• Behavior: reaction of living things to stimuli (either from the physical environment or other living things)
    • Behaviors may be encoded in DNA or learned; group behaviors or individual
    • Behavior used to maintain homeostasis, find mates and nutrients
  • Proximate causation: how a behavior occurs or is modified
  • Ultimate causation: why a behavior occurs in the context of natural selection
    • Do it to increase fitness → find mates or survive

Kinds of Animal Behavior

  1. Instinct: behaviour that is innate/inherited (genetically controlled)
  • Ex: in mammals, care for offspring by the female parent is innate
  1. Fixed Action Patterns (FAPs) innate behaviors that follow a regular, fixed pattern
  • Initiated by specific stimulus and usually carried out to completion
    • Sign stimulus: external cue thats acts as a trigger for the behavior
  • Ex: if goose sees egg outside nest will roll back to nest → egg is stimulus → anything that looks like the egg will be treated same
  • Male stickleback fish defend territory against other males → red belly of a male is a stimulus for aggressive behaviour → any object with red initiates aggressive FAP
  1. Imprinting: an innate program for acquiring a specific behaviour only if have correct stimuli experienced during critical/sensitive period (limited time interval during life of an animal) → irreversible
  • Ex: geese goslings will accept any moving object as mothers, salmon imprint odors associated with birthplace so that they can return
  1. Learning
  • Learning: the modification of behavior as a result of specific experiences
  • Capacity for learning depends on nervous system organization established during development following instructions encoded in the genome
  1. Associative Learning (association) occurs when animal recognizes (learns) that two or more events are connected
  • One form called classical conditioning when an animal performs a behavior in response to substitute stimulus rather than normal stimulus
    • Ex: dogs salivate when presented with food → bell rung before giving food → dogs salivate in response to bell ringing alone; associated ringing of bell (substitute stimulus) with presentation of food (normal stimulus)
  1. Trial-and-error learning (operant conditioning): form of associative learning when an animal connects its own behavior with environmental response.
  • If response is desirable (positive reinforcement) animal will repeat behavior
  • If response is undesirable, animal will avoid behavior
  • Learning acquired by association can be forgotten or reversed if performed behavior does not result in expected response
    • Extinction: loss of acquired behavior
  1. Spatial learning: form of associative learning when an animal associates attributes of a location (landmarks) with reward it gains by going back there
  • Ex: wasps were able to associate nearby markers (pine cones) with location of nests; removed markers and couldn’t identify
  1. Habituation: learned behavior that allows animal to disregard meaningless stimuli
  • Sea anemones tentacles can ignore nonfood items after repeated attempts to grab food
  1. Observational learning: when animals copy behaviors of another animal
  • One monkey learned that could more easily clean potatoes in water and soon all monkeys did same
  1. Cognition and Problem Solving
  • Cognition: the process of knowing that involves awareness, reasoning, recollection, and judgment
  • Problem solving: the cognitive ability to overcome obstacles
  1. Insight: when an animal, exposed to new situation with no experience, performs behavior with desirable outcome
  • Ex: monkey will stack boxes to climb and access previously unreachable bananas
  1. Signaling behavior: response and communication between organisms that can change behavior and reproductive success
  • Organisms exchange info in response to internal and external signals
  • Cooperative behavior increases fitness of individuals and survival of the population


  • Some behaviors that appear learned may be innate but need maturation
    • Ex: birds appear to learn to fly by trial and error or observational learning but birds raised in isolation will fly on first try if are physically capable
  • Inherited behaviors and learning capabilities have evolved because increase individual fitness
    • Innate behaviors improve fitness by providing dependable mechanic for animal to respond to expected behavior
  • Associative learning allows individuals to benefit from unexpected events
    • Once form association can respond appropriately next time
  • Habituation allows them to ignore repetitive events which have learned (from experience) are inconsequential → can focus on more important events 
  • Observational learning and insight allows animals to learn new behaviors in response to unexpected events without receiving reinforcement
  • Game Theory: The fitness of a particular behavior is influenced by other behavioral phenotypes in a population


General Animal Behaviors

  • Animal always encountering different situations so respond to each in way that maximizes survival and reproductive success (fitness)

Survival responses: when encounters dangerous situation

  1. Fight-Flight response: animal encounters situation where must either fight or run
  • Response is triggered by stress and stimulates nervous system to produce adrenaline → prepares body by dilating blood vessels, increasing heart rate, and increasing release of sugar from liver into blood
  1. Avoidance response: when animal avoids encountering a stressful situation → associative learning bcuz recognizes that is stressful
  • Ex: avoid predator habitats, unfamiliar objects, scents, or sound
  1. Alarm response: triggered when animal detects threat so warns group
  • Ex: monkeys emit distinctive alarms for intruders, with special calls for snakes, birds and leopards


Foraging Behaviors:

  • Optimal foraging model: natural selection should favor a foraging behavior that maximizes the benefits (food eaten) & minimizes the costs (energy extended and risk) + behaviors that increases survival of populations
  1. Flower color and flower scent are signals that animals use to locate flowers (and that plants use to attract them)
  • Often vision and olfactory abilities of animals have coevolved with flower color and scents
    • Flowers provide animals protein (from pollen) and carbs (sugar in nectar) ←→ animals disperse pollen
      • Ex: bees attracted to blue or yellow flowers with sweet smell
  1. Fruit color: a signal that animal uses to locate fruit and know if are ripe/edible or toxic
  • Sometimes fruit color is warning that is poisonous; chemical signals provide cues that is edible
  • Food toxic to one animal may be nutritious for another and many animals have evolved metabolic pathways to detoxify plant materials
    • Ex: monarch butterflies use milkweeds to make themselves toxic
  1. Body scents: signals presence of predators
  • Ex: zebras increase vigilance when detect body odor
  1. Herds, flocks, and schools provide advantages when foraging
  • Concealment: most individuals hidden from view
  • Vigilance: more ppl watching
  • Defense: can shield or mob attack
  1. Packs: corner and attack large prey
  2. Search Images: look for abbreviated forms of of object to find favored or plentiful food

Social Behavior

May live in group or alone; always make contact to reproduce 

  1. Agonistic behavior (aggression and submission) originates from competition for food, mates, or territory
  2. Parental Care: innate behavior in response to producing offspring
  • Paternal behavior exists because it has been reinforced over generations by natural selection
  1. Dominance Hierarchies: indicate power and status among individuals in group → minimize fighting
  • Pecking order
  1. Territoriality: possession and defense of territory → ensure enough food and safety
  2. Eusocial (truly social) consists of members divided into castes  
  • One caste will forage, other will feed and care
  1. Altruistic behavior: seemingly unselfish behavior that appear to reduce fitness of an  individual
  • Often occurs when animal risks safety in the face of another to help another individual (of same species) rear its young
  • This behavior increases inclusive fitness: fitness of individual plus fitness of relatives (share % DNA)
    • Evolution of these behaviors occurs by kin selection: form of natural selection that increases inclusive fitness
    • Altruistic behavior can be maintained by evolution because furthers survival of population
  1. Ground squirrels give alarm calls that warns other squirrels of predators but risks own safety by revealing presence
  • These squirrels live in groups of closely related females so is example of kin selection
  1. Bees live in colonies made of queen and female daughters (worker bees) → only queen reproduces so fitness of workers is zero
  • Kin selection favors sterile workers in haplodiploid society because all sister bees share 75% genes and fitness of worker bees (by how much genes contributes to the next gen) is greater if it promotes production of sisters by nurturing queens rather than by themselves.
  • Reciprocal Altruism: exchange of aid between unrelated individuals
    • Do it bcuz think they will receive something in return in future

Animal Movement

  • Animals can respond to external stimuli by moving → allows them to seek food, shelter, safety, or mates
  1. Kinesis: undirected change in speed of an animal’s movement in response to stimulus
  • Animal slows down in favorable environment (stay longer) & speed up in unfavorable
    • Ex: animal will suddenly scurry about in response to light, touch, or air temp
  1. Taxis: directed movement in response to stimulus; either toward or away from stimulus
  • Phototaxis: movement in response to light; Chemotaxis: movement in response to chemicals
  • Ex: bacteria move toward oxygen or nutrients (positive chemotaxis) or away from taxis
  • Moths move toward light at night, sharks move toward when food odors reach them by diffusion or bulk flow (ocean current)
  1. Migration: long-distance, seasonal movement of animals; response to seasonal availability of food or degradation of environmental conditions
  • Ex: migrating birds use sun or stars (celestial cues) or magnetic field of earth