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

Animal Behavior Mostly studied beginning in early 20 th century Pioneers Ivan Pavlov—association behaviors, conditioned reflex. Won Nobel Prize in 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

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

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?

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

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

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

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

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

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 weeks old After 14 weeks old, more fearful of new things

Learned Behaviors Imprinting Learning occurs at a particular stage in life Filial imprinting Lorenz Many birds will “imprint” on moving object in 1 st 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.

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

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

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

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

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

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

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

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

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)

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

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

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

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

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

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

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

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

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