Animal BehaviorAnimal Behavior

Social Interactions in Social Interactions in EcosystemsEcosystems

Animal Behavior

Observable coordinated responses

to stimuli

Originates with genes that direct the formation

of tissues and organs of the animal body

Instinctive BehaviorInstinctive Behavior

Performed Performed without having been learnedwithout having been learned

Usually triggered by simple sign stimuliUsually triggered by simple sign stimuli

Response is a stereotyped motor program, Response is a stereotyped motor program,

a fixed-action patterna fixed-action pattern

Learned BehaviorLearned Behavior

Responses are modified with Responses are modified with experienceexperience

Some categories of learned behaviorSome categories of learned behavior

ImprintingImprinting Spatial learning Insight Spatial learning Insight

learninglearning Habituation Habituation

Classical conditioningClassical conditioning

Operant conditioningOperant conditioning

ImprintingImprinting--Konrad Lorenz----Konrad Lorenz--

Time-dependent learningTime-dependent learning

Triggered by exposure to a sign Triggered by exposure to a sign

stimulus during a ‘sensitive period’stimulus during a ‘sensitive period’

Young geese imprint on a moving Young geese imprint on a moving

object and treat it as “mother”object and treat it as “mother”

Classical ConditioningIvan Pavlov 1920’s

An autonomic response becomes

associated with a novel stimulus

Salivation became associated with sound of

bell that accompanied feeding

Operant ConditioningOperant ConditioningB.F. Skinner 1930’sB.F. Skinner 1930’s

A A voluntary actionvoluntary action becomes becomes

associated with its consequencesassociated with its consequences

A toad may attempt to eat a wasp with a A toad may attempt to eat a wasp with a

black and gold pattern and be stungblack and gold pattern and be stung

Thereafter, the toad will be Thereafter, the toad will be conditioned to conditioned to

avoid eating similar insectsavoid eating similar insects

Fixed Action PatternNiko Tinbergen

• Highly stereotypic behavior• Once begun…must be completed• Initiates by some external sign (colors,

movements)…’the releaser’• Stickleback fish attack other males that

invade territory…recognize the ‘red belly’ (the releaser that initiates the attack)

Habituation An individual learns NOT to respond

to a stimulus that has neither good

nor bad consequences (they “get

used to” the stimulus)

Pigeons in cities learn that people are

no threat and do not flee from them

(they ignore the stimulus)

Spatial Learning andTerritoriality

Through experience with an environment, an

organism creates a mental map

Some blue jays remember the location of dozens

of places where they have stored food

Territoriality – Organism ‘defends’ an area by

agonistic (aggressive) behaviors.

Done for food, mate, rearing young

Insight Learning

• An animal solves a problem

without trial-and-error attempts at

a solution

• Captive chimpanzees show insight

learning when they solve a novel

problem, as when they stack boxes

to reach food that is out of reach

Bird Song: Bird Song: Instinct + LearningInstinct + Learning

Bird comes prewired to listen to Bird comes prewired to listen to

certain acoustical cues; instinctively certain acoustical cues; instinctively

pays attention to particular soundspays attention to particular sounds

Which dialect the bird sings depends Which dialect the bird sings depends

on what song it hears; it learns the on what song it hears; it learns the

details of the song from others details of the song from others

around it around it

Selection for Behavior

Some variation in behavior has a genetic

basis

Some behavior promotes reproductive

success (is adaptive)

Genes that encode adaptive behavior

will increase in population

Adaptive BehaviorAdaptive Behavior

Behavior that promotes propagation of an Behavior that promotes propagation of an

individual’s genesindividual’s genes

Its frequency will be maintained or Its frequency will be maintained or

increase in successive generationsincrease in successive generations

Selfish and Altruistic BehaviorSelfish and Altruistic Behavior

Selfish behaviorSelfish behavior promotes an promotes an

individual’s genes at the expense of individual’s genes at the expense of

othersothers

Altruistic behaviorAltruistic behavior helps others at the helps others at the

expense of the altruist; may be expense of the altruist; may be

adaptive under certain adaptive under certain

circumstancescircumstances

Selfish Ravens

Heinrich observed what appeared to be altruistic calling by ravens at carcasses

Further observation showed that the callers were behaving selfishly

Calls helped callers recruit others and to overwhelm owners of the territory where the food was located

Communication SignalsCommunication Signals

• Intraspecific signals will evolve only if they Intraspecific signals will evolve only if they

benefit both signaler and receiverbenefit both signaler and receiver

• Variety of signal modalitiesVariety of signal modalities

Pheromones (chemical signals)Pheromones (chemical signals)

Visual signalsVisual signals

Acoustical signalsAcoustical signals

Tactile SignalsTactile Signals

PheromonesPheromones

Chemical signals that diffuse through air Chemical signals that diffuse through air

or wateror water

May bring about behavioral change in May bring about behavioral change in

receiver or cause physiological change receiver or cause physiological change

(priming pheromones)(priming pheromones)

Acoustical SignalsAcoustical Signals

Sounds used in communicationSounds used in communication

Used to Used to attract mates, secure attract mates, secure

territory, warn off rivals territory, warn off rivals

May also be used to May also be used to communicate communicate

danger, keep groups togetherdanger, keep groups together

Visual Displays

Important in courtship and in

aggression

Baring of teeth by baboon

communicates threat

Play bow in wolves solicits play

behavior

Flashing of fireflies attracts mates

Tactile Display Signaler and receiver communicate by

touch Honeybee dance language

Ritualized DisplaysRitualized Displays

Common behavior patterns are Common behavior patterns are

exaggerated and simplified exaggerated and simplified

Body parts may be enhanced or colored in Body parts may be enhanced or colored in

way that enhances the displayway that enhances the display

Ritualization is often important in Ritualization is often important in courtshipcourtship

displaysdisplays

Sexual Selection

Reproductive success is measured in number

of offspring produced

Reproductive success can be enhanced by

increasing the number of matings or the

quality of mates

Male Reproductive Strategy

• Males produce many energetically

inexpensive sperm

• Males often provide no parental care

• Males maximize reproductive success

by mating with as many females as

possible

Female Reproductive StrategyFemale Reproductive Strategy

Females produce large, Females produce large, energetically energetically

expensive eggsexpensive eggs

Females often provide Females often provide parental careparental care

Females increase reproductive success by Females increase reproductive success by

increasing the quality of their matesincreasing the quality of their mates

Choosy Females

Female choice can dictate rules of

male competition and shape male

behavior

Selects for males that appeal to females

Male hangingflies offer nuptial gifts

Selfish Herd

A group held together by self-interest

Other members of the group form a living

shield against predators

Individuals may compete for the safest

spots; positions in the center of the group

Dominance HierarchyDominance Hierarchy

Some individuals accept subordinate Some individuals accept subordinate

status to others status to others (lower “pecking order”)(lower “pecking order”)

Dominant members have higher Dominant members have higher

reproductive success than subordinatesreproductive success than subordinates

Subordinates may do better over long Subordinates may do better over long

term than if they were on their own term than if they were on their own

Altruistic BehaviorAltruistic Behavior

Nonbreeding helpers are found in Nonbreeding helpers are found in

mammals, birds, and insectsmammals, birds, and insects

Altruists apparently Altruists apparently sacrifice their sacrifice their

reproductive success to help othersreproductive success to help others