Chapter 49

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Chapter 49Animal BehaviorAnimal BehaviorEthologystudy of animal behavior as a branch of biology. Tends to look at animals in natural environment.Comparative psychologystudy of animal behavior as a branch of psychology. Tends to look at animals in experimental situations.Behavioral ecologystudy of the ecological and evolutionary basis for animal behaviorAnimal BehaviorMostly studied beginning in early 20th centuryPioneersIvan Pavlovassociation behaviors, conditioned reflex. Won Nobel Prize in 1904.Niko TinbergenIndividual & social behavior patternsKonrad LorenzInstinctive behavior, imprintingKarl von FrischCommunication & pheromones in beesTinbergen, Lorenz, von Frisch won Nobel Prize in 1973 for their behavioral workAdaptive SuccessBehaviors help promote individuals production of offspringGive benefit to survivalFood gatheringPredator protectionMate selectionYoung rearingResource useTerritory protection

Behavioral QuestionsFirst described by Niko TinbergenWhen analyzing behavior, ask the following questions:Functionhow does the behavior impact on the animal's chances of survival and reproduction?Causationwhat are the stimuli that elicit the response, and how has it been modified by recent learning?Developmenthow does the behavior change with age, and what early experiences are necessary for the behavior to be shown?Evolutionary historyhow does the behavior compare with similar behavior in related species, and how might it have arisen through the process of phylogeny?

Instinctive BehaviorsNervous system pre-wired before birth/hatchingBehaviors do not need trainingGarter snakes & slug preferenceCoastal snakes eat slugsInland snakes ignore slugsHybrids intermediateGarter snakes & strikingCaptive-born snakes will strike at model with bird eyes

Instinctive BehaviorsFruit flies & mating geneMales must perform behavior or females wont mateGene can be turned of in males and turned on in femalesHormonal influencesvoles & matingFemales with high oxytocin levels (due to mating or injections) mate for lifeFemales with oxytocin blocked do not bond

Instinctive BehaviorsFixed action patternBehavior or sequence of behaviorsInstinctualFollowed to completion once startedNot always completely fixed, can be modifiedFirst described by Tinbergen & LorenzSign stimulusoutside stimulus that triggers FAPGraylag gooseWill roll a displaced egg back into nestWill roll ANY egg-like object back into nest Many mating displaysChick beggingParent landing at nestRed spot on beak

Learned BehaviorsEnvironment & experiences influence gene expression (behavioral)BirdsongInstinctual behaviorVariations, dialects exist in different habitatsBirds learn pattern in first few weeks of life

Learned BehaviorsMacaquesImo Learned to wash potatoes in seaLearned to wash wheat by throwing into seaOthers performed same behaviors by observingChimpanzeestool useVaries by regionSticks for gathering termitesRocks for opening nuts

Learned BehaviorsMany behaviors related to timingErik Eriksons 8 stages of developmentAs child ages, behaviors develop at different timesBirth-18 mo, basic trust6-12 yr, self-confidence or inadequacy among peersDogsAccept new experiences between 4-12 weeks oldAfter 14 weeks old, more fearful of new things

Learned BehaviorsImprintingLearning occurs at a particular stage in lifeFilial imprintingLorenzMany birds will imprint on moving object in 1st 36 hours of life.Consider that object their parentCan be useful in rehabilitationSexual imprintingLearn characteristics of desirable mateZebra finches prefer mates that appear like bird that reared them.

Learned BehaviorsAssociationStimulus linked to another stimulus that may not be related to the firstPavlovRing bell before feeding dogsDogs salivatedEventually salivated just with bellFish moving to surface when hand seenDog excited when seeing leash

CommunicationInstinctive & learnedSent & received among a speciesSignalssingle cue, meant to change receivers behaviorDisplayspattern of behavior, social signal

Communication SignalsPheromonesSignalinginduce receiver to respond fastHoneybee alarm callsSexual attractionPriminginduce physiological changeUrine of male mice can induce & enhance estrus of females

Communication SignalsAcousticalSoundsAttract females (birds, frogs)Alarms (prairie dogs)Territory possession (wolves, birds, kangaroo rats)VisualVisible changes in behavior or appearanceLaid-back vs. erect earsErect hairsColor changes

Communication DisplaysMore complicated than a signal, sequence or pattern of behaviorsCourtshipWell developed in birds, mammalsDanceOften elaborate patterns, ritualized stepsNormal movements or structures exaggerated or frozen

Communication DisplaysThreatSignaler prepared to attack receiverSignaler benefits if rival backs down without fightReceiver benefits by avoiding serious injury or deathProtectionTerritoryMates

Communication DisplaysInformationMany insectsVon Frisch & beesWhen return to hive, move in specific patternsPattern tells others distance & direction of food

Sexual SelectionCompetition for reproductionUsually female choosing among malesDifferent than courtship displays, but may include themNuptial giftmale brings female food item, female chooses male with best one Many insects, flies, spiders

Sexual SelectionLekMating arenaMales gather in single area & display or competeFemale moves among them & choosesGenerally compete for center positionDeer, some fish, many birdsPhysical competition between malesExtravagant physical displays (peacocks)

Parental CareCare of young requires time & energyCould use this for survival & more reproductionYoung more likely to survive w/ careCost of care usually outweighed by survival improvementNumber of offspring decreases as length of parental care increasesThe more involved the male is with care, the more monogamy seen

Parental CareNo CareNeither parent gives any interest after laying eggsMost invertebrates, most vertebrates except birds & mammalsPaternal CareFather cares for youngRare (seahorses, midwife toads, some birds & mammals)Maternal CareMother cares for youngMost common if any parental careBi-Parental CareBoth parents care for youngMost birds, some fish, many mammalsParental CareInfanticideKilling of youngMost often by unrelated malesEliminates rival males genesMay stimulate female to go into estrus, enabling him to breedRats, lions, many other animals (especially mammals)Some females spontaneously abort when new male takes over

Social BehaviorIn most habitats, costs outweigh benefitsCompetition for limited resourcesLarge social groups attract more predatorsCrowded conditions encourage spread of parasites & diseaseAnimals of the group more likely to be injured, killed, or exploited by others

Social BehaviorCooperative predator avoidanceSome species have sentinels that give alarmsMeerkats, prairie dogs, vervet monkeysSome join in counterattackSmaller birds mob predatory birdsAnts, bees mob when nest disturbedSome have more effective defenseSawfly caterpillarsSelfish Herdprotect collective self-interest, protect young

Social BehaviorCooperative huntingLarger prey than could be killed individuallyPrey that could otherwise fight or outrun predatorTwo or more individualsMany animals of all kindsWolves, lions, wild dogs, starlings, orcas, tuna, army antsReproductive advantageEasier access to matesCommunal care of youngAnts, bees, rats, primatesCost of care distributed among adults

Social BehaviorDominance HierarchiesUneven distribution of resources Dominant gain more resourcesSubordinates might not survive on ownSubordinates might live long enough to reproduce

Social BehaviorEusocial animalsTrue socialhighest level of hierarchy divisionDistinct social classes/castesDivision of laborBreeding female dominates, others dont breedRemain together for many generationsInsects (wasps, bees, ants, termites)Mole rats

Social BehaviorEusocial animals (cont.)Altruistic behaviorhelps others, harms or gives no benefit to performerAustralian honeypot ant workerliving containerSoldier termitebombards, nozzle headGenes not passed, but can be favored if closest relative will benefit2 siblings as genetically identical as parent & offspring