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Chapter 49

Chapter 49. Animal Behavior. Animal Behavior. Ethology —study of animal behavior as a branch of biology. Tends to look at animals in natural environment. Comparative psychology —study of animal behavior as a branch of psychology. Tends to look at animals in experimental situations.

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Chapter 49

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  1. Chapter 49 Animal Behavior

  2. Animal Behavior • Ethology—study of animal behavior as a branch of biology. Tends to look at animals in natural environment. • Comparative psychology—study of animal behavior as a branch of psychology. Tends to look at animals in experimental situations. • Behavioral ecology—study of the ecological and evolutionary basis for animal behavior

  3. Animal Behavior • Mostly studied beginning in early 20th century • Pioneers • Ivan Pavlov—association behaviors, conditioned reflex. Won Nobel Prize in 1904. • Niko Tinbergen—Individual & social behavior patterns • Konrad Lorenz—Instinctive behavior, imprinting • Karl von Frisch—Communication & pheromones in bees • Tinbergen, Lorenz, von Frisch won Nobel Prize in 1973 for their behavioral work

  4. Adaptive Success • Behaviors help promote individual’s production of offspring • Give benefit to survival • Food gathering • Predator protection • Mate selection • Young rearing • Resource use • Territory protection

  5. Behavioral Questions • First described by Niko Tinbergen • When analyzing behavior, ask the following questions: • Function—how does the behavior impact on the animal's chances of survival and reproduction? • Causation—what are the stimuli that elicit the response, and how has it been modified by recent learning? • Development—how does the behavior change with age, and what early experiences are necessary for the behavior to be shown? • Evolutionary history—how does the behavior compare with similar behavior in related species, and how might it have arisen through the process of phylogeny?

  6. Instinctive Behaviors • Nervous system “pre-wired” before birth/hatching • Behaviors do not need training • Garter snakes & slug preference • Coastal snakes eat slugs • Inland snakes ignore slugs • Hybrids intermediate • Garter snakes & striking • Captive-born snakes will strike at model with bird eyes

  7. Instinctive Behaviors • Fruit flies & mating gene • Males must perform behavior or females won’t mate • Gene can be turned of in males and turned on in females • Hormonal influences—voles & mating • Females with high oxytocin levels (due to mating or injections) mate for life • Females with oxytocin blocked do not bond

  8. Instinctive Behaviors • Fixed action pattern • Behavior or sequence of behaviors • Instinctual • Followed to completion once started • Not always completely “fixed”, can be modified • First described by Tinbergen & Lorenz • Sign stimulus—outside stimulus that triggers FAP • Graylag goose • Will roll a displaced egg back into nest • Will roll ANY egg-like object back into nest • Many mating displays • Chick begging • Parent landing at nest • Red spot on beak

  9. Learned Behaviors • Environment & experiences influence gene expression (behavioral) • Birdsong • Instinctual behavior • Variations, dialects exist in different habitats • Birds learn pattern in first few weeks of life

  10. Learned Behaviors • Macaques—Imo • Learned to wash potatoes in sea • Learned to wash wheat by throwing into sea • Others performed same behaviors by observing • Chimpanzees—tool use • Varies by region • Sticks for gathering termites • Rocks for opening nuts

  11. Learned Behaviors • Many behaviors related to timing • Erik Erikson’s 8 stages of development • As child ages, behaviors develop at different times • Birth-18 mo, basic trust • 6-12 yr, self-confidence or inadequacy among peers • Dogs • Accept new experiences between 4-12 weeks old • After 14 weeks old, more fearful of new things

  12. Learned Behaviors • Imprinting • Learning occurs at a particular stage in life • Filial imprinting • Lorenz • Many birds will “imprint” on moving object in 1st 36 hours of life. • Consider that object their parent • Can be useful in rehabilitation • Sexual imprinting • Learn characteristics of desirable mate • Zebra finches prefer mates that appear like bird that reared them.

  13. Learned Behaviors • Association • Stimulus linked to another stimulus that may not be related to the first • Pavlov • Ring bell before feeding dogs • Dogs salivated • Eventually salivated just with bell • Fish moving to surface when hand seen • Dog excited when seeing leash

  14. Communication • Instinctive & learned • Sent & received among a species • Signals—single cue, meant to change receiver’s behavior • Displays—pattern of behavior, social signal

  15. Communication Signals • Pheromones • Signaling—induce receiver to respond fast • Honeybee alarm calls • Sexual attraction • Priming—induce physiological change • Urine of male mice can induce & enhance estrus of females

  16. Communication Signals • Acoustical • Sounds • Attract females (birds, frogs) • Alarms (prairie dogs) • Territory possession (wolves, birds, kangaroo rats) • Visual • Visible changes in behavior or appearance • Laid-back vs. erect ears • Erect hairs • Color changes

  17. Communication Displays • More complicated than a signal, sequence or pattern of behaviors • Courtship • Well developed in birds, mammals • “Dance” • Often elaborate patterns, ritualized steps • Normal movements or structures exaggerated or frozen

  18. Communication Displays • Threat • Signaler prepared to attack receiver • Signaler benefits if rival backs down without fight • Receiver benefits by avoiding serious injury or death • Protection • Territory • Mates

  19. Communication Displays • Information • Many insects • Von Frisch & bees • When return to hive, move in specific patterns • Pattern tells others distance & direction of food

  20. Sexual Selection • Competition for reproduction • Usually female choosing among males • Different than courtship displays, but may include them • Nuptial gift—male brings female food item, female chooses male with best one • Many insects, flies, spiders

  21. Sexual Selection • Lek • Mating arena • Males gather in single area & display or compete • Female moves among them & chooses • Generally compete for center position • Deer, some fish, many birds • Physical competition between males • Extravagant physical displays (peacocks)

  22. Parental Care • Care of young requires time & energy • Could use this for survival & more reproduction • Young more likely to survive w/ care • Cost of care usually outweighed by survival improvement • Number of offspring decreases as length of parental care increases • The more involved the male is with care, the more monogamy seen

  23. Parental Care • No Care • Neither parent gives any interest after laying eggs • Most invertebrates, most vertebrates except birds & mammals • Paternal Care • Father cares for young • Rare (seahorses, midwife toads, some birds & mammals) • Maternal Care • Mother cares for young • Most common if any parental care • Bi-Parental Care • Both parents care for young • Most birds, some fish, many mammals

  24. Parental Care • Infanticide • Killing of young • Most often by unrelated males • Eliminates rival males’ genes • May stimulate female to go into estrus, enabling him to breed • Rats, lions, many other animals (especially mammals) • Some females spontaneously abort when new male takes over

  25. Social Behavior • In most habitats, costs outweigh benefits • Competition for limited resources • Large social groups attract more predators • Crowded conditions encourage spread of parasites & disease • Animals of the group more likely to be injured, killed, or exploited by others

  26. Social Behavior • Cooperative predator avoidance • Some species have sentinels that give alarms • Meerkats, prairie dogs, vervet monkeys • Some join in counterattack • Smaller birds mob predatory birds • Ants, bees mob when nest disturbed • Some have more effective defense • Sawfly caterpillars • “Selfish Herd”—protect collective self-interest, protect young

  27. Social Behavior • Cooperative hunting • Larger prey than could be killed individually • Prey that could otherwise fight or outrun predator • Two or more individuals • Many animals of all kinds • Wolves, lions, wild dogs, starlings, orcas, tuna, army ants • Reproductive advantage • Easier access to mates • Communal care of young • Ants, bees, rats, primates • Cost of care distributed among adults

  28. Social Behavior • Dominance Hierarchies • Uneven distribution of resources • Dominant gain more resources • Subordinates might not survive on own • Subordinates might live long enough to reproduce

  29. Social Behavior • Eusocial animals • “True social”—highest level of hierarchy division • Distinct social classes/castes • Division of labor • Breeding female dominates, others don’t breed • Remain together for many generations • Insects (wasps, bees, ants, termites) • Mole rats

  30. Social Behavior • Eusocial animals (cont.) • Altruistic behavior—helps others, harms or gives no benefit to performer • Australian honeypot ant worker—living container • Soldier termite—bombards, nozzle head • Genes not passed, but can be favored if closest relative will benefit • 2 siblings as genetically identical as parent & offspring

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