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Animal
Behaviour
Behaviour
What an animal does
How it does it
Animals Response to the biotic
Environment
Responses of animals to other animals
can be intraspecific or interspecific
They can be further classed as
aggressive or co-operative behaviours
Intraspecific Aggressive Responses
•Agonistic behaviour is aggressive behaviour towards
another member of the same species involving threats,
submissions, chases and physical combat. Agonistic behaviour
is a contest to determine who gains access to a resource.
(Does not include predatory aggression for obtaining food)
•Conflicts between members of the same species are usually
resolved with ritualistic behaviour. This prevents serious
injury to the combatants.
•Fighting to the death is non-adaptive to most animals. Only
occurs when eliminating a stranger from another group.
•The more scarce the resource the more intense the fighting.
Aggressive behaviour
•Belligerent behaviour by an animal that threatens to harm or
kill another animal with which it is competing.
•Combat is more likely to be physical if it is essential to the
survival and reproductive success of the competitors.
•Natural selection favours a quick end to combat to prevent
the winner from becoming too injured, to be able to take
advantage of the resources won.
•Fighting between males for mates is common. Winner mates
with female and passes on genes for successful fighting.
Selection may cause males to become larger than females
(sexual dimorphism).
Territories
•A territory is an area defended against other members of
the same species.
•It provides food, water supplies, nesting areas, and refuges
from danger.
•Ownership of a territory is signalled by vocalisations, scent
marking, visual displays.
•Boundary marking warns against accidental intrusion by
others of its species.
•Another animal is only likely to attempt to dislodge the owner
of the territory if it has a chance of being successful.
•Territorial behaviour is reinforced by natural selection where
the benefits to the species outweigh the risks and the energy
costs of defending the territory.
•Territories help to regulate the population to a size that can
be supported by the available resources.
Lair or Nest
Territory
Home range
•Territorial behaviour varies widely. Most animals
have a definite home. The area the animal covers
regularly in search of food and mates is the home
range. This area is not defended.
•The part of the home range defended against
others of the same species is the territory.
•Aggressive behaviour is used to hold on territories.
•Adaptive Features of Territoriality
•Ensures enough space for each animal – if in short supply and
needed for breeding, keeps population down.
•By spreading out reduces the spread of disease and
parasites. Also harder for predators to find them.
•Most successful males hold best territories and so ensure
best genes are passed on to offspring.
•Once territories are established the resources have been
divided. The losers will spread out and look for food elsewhere
rather than go on fighting.
•In some species males without territories do not
attract mates and do not breed.
•Territories ensure enough food for the animals and
their families.
•Territories ensure a safe, protected nest or home
for the young or at least a place to breed in the
case of communal breeding grounds.
•Animal now has an area with which it can become
familiar, can learn where food, water and protection
from predators is located.
•Territorial behaviour is set. Defenders and
intruders know their roles.
Marking and Defending Territories
Vocalisations – e.g. birds singing on boundaries of their areas
at dawn and dusk
Scent – e.g. marking with urine (dogs and cats) or faeces
Scent glands – special glands produce chemo markers.
e.g.: on rump, between horns (deer), wrists (lemur), behind
ears (cats)
Physical gesturing – crabs wave claws at edge of territory
Hierarchies
•Many animals that live in social groups have a dominance or
social hierarchy
•It is established and maintained by agonistic behaviour.
•Once established it is maintained by ritualised displays unless
a new animal enters the group or a low ranking individual
challenges a higher ranking animal. Cuts down competition and
tension in the group.
•Body postures are common dominance signals
•Males and females may have separate dominance systems, in
monogamous systems female usually acquires mates status
because he defends her from threats and attack.
•An established hierarchy reduces the number of competitive
conflicts in which individuals may get injured or killed as each
animal knows its position.
•Selective advantage is that higher-ranking individuals leave
more offspring than lower ranked individuals , lower members
have a higher chance of mating than if they were outcast.
•Gender, age and size or fighting ability are factors affecting
dominance in a hierarchy.
•Position in a hierarchy is normally established early in life e.g.
puppies play fighting to assert dominance.
•Wolves – female dominated hierarchy. Alpha female
dominates the behaviour of those below her. Including which
females are allowed to mate. Helps control the number to be
fed when food is scarce and ensures survival of her own pups.
•Pukeko – both males and females have hierarchies in their
communal groups.
•Barn-yard hens – linear order of dominance based on pecking
order. Top bird pecks all, bird below pecks the bird below
them, etc, etc. Lowest bird pecks no one.
•Strongest animal is Alpha all subordinate to them. Get best
food and choice of mates.
•Dominance maintained by posture - make look bigger, standing
on hind legs, fluffing up fur, holding tail erect : threat
displays- slaps, bites : vocalisations – snarls
•Subordinate responds with appeasement gestures which
prevent the dominant animal from attacking.
•Subordinate displays are the opposite to dominance
behaviours. Include lowering head and eyes, make look smaller,
cringing, tail between legs, exposing vulnerable parts
Win-Loss Tables
•Used to show hierarchies
•Each interaction recorded with the winner and loser shown.
•Wins shown in columns and losses in rows.
•Diagonal is theoretical, monkey paired against itself.
Total
e.g.:
Intersection of column E with row I shows
H E I
R
H
0
E 5
5
I 4 8
2 14
16
R 2 5 8
Total
that E won 8 times over I.
Intersection of column I with row E shows
that never won against E.
When column I is paired with R, I wins 8 times.
Whilst R wins 2 times. This is rare, as once
dominance is established there are few
challenges by the lower animal.
It is most likely R is a younger animal that is
on the way up and is challenging I.
Intraspecific Co-operative Responses
Includes group formation, pair bond formation and parental
care.
Requires a form of communication:
can be visual, vocal, chemical or tactile
Group Formation – Advantages of group behaviour
•Hunting - work as a team to kill prey. E.g. wolves, lions,
wild, dogs.
•Defence – form defensive circles or post guards to watch
for danger whilst rest of group feeds. E.g. Himalayan yaks
(circles), baboons (guards).
•Protection – Dolphins protect mothers during birth process
and help carry baby to surface until it has learned to breathe.
Baboons, mother and young in safest position in the pack
(centre).
•Insect societies – organisms specialised to carry out
aspects of maintenance of nest or hive. Centred around a
queen who co-ordinates group with pheromones.
•Clumping – confuses predators, difficult to pick out
individuals. E.g. shoals of fish, flocks of birds
•Breeding – Many groups from for breeding purposes.
Safest breeding sites are in the centre of the group.
E.g. penguins, gannets, gulls
Disadvantages of group behaviour –
•Competition for resources- abiotic and biotic
•Spread of disease – closer contact of individuals
•Parasites – closer contact, less likely if were spread out
•Increased conflict – due to competition for resources
Courtship and Pair Bond Formation
•Animals tend to keep an individual distance from each other,
even those in groups. Invading another's space is a threat.
•Courtship behaviour often shows the conflicting tendencies
to attack and yet allow the closeness of mating.
•Sex is adaptive as it requires:
Co-operation
Temporary suppression of aggressive behaviour
A system of communication, and species recognition
•Mating is not a simple process. It is fundamental to the
survival of the species. Partners must make sure they are:
Of the same species
Both fertile
Both fully prepared to mate
•Usually the female who chooses the male, male must compete
for her. Two ways in which a male can gain an advantage over
another male
Fighting or ritualised combat
Compete indirectly in attracting females by special displays
and adornments
•Sexual competition has led to evolution of such
things as :
Antlers, brilliant breeding colours, feathers,
ornaments.
•These make the male more attractive to the
female. Male-Male dominance encounters often let
the female judge the ‘fitness’ of the males.
•Some rituals allow the potential male suitors to
size up the opposition without fighting.
e.g. red deer stags roar on their territory
boundaries to indicate how strong they are to other
males. Roaring continuously takes energy so
indicates they are in good condition.
Courtship
•Ensures the two animals are of the same species
•May be a sign to start nest building
•May trigger ovulation
•Aggression is reduced by dances, call, movements
of the body in ritualised sequences, release of
pheromones, or touching.
•This allows the pair bond to strengthen, so more
intimate behaviours can take place.
•A pair bond is a stable relationship between
animals of the opposite sex that ensures
cooperative behaviour in mating and rearing of the
young.
Types of Young
Atricial
Helpless at birth. The young are well protected
by the parents. Blackbird is a common example.
Prococial
Well advanced at birth. Little care from parents.
Pukeko is a good NZ example.
Parental Care
Survival species depends on the breeding population
producing adequate numbers to establish a new
generation.
Achieved in 2 possible strategies.
r strategy – produce many relatively unprepared young,
each with a low chance of survival.
•No parental care, no investment of effort or food.
•Large number of offspring produced. Chance of some
will survive.
•Strategy does not greatly affect health of current
generation.
Parental Care
k-strategy – produce a few, well prepared offspring
which have a high chance of individual survival.
•Parental care of eggs, and care of the offspring.
•Parents invest considerable effort and food reserves to
increase the probability of survival.
•Young have colours and behavioural patterns that reduce
aggression in parents.
•The health of the existing generation is risked to
increase the chance of survival of the next generation.
•The degree of parental care varies between species.
Reproductive Strategies
•Monogamy- only 1 breeding partner. Common strategy
when both parents are required to raise young.
> 90% birds are monogamous
•Polygyny – male may mate with many females, and have
many young. Maximises genes passed on. Invests no
parental care. Females raise young, or r strategy.
•Polygamy – dominant male may have a harem of females.
•Polyandry – mating of one female with more then one
male, while each male only mates with one female. Rare
<1% of birds. Male often raises the offspring
Polygynadry – promiscuity. No pair bonds, very little
parental care. Males and females mate with more than
one member of the opposite sex. E.g. pukekos
Synchronised spawning – species all spawn at same time.
Cooperative Breeding – mated pair builds a nest, females
lays eggs in it. Hatchling cared for by parents and other
members of the group.
Kin Selection – selection that favours genes that
promote altruistic behaviour towards those genetically
related.
Social Insects – one queen who reproduces, all others are
infertile and have set jobs.
Interspecific Aggressive Responses
Competition for food
•Occurs when resources become scarce. Leads to stress
and a reduction in population size, especially for the least
successful species. One population may even become
extinct.
•Gause’s Principle (competitive exclusion principle) – ‘no 2
species with identical ecological niches can co-exist for
long in the same place’.
•One species will die out, or move away, or the species
will differentiate their niches (often subtlety).
Predator – Prey
•Not truly an aggressive relationship.
•Predators can limit a population to a healthy
level.
•Most predators tend to catch the least welladapted animal, sick or old.
•Keeps the gene pool of the prey strong.
•The 2 species are dependent on each others
well-being.
Adaptations for getting food.
Predator strategies
•Pursuit strategies –
fast processing of information  bigger brains,
specialised appendages
hunting in swarms
hunting in teams
using tools
•Ambush strategies –
wait and let the prey come to them
sifting environment
dangling baits
webs and traps
lying in ambush
•Parasitising a prey -
Parasite-Host Relations
•Generally exist at expense of the host. Tend to be
density dependent. Greater population numbers increase
transfer rate.
•Ectoparasite – found on outside of host
•Endoparasite – found inside the host
•Parasitoids – Parasitic at only one part of the life cycle.
Tend to kill the host, e.g. parasitic wasps: larvae eat host
but pupate into a free living adult.
Defence Strategies Against Predators
Recognise Animals by three things:
•Silhouette – an be disguised by
-disruptive colouration – markings that hide body outline
-cryptic colouration – colouration matches background
•Its eye – can be disguised by
-eye disappear amongst stripes, splotches
-false eye in non-vital parts
•Its bulk – can be disguised by
-counter-shading
Defence Strategies Against Predators
Other defences are:
•Startle the predator - fluffing up body hair or feathers to look
big, flash a false eye
•Pretend to be inedible - look like a stick or faeces
•Mimicry- an organism’s close imitation of a model to which it is
unrelated:
Batesian mimicry – harmless or non-poisonous species
resemble one that is obnoxious or poisonous
e.g. viceroy butterfly looks like a monarch butterfly
(poisonous)
•Mullerian mimicry – involves several poisonous that all have
similar warning colouration.
•Aposematic Warning Colouration – an animal warns that its
either dangerous or poisonous by having bright colours,
especially stripes
More Defence Strategies
•Warning sounds (grunts, squeaks)
•firing chemicals (snakes, ants)
•curling up
•retreating (shelled animal)
•hiding (freezing)
•escape by numbers (shoals of fish, flocks of birds)
•pretending to be dead
•designated animal to keep watch (meercats, baboons).
Interspecific co-operative responses
•Mutualism – both animals benefit from a relationship
- wrasse and some shrimp cleaning larger fish. Cleaner
gets food, bigger fish have parasites removed.
- mixed herds grazing, one warns of danger all warned
- ants and aphids, ants get honeydew and aphids get
protection
•Commensalism – a relationship when one animal benefits and the
other is not harmed or benefited by the arrangement
-ramora and sharks, shark makes a kill and ramora gets
food
•Antibiosis relationship where one is harmed and the other is
indifferent
- human waste in rivers, humans unaffected, fish harmed
- fungi producing waste products the inhibit bacterial
growth