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Animal behaviorChapter 9

How do you define “behavior?”• An animal’s responses to internal & external

environmental cues• Behavior has adaptive value, just like other

traits, & can be influenced by natural selection– feeding behavior, parental care, singing songbirds

Two kinds of behaviors• Innate behaviors

– something born knowing; under strong genetic control (don’t need any environmental input to develop)

– performed virtually the same way each time & by all individuals of a species

– fixed action patterns (FAP): unchangeable responses to certain stimuli; once triggered, the sequence of behaviors is performed in its entirety

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Two kinds of behavior, cont.

• Learned behaviors– influenced by individual’s

environment– modifications of behavior

as a result of specific experiences

– enables animals to change behaviors in response to changing environmental conditions

– several types of learning

Types of learning

• Habituation• Imprinting• Spatial learning• Associative learning• Social learning• Problem solving

Habituation• Loss of response after

repeated exposure• Animal learns not to respond

to stimuli with little or no information

• Allows animal to ignore normal stimuli while remaining alert to out-of-the-ordinary stimuli

• Animals don’t waste energy on stimuli that are irrelevant to survival & reproduction

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Imprinting• Rapid learning that is

limited to a specific, sensitive time period in an animal’s life; memory retained throughout lifetime

• Mostly thought of in young, but also in new parents

• Imprinting has direct & immediate effects on survival & reproduction

Spatial learning

• When animals use area landmarks to find location of nest, food, mates, hazards

Associative learning

• The ability to associate one environmental feature with another

• Often trial & error learning: when an animal associates one of its ownbehaviors with a + or –effect

• Memory is key to associative learning

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Social learning

• Learning by observing the behaviors of others– alarm calls – learn basic

hunting skills or tool usage by mimicking mom

Problem solving

• The process of applying pastexperience to overcome obstacles in new situations

• Highly developed in some mammals, especially dolphins & primates, & some birds

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Survival & reproductive success based on several behaviors

• Foraging• Communication• Courtship rituals• Parental care• Social behaviors

Foraging/Feeding behavior• The process of searching for, &

capturing & eating food• Natural selection has refined

behaviors that enhance efficiency of feeding

• Foraging in groups reduces individual's risk of predation

• Hunting in groups improves success

Communication • The sending of information (signal) from one animal

to another• For defense, mate attraction, parental care• Auditory, visual, scents, touch • Generally, the more complicated the social structure

of a species, the more complex the signaling to sustain it

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Courtship rituals• Confirm individuals are

– same species– opposite sex– ready for mating (as

opposed to being a threat)• Vocalizations &/or

displays (often FAPs!)• Help with mate selection

– selection may also be based on physical looks, gifts up front, or control of resources

Parental care• Enhances reproductive

success• Amount of care invested

depends partially on relatedness; maternity known, paternity uncertain– offspring’s chance of survival

increases with paternal involvement

– paternity uncertainty can lead to mate guarding during female’s fertile period

• Depends partially on needs of offspring

Social behaviors

• Any interaction between two or more animals, usually of the same species– territorial behavior– agonistic behavior– altruism

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Territorial behavior• Animals defend an area

from others of the same species– size, resources & function

of territory vary by species• Territories established by

song, scents, patrolling• The benefits of increased

fitness outweigh the energy costs of defending territory

Agonistic behavior• Threats, rituals & sometimes

combat behaviors that determine which competitor gains access to a resource

• Usually posturing to avoid injury to either the winner or loser

• Typically inhibits further aggressive activity with loser giving way to winner in future chance encounters

• May maintain social groups in a dominance hierarchy: a ranking of individuals based on social interactions– higher ranking individuals are 1st to

food & mates which ensures reproductive success

Altruism• Acts of “kindness,”

behaviors that come at a cost to the individual performing them while benefiting a recipient– Cost & benefit are defined

in terms of contributions to an individual’s fitness

– Natural selection should not produce altruistic behavior

– On closer inspection, virtually all apparent acts of altruism are not truly altruistic

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Altruism result of . . . • Kin selection

– kindness towards close relatives who share many of the same genes

– the more closely related 2 individuals are, the more likely they are to act altruistically

– seems selfless, but “acting in the gene’s best interest”

• Reciprocal altruism– kindness towards non-relatives– “scratch my back & I’ll scratch yours”– common among humans, but rare

among other animal species