Science of Animal Behavior Science of Animal Behavior
Ethology Ethology n n Study of animal behavior as a science had its Study of animal behavior as a science had its roots in the 1872 work of Charles Darwin roots in the 1872 work of Charles Darwin
n n Ethology Ethology n n Science of animal behavior in its natural habitat Science of animal behavior in its natural habitat
n n A central theme of ethology A central theme of ethology n n Behavioral traits can be isolated and measured Behavioral traits can be isolated and measured and they have evolutionary histories and they have evolutionary histories
n n Sociobiology Sociobiology n n Ethological study of social behavior and Ethological study of social behavior and originated with E.O. Wilson’s 1975 book originated with E.O. Wilson’s 1975 book
n n Social behavior is reciprocal communication Social behavior is reciprocal communication of a cooperative nature that permits a group of a cooperative nature that permits a group of organisms of the same species to become of organisms of the same species to become organized and is represented by four organized and is represented by four “pinnacles” “pinnacles” n n Colonial invertebrates, such as the Portuguese Colonial invertebrates, such as the Portuguese man man of of war, are tightly knit composites of war, are tightly knit composites of interdependent individual organisms interdependent individual organisms
n n Social insects such as ants, bees and termites Social insects such as ants, bees and termites have developed sophisticated systems of have developed sophisticated systems of communication communication
n n Dolphins, elephants and some primates, have Dolphins, elephants and some primates, have highly developed social systems highly developed social systems
n n Humans have a unique social behavior Humans have a unique social behavior
n n Behavioral ecology Behavioral ecology n n Focuses on individual behavior that maximizes Focuses on individual behavior that maximizes
reproductive and evolutionary success and reproductive and evolutionary success and studies mate choice, foraging, parental studies mate choice, foraging, parental investment, etc. investment, etc.
n n Much of the work by comparative Much of the work by comparative psychologists and ethologists can be psychologists and ethologists can be found under the discipline of behavioral found under the discipline of behavioral ecology ecology
Science of Animal Behavior Science of Animal Behavior
Describing Behavior: Principles of Classical Ethology Describing Behavior: Principles of Classical Ethology
Early Work Early Work n n Konrad Konrad Lorenz and Lorenz and Niko Niko Tinbergen Tinbergen described the basic concepts in described the basic concepts in animal behavior animal behavior
n n What appears to be rational retrieval What appears to be rational retrieval of an egg by a goose can be a of an egg by a goose can be a “fixed “fixed pattern” behavior pattern” behavior
n n Such predictable sequences are Such predictable sequences are called called stereotypical behaviors stereotypical behaviors
n n Lorenz labeled any stimulus that Lorenz labeled any stimulus that triggered a certain innate behavior triggered a certain innate behavior as a as a releaser releaser
n n If the animal responded to If the animal responded to just one specific aspect of just one specific aspect of the releaser, this was the releaser, this was designated a designated a sign stimulus sign stimulus n n Alarm call of an adult bird Alarm call of an adult bird may release a freeze may release a freeze response in a chick response in a chick
n n Tinbergen’s male Tinbergen’s male stickleback fish became stickleback fish became aggressive at the sign of aggressive at the sign of another male’s red flank another male’s red flank
Describing Behavior: Principles of Classical Ethology Describing Behavior: Principles of Classical Ethology
Innate Behavior Innate Behavior n n Invariable, predictable, stereotyped behaviors Invariable, predictable, stereotyped behaviors are inherited or are inherited or innate innate
n n Instinctive behaviors are dependent on Instinctive behaviors are dependent on interactions between an organism and its interactions between an organism and its environment environment
n n The behavior is independent of learning The behavior is independent of learning n n Programmed behavior Programmed behavior
n n Important for survival, especially when animals Important for survival, especially when animals receive little or no parental care receive little or no parental care
n n More complex animals with longer lives have More complex animals with longer lives have more time for social interactions and learning more time for social interactions and learning
n n Genetics of Behavior Genetics of Behavior n n Hereditary transmission of most innate behaviors Hereditary transmission of most innate behaviors is complex with many interacting genes is complex with many interacting genes
n n However, some behavioral differences within However, some behavioral differences within species show simple Mendelian transmission species show simple Mendelian transmission n n Honeybee Hygiene Honeybee Hygiene
n n Susceptible to a bacterial disease called Susceptible to a bacterial disease called American foulbrood American foulbrood
n n Removal of dead larvae from hive reduces Removal of dead larvae from hive reduces chance of spreading infection chance of spreading infection
n n “Hygienic” bees, uncap cells and remove “Hygienic” bees, uncap cells and remove rotten larvae rotten larvae
n n Two components of the behavior: Two components of the behavior: removal of cell caps and removal of larvae removal of cell caps and removal of larvae
n n A A backcross backcross with hygienic strains produced with hygienic strains produced
n n ¼ ¼ (U/U R/R) (U/U R/R) uncapped cells and uncapped cells and removed infected larvae removed infected larvae
n n ¼ ¼ (u/u R/r) (u/u R/r) uncapped cells only uncapped cells only n n ¼ ¼ (U/u r/r) (U/u r/r) did not uncap cells but did not uncap cells but removed larvae if another bee uncapped removed larvae if another bee uncapped cells cells
n n ¼ ¼ (U/u R/r) (U/u R/r) did not perform either part of did not perform either part of cleaning behavior cleaning behavior
n n Most inherited behaviors Most inherited behaviors do not show simple do not show simple segregation, but show an intermediate behavior segregation, but show an intermediate behavior n n Cross Cross breeding of lovebirds that carried nest breeding of lovebirds that carried nest material either in the beak or in the feathers material either in the beak or in the feathers produced hybrids that exhibited a confused produced hybrids that exhibited a confused carrying behavior carrying behavior
Learning and the Diversity of Behavior Learning and the Diversity of Behavior n n Learning: Modification of behavior Learning: Modification of behavior through experience through experience n n When the siphon of the marine snail, When the siphon of the marine snail, Aplysia Aplysia, , is prodded is prodded n n Snail withdraws its gills for protection Snail withdraws its gills for protection
n n If repeatedly prodded If repeatedly prodded n n It soon ignores the stimulus, a behavior It soon ignores the stimulus, a behavior modification called modification called habituation habituation
n n If a noxious stimulus is added to the If a noxious stimulus is added to the prodding prodding n n It is sensitized and rapidly withdraws its It is sensitized and rapidly withdraws its gills gills
n n These behaviors have been traced to These behaviors have been traced to nervous pathways, connecting nervous pathways, connecting sensory neurons to motor neurons sensory neurons to motor neurons that control the withdrawal muscles that control the withdrawal muscles
n n Repeated stimulations Repeated stimulations diminished release of diminished release of neurotransmitters neurotransmitters from sensory neurons from sensory neurons
n n Sensory neurons continued to fire, but with less Sensory neurons continued to fire, but with less neurotransmitter the system was less responsive neurotransmitter the system was less responsive
n n Sensitization involved action of a facilitating Sensitization involved action of a facilitating neuron that was stimulated by the noxious agent neuron that was stimulated by the noxious agent and increased the amount of transmitter released and increased the amount of transmitter released by the siphon sensory neurons by the siphon sensory neurons
n n More More complex kinds of learning complex kinds of learning may involve may involve formation of new neural pathways and formation of new neural pathways and connections as well as changes in existing connections as well as changes in existing circuits circuits
n n Imprinting Imprinting n n Imposes a stable behavior in a young animal Imposes a stable behavior in a young animal by exposure to particular stimuli during a by exposure to particular stimuli during a critical period in development critical period in development
n n A newly hatched or duckling follows its A newly hatched or duckling follows its mother mother n n If isolated, it follows the first large object it sees If isolated, it follows the first large object it sees
n n Konrad Lorenz hand Konrad Lorenz hand reared goslings and they reared goslings and they imprinted on him imprinted on him
n n There is only a brief sensitive period when There is only a brief sensitive period when imprinting can occur imprinting can occur n n The bond then lasts for life The bond then lasts for life
Learning and the Diversity of Behavior Learning and the Diversity of Behavior
n n Bird Songs Learned During a “Critical Bird Songs Learned During a “Critical Window” Window” n n Songbirds demonstrate robust sex differences in Songbirds demonstrate robust sex differences in many aspects of behavior many aspects of behavior
n n Songs of sparrows are important territorial calls Songs of sparrows are important territorial calls and rely partially on learning and rely partially on learning
n n If a baby bird is reared in isolation, it sings a If a baby bird is reared in isolation, it sings a rudimentary song rudimentary song
n n The sparrow must hear a normal bird song in a The sparrow must hear a normal bird song in a critical period 10 critical period 10– –50 days after hatching 50 days after hatching
n n The young sparrow does not learn the songs of The young sparrow does not learn the songs of other species of birds during this time other species of birds during this time
Learning and the Diversity of Behavior Learning and the Diversity of Behavior
n n Any response of one animal to another Any response of one animal to another animal animal of of the same species is a the same species is a social behavior social behavior
n n Two rival males fighting for possession of a female is Two rival males fighting for possession of a female is a a social interaction social interaction
n n Moths swarming around a light, or trout in a cold Moths swarming around a light, or trout in a cold portion of a stream are not exhibiting social behaviors portion of a stream are not exhibiting social behaviors n n Simply individuals responding to an environmental cue Simply individuals responding to an environmental cue
n n Social aggregations depend upon signals from the Social aggregations depend upon signals from the animals themselves animals themselves
n n Among some animals, breeding may be the only adult Among some animals, breeding may be the only adult social behavior social behavior
n n Other animals form strong monogamous Other animals form strong monogamous relationships for life relationships for life
n n Mother mammals and birds often form social bonds Mother mammals and birds often form social bonds with their young until they are fledged or weaned with their young until they are fledged or weaned
Selective Consequences of Sociality Selective Consequences of Sociality n n Social aggregations provide both passive and active Social aggregations provide both passive and active defense defense n n Organisms are safer in a group than they are alone Organisms are safer in a group than they are alone
n n In a breeding colony of gulls, an alarm call brings In a breeding colony of gulls, an alarm call brings many to attack the predator en masse many to attack the predator en masse
n n Prairie dogs live in a loose group and benefit from Prairie dogs live in a loose group and benefit from the extra eyes, ears and noses of others for warning the extra eyes, ears and noses of others for warning
n n The more animals there are in a group, the less likely The more animals there are in a group, the less likely an individual within the group will be eaten an individual within the group will be eaten
n n Sociality brings together males and females Sociality brings together males and females and synchronizes reproductive behavior and synchronizes reproductive behavior
n n In colonial birds, the sounds and displays In colonial birds, the sounds and displays trigger pre trigger pre reproduction endocrine changes in reproduction endocrine changes in the birds the birds
n n Living in close quarters, a bird colony Living in close quarters, a bird colony conspires to defend young and increase conspires to defend young and increase survival survival
n n Social organization also benefits in Social organization also benefits in cooperation in hunting for food, huddling for cooperation in hunting for food, huddling for mutual protection from severe weather, mutual protection from severe weather, opportunities for division of labor, and the opportunities for division of labor, and the potential for learning and transmitting useful potential for learning and transmitting useful information through the society information through the society
n n Transfer of innovative behaviors is illustrated Transfer of innovative behaviors is illustrated in the case of macaques on a Japanese in the case of macaques on a Japanese beach beach n n A female’s, Imo, acquisition of food A female’s, Imo, acquisition of food cleaning cleaning skills soon became common in the group skills soon became common in the group
n n Illustrates that the social setting provides Illustrates that the social setting provides opportunities for acquisition and sharing of opportunities for acquisition and sharing of complex learned behaviors complex learned behaviors
n n Disadvantages of social living Disadvantages of social living n n Camouflaged individuals survive predators by being Camouflaged individuals survive predators by being dispersed dispersed
n n Large predators need large amounts of food Large predators need large amounts of food n n The ecological situation determines if a solitary or social The ecological situation determines if a solitary or social strategy is better strategy is better
n n In socially coordinated behavior In socially coordinated behavior n n Individual adjusts its actions to presence of others to Individual adjusts its actions to presence of others to increase its own reproductive success directly increase its own reproductive success directly
n n In cooperative behavior In cooperative behavior n n Individual performs activities that benefit others because Individual performs activities that benefit others because such behavior ultimately benefits the individual’s genetic such behavior ultimately benefits the individual’s genetic contribution to future generations contribution to future generations
Antagonistic or Competitive Behavior Antagonistic or Competitive Behavior n n Aggression Aggression is an offensive physical action, is an offensive physical action, or threat, to force others to abandon or threat, to force others to abandon something something
n n Agonistic behaviors Agonistic behaviors are a broader category are a broader category including any activity related to fighting including any activity related to fighting
n n Animals reserve their dangerous weapons Animals reserve their dangerous weapons for securing prey and do not use them on for securing prey and do not use them on their own species their own species
n n Animal aggression within a species involves Animal aggression within a species involves symbolic or ritualized displays that avoid symbolic or ritualized displays that avoid injury or death injury or death
n n A A ritualized display ritualized display is a behavior that has is a behavior that has been modified through evolution to make it been modified through evolution to make it effective in serving a communicative effective in serving a communicative function function
n n A wide array of animal “fights” involve ritual A wide array of animal “fights” involve ritual jousts: fiddler crab claw battles, male jousts: fiddler crab claw battles, male rattlesnake dances, puffing fish, giraffe rattlesnake dances, puffing fish, giraffe “necking,” and bighorn sheep butting heads “necking,” and bighorn sheep butting heads
n n The loser of a ritualized battle often runs The loser of a ritualized battle often runs away or signals defeat by a subordination away or signals defeat by a subordination ritual ritual
n n The victor in such competition has access to The victor in such competition has access to the contested food, mates, or territory the contested food, mates, or territory
n n Schjelderup Schjelderup Ebbe first described the Ebbe first described the dominance hierarchy of chickens from the dominance hierarchy of chickens from the pecking order that the animal established in pecking order that the animal established in a barnyard a barnyard
n n Weaker members may die in times of food Weaker members may die in times of food shortage, etc. shortage, etc.
Territoriality Territoriality n n Territory Territory
n n Fixed area whose occupant exclude intruders of Fixed area whose occupant exclude intruders of the same species and sometimes other species the same species and sometimes other species
n n Territorial defense occurs in insects, Territorial defense occurs in insects, crustaceans, fishes, amphibians, lizards, crustaceans, fishes, amphibians, lizards, birds, and mammals birds, and mammals
n n Territoriality may be an alternative to Territoriality may be an alternative to dominance behavior dominance behavior
n n High cost of maintaining the territory High cost of maintaining the territory boundaries may outweigh the benefits boundaries may outweigh the benefits
n n Most energy may be expended in Most energy may be expended in establishing a territory establishing a territory n n Once established, it may be easy to defend Once established, it may be easy to defend
n n Male songbirds establish territories; the Male songbirds establish territories; the population remains stable as young assume population remains stable as young assume the parent’s role the parent’s role
n n Sea birds may establish a territory in a Sea birds may establish a territory in a colony that is barely the size of one nest site colony that is barely the size of one nest site
n n Mammals have home ranges rather than Mammals have home ranges rather than territories, and ranges may overlap territories, and ranges may overlap
n n A baboon troop may switch ranges to obtain A baboon troop may switch ranges to obtain better resources better resources
Mating Systems Mating Systems n n Behavioral ecologists classify mating Behavioral ecologists classify mating systems by the extent males and females systems by the extent males and females associate during mating associate during mating
n n Monogamy Monogamy is an association between one is an association between one male and one female at a time male and one female at a time
n n Polygamy Polygamy is a term that incorporates all male is a term that incorporates all male and female systems with more than one mate and female systems with more than one mate n n Polygyny Polygyny indicates that a male mates with more indicates that a male mates with more than one than one female female
n n Polyandry Polyandry indicates that a female mates with indicates that a female mates with more than one male more than one male
Altruism and Kin Selection Altruism and Kin Selection n n If animals behave selfishly to produce as many If animals behave selfishly to produce as many offspring as possible, then why do some offspring as possible, then why do some animals help others at risk to themselves? animals help others at risk to themselves?
n n Some cooperative behavior may be explained Some cooperative behavior may be explained easily easily
n n Other forms of cooperative behaviors seem to Other forms of cooperative behaviors seem to require additional explanation require additional explanation
n n Until the mid Until the mid 1960s, it was difficult to explain 1960s, it was difficult to explain altruistic behaviors altruistic behaviors
n n Mathematical game theory Mathematical game theory is now used to is now used to study behaviors to determine if they are study behaviors to determine if they are evolutionarily stable strategies or ESSs. evolutionarily stable strategies or ESSs.
n n An ESS is expected to persist over long An ESS is expected to persist over long periods of evolutionary time periods of evolutionary time
n n Kin Selection Kin Selection n n In 1964, William Hamilton proposed a theory of In 1964, William Hamilton proposed a theory of kin kin selection selection
n n Fitness is not just measured by an animal’s own Fitness is not just measured by an animal’s own offspring, but the increase or decrease in genes offspring, but the increase or decrease in genes shared in the gene pool shared in the gene pool
n n Alleles are shared closely with parents and Alleles are shared closely with parents and siblings siblings
n n Inclusive fitness Inclusive fitness is the relative number of an is the relative number of an individual’s alleles that are passed on to future individual’s alleles that are passed on to future generations from one’s own offspring or that of generations from one’s own offspring or that of related individuals related individuals
Animal Communication Animal Communication Signals Signals n n Through communication, one animal can influence the Through communication, one animal can influence the behavior of another behavior of another n n Animals are limited to communication using Animals are limited to communication using sounds, scents, sounds, scents, touch, pheromones and movement touch, pheromones and movement
n n In contrast to learned and highly variable human language, In contrast to learned and highly variable human language, animal communication is by signals animal communication is by signals
n n Each signal conveys one message Each signal conveys one message and cannot be rearranged to and cannot be rearranged to construct new kinds of information construct new kinds of information n n The song of a cricket signals the species, sex, location and social status of The song of a cricket signals the species, sex, location and social status of the sender the sender
n n The cricket cannot alter his song to provide additional The cricket cannot alter his song to provide additional information information
Communication Communication by Displays by Displays n n A A display display is a behavior that serves a is a behavior that serves a communicative communicative purpose purpose n n Moth pheromones, bee dances, gull alarm calls, and courtship Moth pheromones, bee dances, gull alarm calls, and courtship dances are all displays dances are all displays
