissive.
During mating season, the disputes are at their most violent between territorial males. Such
disputes may cause the death of one of the aggressors. However, such an event is rare.
Social behavior in Elephants:
Elephants form deep family bonds and live in tight matriarchal family groups of related females
called a herd.
An African elephant family group can average 8-10 individuals, where as an Asian elephant unit tends
to be smaller, averaging 4-8 individuals
Matriarchs are generally the oldest and largest adult female member of a family which , lead
elephant families. Matriarchs express their dominance in both competitive and cooperative
situations.
Fig.17: Herding in matriarchal herding, bull and bachelors
These female-led herds usually consist of adult daughters, their calves, and a number of juvenile and
adolescent male and female offspring. Female herd members are usually related, but occasionally
non-related individuals join to form families
Male, or bull elephants in the wild, leave or are driven out of the family group as they approach
sexual maturity.
Males spend as much as 95% of their lives solitary or in loose association with other bulls called as
bachelor group.

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They communicate through chemosensory (scent) and infrasonic (low-frequency calls) channels
with other elephants in their area.
In early years of adulthood, the young bulls spend time learning the capabilities of other bulls in their
area and establish a social hierarchy and status.
As they age and grow larger, thus able to compete effectively for breeding opportunities, the bulls
appear to spend their time eating and seeking out females.
Elephant bull nature is competitive, rather than affiliative.
2.3 Animal Communication:
 Definition, components
 Types of communication-Visual, Sound, Tactile, Chemical. 
Fig.18: Types of communication in animals
2.3.1: Definition of communication:
Animal communication is the transfer of information from one or a group of animals (sender or
senders) to one or more other animals (receiver or receivers) that affect the current or future
behaviour of the receivers. Communication is usually between animals of a single species, but it can
also happen between animals of different species.
Animals exhibit communication for several reasons e.g. contest, mating, territorial, ownership,
alarm, food-related, establish dominance, defending territory, coordinate group behavior, and care
for young.
2.3.2: Components of Communication:
 Sender and receiver: The organism sending the communication signal is called the sender, and
the one adjusting his behavior in response is called the receiver.
 Channels: Visual, Auditory, Olfactory, Tactile, Seismic, Thermal, and Electric.
 Medium: Air, space, water, light, sound, smell or any other medium.

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 Modes of signals or stimuli: Cues/ gaze/ movements/gestures and postures/symbols/
language/representations such as procedural, explicit and declarative. The first category
comprises cues, which are instances where the sender trait has not evolved for communication
purposes, but receivers are still processing information from them. When an act by an organism
triggers a response in another organism is called as communication signal. One example of a cue
would be a squirrel that uses information about the position of a branch of a tree to guide his
behavior. The tree probably has no advantage in “signaling” its position, but the squirrel can still
use visual information coming from the tree to guide its climbing behavior. Metacommunication
is all the nonverbal cues like tone of voice, body language, gestures, facial expression, etc. that
carry meaning that either enhance or disallow what we say in words.
 Response: Response depends on the perception of the receiver. There are certain factors involved
on the perception of the receiver such as whether the receiver is belonging to same species,
earlier experience of animal about the signal, distortion due to the available environment etc.
 Outcome: The contingent response of the receiver will give the outcome. The intensity and the
variation in the outcome is contingent on the environment, species, age, etc.
Discrete Signals:
Discrete signal has a fixed set of possible values. Discrete signals are the ones which indicate yes or
no; positive or negative; presence or absence of any signal. E.g. gorse keeps its ears straight and
directing indicates its interest or curiosity to object in front. Ears bent backwards indicates displease.
Hostile or an angry horse will frequently put her ears back and show the whites of her eyes.
Fig. 19: Erect ears: normal and happy Ears pointed forward: expression
of friendliness
Ears backwards: Hostile

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Analogue Signals:
Analog signals are continuous in both time and value. In animals the continuous signals like
openness of mouth in horse will indicate the amount of intensity of the signal with which it is paired.
If the ears of horse is straight and mouth is opened slightly depicts that the horse is happy to some
extent. If the is opened wide then horse is extremely happy. Similar is the condition with the hostile
mood of the horse.
Friendly-Mouth closed: Normal Mouth open slightly: Slightly
happy
Mouth open wide: Very
happy
Hostile-Mouth open slightly: little
Uncomfortable
Mouth open medium: Threat Mouth open wide: Extreme
Threat
Fig.20: Degree of openness of mouth indicates the intensity of discrete expression
2.3.2: Types of communication
Visual Communication:
Visual communication involves signals that can be seen. Examples of these signals include gestures,
facial expressions, body postures, and coloration.
 Movements: Various movements of body or parts of body are of common use in animals to send
a signal to the counterpart. For example, peacock dance, great crested grebe dance, dogs wagging
tail and flapping of ears in elephants.
Fig.21: Movements used in communication by animals

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 Gestures and posture: Gesture and posture are widely used visual signals. For instance,
chimpanzees communicate a threat by raising their arms, slapping the ground, or staring directly
at another chimpanzee. Gestures and postures are commonly used in mating rituals and may
place other signals—such as bright coloring—on display. Following are some classic examples of
gesture and posture.
Facial expressions are also used to convey information in some species. For instance, what is
known as the fear grin—shown on the face of the young chimpanzee below—signals submission.
This expression is used by young chimpanzees when approaching a dominant male in their troop
to indicate they accept the male's dominance. Recently gaze is one of the aspects fetching more
attention from scientists, world over. Social animals coordinate their communication by
monitoring of each other's head and eye orientation. Such behaviour has long been recognized as
an important component of communication during human development.
Posrures in cats Facial expressions in Chimpanzee
Dominance
Fig. 22: Gesture-Posrure and facial expressions inanimals

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 Colourations: Mimicry and various colour patterns and colour changes on the body. Changes in
coloration also serve as visual signals. For instance, in some species of monkeys, the skin around
a female’s reproductive organs becomes brightly colored when the female is in the fertile stage of
her reproductive cycle. An organism's general coloration—rather than a change in color—may also
act as a visual signal. For instance, the bright coloration of some toxic species, such as the poison
dart frog, acts as a do-not-eat warning signal to predators. Colour patterns are used to
communicate different signals to the counterparts, such as warning, mating, camouflaging,
threatening etc. mimicry is a high level of colour pattern in animals mend to deceive enemy or
predators.
 Supernormal stimuli
A supernormal stimulus or superstimulus is an exaggerated version of a stimulus that elicits a
response more strongly than the stimulus for which it is evolved. Nikolaas Tinbergen, a Nobel
Prize winning ethologist, is the father of the term supernormal stimuli. Some animals use
oversize or over highlighted body parts to attract the mates, e.g. Fiddler crab and beak of horn
bills and toucans. Lorenz once put a football-sized model egg by the nest of a bird. The bird tried
to retrieve it using the same action pattern it would use for a normal sized egg. If a normal egg
was placed alongside the giant one, the bird made fruitless attempts to retrieve the big egg while
neglecting its own normal-sized egg. Lorenz called the exaggerated sign stimulus
a supernormal stimulus. Supernormal sign stimuli are bigger or more intense than normal. They
elicit a larger-than-normal response from the animal. Dr. Barret seems to think that the link is
Monarch
Viceroy
Batesian Mimicry Colour changing in chamelion
Owl moth
Fig. 23: Cryptic Mimicry Cryptic mimicry

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closer then we believe, arguing that supernormal stimulation govern the behavior of humans as
powerfully as that of animals. It is demonstrated wearing lipstick on lips by female is a
supernormal stimulus for males.
Fig. 24: Supernormal stimuli chela in fiddler crab, beak of toucan and big size egg in herring gull
 Photo-communication
Communication by the production of light occurs commonly in vertebrates and invertebrates in the
oceans, particularly at depths (e.g. angler fish). Two well-known forms of land bioluminescence occur
in fireflies and glow worms. Other insects, insect larvae, annelids, arachnids and even species
of fungi possess bioluminescent abilities.
Fig. 25: Light communication in aquatic and terrestrial animals are used for communication
within and other species.
Sound (Auditory):
Auditory communication—communication based on sound—is widely used in the animals. Auditory
communication is particularly important in birds, who use sounds to convey warnings, attract mates,
defend territories, and coordinate group behaviors. Some birds also produce birdsong, vocalizations
that are relatively long and melodic and tend to be similar among the members of a species. Many
non-bird species also communicate using sound. Sound signals transmit efficiently over large
distances, around obstacles such as trees and foliage, and in dark environments. Nevertheless, sounds
of all frequencies become less intense as they radiate away from a source. Higher frequencies suffer

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additional attenuation owing to heat losses and scattering of the sounds. Since small animals can
produce only high frequencies (short wavelengths), their sound communication is often limited to
short distances. Furthermore, ambient sound is often greatest at low and high frequencies, making
intermediate frequencies the ones least likely to be obscured by the background.
Fig. 26: Infrasound communication in elephants and whales
Monkeys cry out a warning when a predator is near, giving the other members of the troop a chance
to escape. Vervet monkeys even have different calls to indicate different predators.
Bullfrogs croak to attract female frogs as mates. In some frog species, the sounds can be heard up to a
mile away!
Gibbons use calls to mark their territory, keeping potential competitors away. A paired male and
female, and even their offspring, may make the calls together.
Water, like air, can carry sound waves, and marine animals also use sound to communicate.
Dolphins, for instance, produce various noises—including whistles, chirps, and clicks—and arrange
them in complex patterns. The idea that this might represent a form of language is intriguing but
controversial.
Infrasonic communication (sound of below 20Hz) in Elephants and Whales: Elephants, which cannot
fly or climb, resort to sufficiently low frequencies that they can be detected several kilometres
away. Whales also produce low frequencies and move sufficiently far beneath the ocean surface
before vocalizing, which enables their signals to be heard hundreds of kilometres away (Fig. 26).

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Tactile (touch) communication:
Tactile signals are more limited in range than the other types of signals, as two organisms must be
right next to each other in order to touch. Still, these signals are an important part of the
communication repertoire of many species.
Tactile signals are fairly common in insects. For instance, a honeybee forager that's found a food
source will perform an intricate series of motions called a waggle dance to indicate the location of the
food. Since this dance is done in darkness inside the nest, the other bees interpret it largely through
touch. Foraging: Some ant species recruit fellow workers to new food finds by first tapping them
with their antennae and forelegs, then leading them to the food source while keeping physical
contact.
Fig. 27: Touch communication: Grooming Cuddling hugging and pecking
Tactile signals also play an important role in social relationships. For instance, in many primate
species, members of a group will groom one another—removing parasites and performing other
hygiene tasks. This largely tactile behavior reinforces cooperation and social bonds among group
members. Mating: Mammals often initiate mating by grooming, stroking or rubbing against each
other. Prolonged physical contact or huddling also serves social integration. Huddling promotes heat
exchange, particularly in penguins of Antarctica.
Chemical communication:
A pheromone is a secreted chemical signal used to trigger a response in another individual of the
same species. Pheromones are especially common among social insects, such as ants and bees.

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Pheromones may attract the opposite sex, raise an alarm, mark a food trail, or trigger other, more
complex behaviors.
Fig. 28: Chemical communication in animals
Pheromone trails laid down by ants to direct others in the colony to sources of food. When a food
source is rich, ants will deposit pheromone on both the outgoing and return legs of their trip,
building up the trail and attracting more ants. When the food source is about to run out, the ants will
stop adding pheromone on the way back, letting the trail fade out. Ants also use pheromones to
communicate their social status, or role, in the colony, and ants of different "castes" may respond
differently to the same pheromone signals./ A squashed ant will also release a burst of pheromones
that warns nearby ants of danger—and may incite them to swarm and sting. Dogs also communicate
using pheromones. They sniff each other to collect this chemical information, and many of the
chemicals are also released in their urine. By peeing on a bush or post, a dog leaves a mark of its
identity that can be read by other passing dogs and may stake its claim to nearby territory. Many wild
animals use pheromone for marking territory, identifying young ones, mates and strangers.
Thermal communication:
A number of different snakes have the ability to sense infrared (IR) thermal radiation, which allows
these reptiles to derive thermal images from the radiant heat emitted by predators or prey
at wavelengths between 5 and 30 μm. The accuracy of this sense is such that a blind rattlesnake can
target its strike to the vulnerable body parts of a prey animal.[25]
It was previously thought that the

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pit organs evolved primarily as prey detectors, but it is now believed that they may also be used to
control body temperature.
The facial pits enabling thermoregulation underwent parallel
evolution in pitvipers and some boas and pythons, having
evolved once in pitvipers and multiple times in boas and
pythons. The electrophysiology of the structure is similar
between lineages, but it differs in gross structure anatomy.
Most superficially, pitvipers possess one large pit organ on
either side of the head, between the eye and the nostril (loreal
pit), while boas and pythons have three or more
comparatively smaller pits lining the upper and sometimes
the lower lip, in or between the scales. Those of the pitvipers
are the more advanced, having a suspended sensory
membrane as opposed to a simple pit structure. Within the
family Viperidae, the pit organ is seen only in the subfamily Crotalinae, the pitvipers. Despite the
detection of IR radiation, the pits’ IR mechanism is dissimilar to photoreceptors; while
photoreceptors detect light via photochemical reactions, the protein in the facial pits of snakes is a
temperature sensitive ion channel. It senses infrared signals through a mechanism involving
warming of the pit organ, rather than chemical reaction to light. This is consistent with the thin pit
membrane, which allows incoming IR radiation to quickly and precisely warm a given ion channel
and trigger a nerve impulse, as well as vascularize the pit membrane to rapidly cool the ion channel
back to its original “resting” or “inactive” temperature
Common vampire bats (Desmodus rotundus) have specialized IR sensors in their nose-leaf. Vampire
bats are the only mammals that feed exclusively on blood. The IR sense enables Desmodus to
localize homeothermic animals such as cattle and horses within a range of about 10 to 15 cm.
This infrared perception may be used in detecting regions of maximal blood flow on targeted prey.
Seismic communication:
Seismic communication is the exchange of information using self-generated vibrational signals
transmitted via a substrate such as the soil, water, spider webs, plant stems, or a blade of grass. This
form of communication has several advantages, for example it can be sent regardless of light and
noise levels, and it usually has a short range and short persistence, which may reduce the danger of
detection by predators. The use of seismic communication is found in many taxa, including frogs,
kangaroo rats, mole rats, bees, nematode worms, and others. Tetrapods usually make seismic waves
by drumming on the ground with a body part, a signal that is sensed by the sacculus of the receiver.
The sacculus is an organ in the inner ear containing a membranous sac that is used for balance, but
Fig. 29: Pit vipers with heat sensory pits

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can also detect seismic waves in animals that use this form of communication. Vibrations may be
combined with other sorts of communication.
Fig. 30: Seismic communication is common in animals like Kangaroo rat and spiders
Olfactory communication:
Despite being the oldest method of communication, chemical communication is one of the least
understood forms due in part to the sheer abundance of chemicals in our environment and the
difficulty of detecting and measuring all the chemicals in a sample.[19]
The ability to detect chemicals
in the environment serves many functions, a crucial one being the detection of food, a function that
first arose in single-celled organisms (bacteria) living in the oceans during the early days of life on
Earth.[19]
As this function evolved, organisms began to differentiate between chemicals compounds
emanating from resources, conspecifics (same species; i.e., mates and kin), and heterospecifics
(different species; i.e., competitors and predators).[19]
For instance, a small minnow species may do
well to avoid habitat with a detectable concentration of chemical cue associated with a predator
species such as northern pike.[20]
Minnows with the ability to perceive the presence of predators
before they are close enough to be seen and then respond with adaptive behaviour (such as hiding)
are more likely to survive and reproduce. Scent marking is a common form of olfactory
communication in mammals.
Autocommunication:
Autocommunication is a type of communication in which the sender and receiver are the same
individual. The sender emits a signal that is altered by the environment and eventually is received by
the same individual. The altered signal provides information that can indicate food, predators or
conspecifics. Because the sender and receiver are the same animal, selection pressure maximizes
signal efficacy, i.e. the degree to which an emitted signal is correctly identified by a receiver despite
propagation distortion and noise. There are two types of autocommunication. The first is
active electrolocation found in the electric fish Gymnotiformes (knifefishes)
and Mormyridae (elephantfish) and also in the platypus (Ornithorhynchus anatinus). The second
type of autocommunication is echolocation, found in bats and Odontoceti.

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Electrolocation: Electrocommunication is a rare form of communication in animals. It is seen
primarily in aquatic animals, though some land mammals, notably the platypus and echidnas, sense
electric fields that might be used for communication.
Weakly electric fishes provide an example of electrocommunication, together with electrolocation.
These fish use an electric organ to generate an electric field, which is detected by electroreceptors.
Differences in the waveform and frequency of changes in the field convey information on species, sex,
and identity. These electric signals can be generated in response to hormones, circadian rhythms, and
interactions with other fish. Some predators, such as sharks and rays, are able to eavesdrop on these
electrogenic fish through passive electroreception.
Echolocation:
Echolocation is the use of
sound waves and echoes to
determine where objects are
in space. Echolocation, also
called bio-sonar, is the
biological sonar used by
several kinds of animals.
Echolocating animals emit
calls out to the environment
and listen to the echoes of
those calls that return from
various objects near them. They use these echoes to locate and identify the objects. Echolocation is
used for navigation and for foraging (or hunting) in various environments.
Echolocating animals include some mammals and a few birds; also in simpler form in other groups
such as shrews, one genus of megachiropteran bats (Rousettus) and two cave dwelling bird groups,
the so-called cave swiftlets.
Bats use echolocation to navigate and find food in the dark. To echolocate, bats send out sound
waves from their mouth or nose. When the sound waves hit an object they produce echoes.
Fig. 31: In echolocation a high frequency sound is used to locate the
distance and structure of the object.

Animal behaviour: Introduction to Ethology

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