Animal Behavior

  1. Territoriality
    occurs when an animal lays claim to an area and defends it against other animals
  2. Dominance Hierarchy
    members of an aggressively organized group coexist with one another within one territory
  3. Simplest Dominance Hierarchy
  4. Visual, Chemical and Auditory signals are important?
    because of communication and recognition
  5. Special Properties of Dominance Hierarchies
    • Xenophobia
    • Strong Leadership Means Peace
    • The Will to Power
    • Nested Hierarchies
    • Social Inertia
  6. Why Xenophobia?
    • Disease
    • Competition for Mates
    • Competition for Resources
  7. Advantages to being Dominant
    • Get food
    • Get shelter
    • Get mates
    • Less stress
    • Grooming
  8. Consequences of being Subordinate
    • Less food
    • Reproduce less often
    • Poorer nesting sites and shelter
  9. why stay in a group if you are Subordinate?
    • Consequences of being subordinate
    • - emigration
    • - "sneak copulations"
    • - benefits of being in a group
  10. What qualities determine the dominance status of an individual?
    • - adults are dominant over juveniles
    • - bigger animals are usually dominant over smaller animals
    • - healthy animals are dominant over sick animals
    • - males are dominant over females
    • - animals are most dominant on their own territories
    • - accidents play a role
    • - intensity of status signals
  11. Intergroup Dominance
    • Slavery, Kignapping, Killing
    • - wolfs
  12. Consequences of Intergroup
  13. Territory
    • any defended area...contra Home Range
    • - recognized 2,300 years ago by Aristotle (2 Falcons will not occupy the same area..) (Formalized by Eliot Howard 1920)
  14. Home Range
    refers to all space used by an animal
  15. Functions of Territorial Defense:
    • - To control critical resources (e.g. for breeding): often advantageous to control somewhat more than the minimum amount
    • * male might be able to attract >1 female or a higher quality female (polygyny threshold model)
    • - To reduce predation (reduces chance of community becoming a popular hunting area)
    • - As a sexual advertisement
    • - To help with mate-guarding
    • - NOT to control popoulation size (Wynne-Edwards, Ardery)
  16. Economic Defendability
    • a resource attribute
    • - consider how large a territory ought to be staked out and maintained
  17. When does excluding others ('hogging') pay a higher return than sharing?
    Resource quality and spatial distribution ("patchiness")
  18. what happends when patch resources get a lot richer? What can we predict should happen to Territory Size?
    • The optimal size of territory to defend shrinks
    • - richer you get the more you can afford to relax (you no longer need to be desperate)
  19. Forming selfish herds
    • - animals move to position conspecifics between themselves and predators
    • - if predators take nearest animal, moving to center benefits individual
    • - result: form tight groups because each individual selfishy seeks middle
    • - forming groups does NOT imply cooperation
    • - each individual may be selfishly for its own benefit
  20. Confusing the Predator
    Several prey can flee in unpredictable directions
  21. Learning & Social Facilitation
    Experiments: John Krebs
    • - Birds search for a clumped source of food web more successful in groups of four than in pairs or singly
    • - different species can learn where food is from one another
  22. Adaptive Value of Being in a Group
    For Prey Species
    Passive: Thermoregulation, Kin related benefits, grooming, etc.
  23. Adaptive Value of Being in a Group
    For Predator Species
    • Coordinated Foraging
    • - makes more food availabe to be hunted
    • - reduces path overlap
    • - allows species to compete better for food with other competing species
    • - enables unsuccessful individuals to learn locations of new food resources from successful individuals in the group
    • - reduces energy costs or risks per individual or permits the taking of larger prey
  24. "Mixed Bird Parties"
    "Beating Hypothesis"
    Birds move through a field they flush out insects so all can eat or some leader species (large mammal) disturbs foliage causing insects to fly
  25. Hunting in Groups
    • reduces energy costs or allows animals to take larger prey
    • - weight of four social carnivores and weight of prey species they are able to kill
    • - hyena 100lbs/ 660 lbs
    • - lion 240 lbs/ 2000 lbs
    • - wolf 80 lbs/ 800 lbs
    • - hunting dog 35 lbs/ 550 lbs
  26. Classcial view of Communication
    ( mutually beneficial transfer)
    Image Upload 2
  27. Selfish model of Communication
    • Signal CAN be mutually beneficial, but should always, on average, benefit the signal sender
    • - corollary: it may benefit the receiver or it may exploit the receiver ruthlessly, or it may have utterly trivial value to the receiver
    • - viewed as coevolutionary 'arms race', in which all players play both roles (signal sender and receiver-- frequently)
  28. Each signal can be recognized as a transmission of energy which can be of many forms
    sound, light, touch, electrical, and chemical
  29. Choice of Energy Channel
    Vision-based Signals
    • Energy source = usually sun (occasionally bioluminescence)
    • Coding Variables
    • - Brightness (surface refelectivity)
    • - Color (uv of light NOT absorbed)
    • - spatial patternine of the above two
    • Properties
    • - short duration
    • - closed channel (receiver must have eyes open & be facing signaler)
    • - Long range
    • - Light rays don't bend; can be blocked
  30. Choice of Energy channel
    Acousitic-based signals
    • Energy source = Internal
    • Coding Variables
    • - pitch (= frequency = wavelength)
    • - loudness (energy level)
    • - temporal patterning is very important
    • Properties
    • - short-lived
    • - sound attenation
    • - channel continuously open
    • - can circumnavigate objects (esp. long-wave)
    • - localizable
  31. Choice of Energy channel
    Chemical Signals
    • Energy source = Pheromones = like hormones between individuals. Universal
    • Properties
    • - Channel open
    • - Amplification principle: tiny investment can elicit expensive response
    • - Enormous potential range (wind-borne)
    • - fantastic specificity
    • - flaw: achingly slow
  32. Hyena Social Behavior
    • - live in social groups called clans
    • - clan members defend a territory and hunt in groups
    • - femalse are dominant members of the clan ( clear dominance hierarchy)
  33. Major feature of social interaction in hyenas
    penis sniffing
  34. Pseudopenis
    • Females penis
    • - enlarged clitoris
  35. Pseudopenis is costly
    • - 10-20% of females die giving birth first time and 60% of first born pups die
    • - pseudopenis must provide big selective advantage to balance this
  36. Advantages of pseudopenis
    • - hormones increase aggression in females (increase social status, and access to food)
    • - sniffing appears to enhance cooperation among hyenas (communication)
    • - sniffing enable dominants to monitor hormonal status of other females
    • - dominant benefit: know if challenged
    • - subordinates benefit: allowed to remain in pack
  37. Evolutionary pathways
    complex traits evolve from less complex ones as a result of a long sequence of small developemental changes
  38. Evolution
    • - natural selection can only operate on the material available to it
    • - evolutionary intermediates must be improvements over what preceded them
    • - intermediate structures can have different functions to their current ones, but should be useful in some way
  39. Evolution of insect flight
    • - gill plates, retained in the adult, act as sails allows the insect to skim over the surfact of the water
    • - increaseing wing size would increase skimming speed
    • - beating wings would increase speed still further so adding musculature would be favored by selection
  40. Honest Signals
    - display signals to be expensive and difficult for smaller/ weaker individuals to imitate.
  41. Novel environment hypothesis
    (Dishonest signals)
    mistake made because environment has changed. response once adaptive.
  42. Exploitation hypothesis
    (Dishonest signals)
    • response adaptive on average, but sometimes expolited
    • - risk outweighed by benefits.
  43. What mechanisms favour honest communication?
    • 1. Common interest
    • 2. Handicap/cost
    • 3. Index of quality (uncheatable signals)
  44. Sexual Selection
    • a form of non-random mating
    • - selection that arises when individuals of one sex, usually males, gain an advantage over others of the same sex in obtaining mates
    • - targets loci that code for mate choice traits and changes allele frequencies
  45. Sexual Selection results in sexual dimorphism
    • - acts on males much more strongly than females
    • - females usually invest much mroe in their offsprint than do males
    • - females prefer males with certain characteristics
  46. Fundamental asymmetry of sex
    • - female fitness is limited by an ability to gain the resource required to produce egges and rear young
    • - male fitness is limited by the ability attract mates
  47. Two ways sexual selection can happen for males
    • - fighting between males
    • - attract females
  48. two forms of sexual selection
    • - intrasexual (fighting)
    • - intersexual (epigamic)- attract females
  49. Epigamic Selection
    females must show a sexual attraction for males that have certain secondary sexual characteristics (ornaments, behaviors, etc.)
  50. Sexual Dimorphism
    Male advantage and Female advatange
    • Males: possessing a character preferred by females is clear - he gets to mate more often
    • Females: mating with a male that has that character - character is heritable = more sons = more offspring
  51. Sexy Son Hypothesis
    • Female preference and male attractiveness evolve together
    • - Females that mate iwth males that do not have this character will produc less sexy sons and therefore their choice will be lost over time
  52. R.A. Fisher- Evolutionary Biologist
    • original character must have been some marker of some other characteristic that increases male fitness
    • - once that characteristic become linked to greater male fitness, ti become established simply for its attractive properties
  53. Polygamy
    more than one mate
  54. Polygyny
    male mates with more than one female
  55. Polyandry
    female mates with more than one male
  56. Resource Defense Polygyny
    • males gain access to female by controlling resource stahat are vital to females
    • - ex. bullfrogs ( with the best territories get the most mates)
  57. Female Defense Polygyny (Harems)
    • males gain access to females by directly defending them against rivals
    • - ex. elephant seals (most dominant gets the most mates)
  58. Male Dominance Polygyny
    Explosive Breeding & "Leks"
    • No male defense of females of resources
    • - males set up a dominance hierarchy and females choose them
    • - explosive breeders (short breeding period) (Cascades Frog)
    • - leks (communal display area) (Prairie Chicken)
  59. Male-male competition can be
    Traditional Combat or Indirect
  60. Nuptial feeding
    • Scorpionfly
    • - female eats while copulating with male
    • - copulation last as long as food lasts
  61. Do females always have a choice?
    • Scorpionfly
    • - secrete hard salivary mass/ pheromone induces females to mate
    • - disperse pheromone on deat insect after eatin dead insect female mates
    • - Forced copulation (rape) : male rushes female
  62. Blowfly attraction females
    • - attack and get insect to offer to potential female mate
    • - steal food from rival male to give to female
    • - turn into female, entice male to give you food and fly away and give it to female (transvestite blowflly strategy)
  63. Sexual Selection in monogamous species
    • Female coyness & mate choice
    • - males usually must display to females
    • - males ' salesmanship' (display, provide food, make a nest, etc.)
    • - females are 'coy'
  64. Female Choice Criteria
    • - correct species
    • - correct sex
    • - sexually mature
    • - good male genes; survivorship, reproductive ability, complimentarity of genes
    • - willingness in male to care for offspring
    • - ability to invest
    • - complimentarity of parental attributes
  65. Proximate Perspective
    • Focus on stimuli that trigger and support behavior
    • - genetic, physiological, neural, envrionmental
  66. FAP
    • Fixed action pattern
    • - unchangeable sequence of unlearned, innate behaviors
    • - once initiated, usually carried to completion
    • - sign stimulus
    • - external sensory stimulus
  67. Organization-Activation Hypothesis
    • Hormones and Behavior
    • - Organization: permanentmorph change, in early development, critical period
    • - Activation: during puberty, changes due to increase, androgens or estrogens
  68. Factors affecting physciological mechs
    • Physcial Environment ( Day length, temperature)
    • Social Environment (Social cues can cause hormonal changes)
  69. Behavioral changes due to development exposure
    • - exposure to androgen can masculinze females
    • masculine: aggressivenss, attacks, mounting and intromission, little parental behavior
    • feminine: non-aggressive, attractiveness to males, exhibit parental behavior
  70. Sensory system
    • part of the Nervous system
    • - samples the environment for information
  71. Motor system
    • part of the nervous system
    • - produces action
  72. Endocrine system
    • - organs produce class of proteins called hormones
    • - delivered passively via the circulatory system - relatively slowly
  73. Hormones have 2 different scales of operation
    organizational & activational effects
  74. Organizational effects
    • - occur very early
    • - influence a subset of neurons
    • - shape adult behavioral repertoire a permanent menu change
  75. Activational effects
    • - require immediate presence of key hormone for the sensitive neurons to function normally. to 'turn on'
    • - themporary (short term) menu change
  76. RIA
    • radioimmunoassay
    • - measures concentrations of hormones
  77. Challenge Hypothesis
    Basic predation = that (T) should be high when males are most aggressive with each other & vice versa
  78. True monogamy
    bonded for life with no replacement, even if mate dies
  79. Natural Selection vs. Sexual Selection
    • Natural: reproductive success, rivals = both sexes
    • Sexual: mating success, rivals = same-sex
  80. Limiting Sex
    • one sex becomes a restricted resource for the other (because it has higher costs associated with mating), access to it "limits" what the other sex can achieve
    • limiting sex: female
    • limited sex: male
  81. Parental Investment
    any effort toward one offspring that increases the change of that offsprins survival at the cost of the parents ability to invest in other offspring (Trivers)
  82. Externally-fertilized species
    can be observed
  83. Internally-fertilized species
    males probability of bieng genetically related to offspring is nearly always lower that of female
  84. Cruel Bind
    a focal male can either remian with his current mate and contribute to the raising of her young (STAY) or he can go off and seed a second mate (DESERT)
  85. Last Custody
    one parent departs before the other one has equivalent opportunity, it puts the partner in a cruel bind (depending on the brood's needs)
  86. Parental Care and Desertion
    • Most animals -- no parental care
    • 1. value for staying
    • - precocial young, altricial young
    • 2. value for deserting
    • - often hinges on availability of high-quality alternative mates
Card Set
Animal Behavior
Zoology 350/Biology 350