19. Animal Behaviour: Innate vs Learned Concepts
Innate (Unlearned) Behaviour
Definition: behaviours present at birth, performed correctly the first time without prior experience.
Properties- Genetically programmed; minimally influenced by environment.
Often rigid, stereotyped, and difficult to modify.
Provide immediate survival value for very young or inexperienced animals.
Fixed Action Pattern (FAP)
Sequence of unvarying, stereotyped motor acts triggered by a specific sign stimulus (a.k.a. releaser).
Once initiated, the sequence runs to completion even if the stimulus is removed.
Examples- Mosquito lands, inserts proboscis, and draws blood automatically once host cues (heat, CO, odour) are detected.
Male three-spined stickleback attacks any fish showing a red belly. The red colour alone is sufficient to trigger the full attack sequence until no red is perceived.
Orientation Movements
Help an animal position itself favourably with respect to environmental stimuli.
Taxis
Directed, oriented movement toward (+) or away (–) from a stimulus.
Has a clear vector (directionality).
Types/Examples- Phototaxis: movement toward light in moths (+) or away from light in cockroaches (–).
Chemotaxis, geotaxis, rheotaxis, etc.
Kinesis
Undirected change in rate of movement or turning related to stimulus intensity, not direction.
Example: woodlouse (pill-bug) becomes more active in dry areas and less active in humid areas, increasing probability of eventually ending up in moisture without any oriented travel.
Communication Signals
Animals communicate through various sensory channels to coordinate behaviors like mating, foraging, and predator avoidance.
Chemical Signals (Pheromones)
Pheromones: volatile or non-volatile chemicals released into the environment to influence behaviour/physiology of conspecifics.
Insects lay pheromone trails to food sources in addition to performing dances (e.g. honeybee waggle dance).
Advantages: work at night, around obstacles; low energetic cost.
Visual Signals
Convey information through postures, colours, displays, or movements.
Often effective over short to medium distances and require presence of light.
Examples: Male peacock's elaborate tail display for courtship; firefly bioluminescence for mate attraction; aggression displays (e.g., baring teeth).
Auditory Signals
Transmitted as sounds (calls, songs, echolocation clicks).
Can travel over long distances, around obstacles, and be effective day or night.
Examples: Bird songs for territorial defense and mate attraction; alarm calls warning of predators; whale songs for long-distance communication.
Tactile Signals
Communicate through physical touch.
Effective over very short distances.
Examples: Primate grooming for social bonding; honeybee waggle dance (includes tactile components as other bees follow); touch in wolf packs to reinforce dominance or submission.
Learned Behaviour
A durable modification of behaviour based on experience.
Allows flexibility and adjustment to variable environments.
Habituation
Decreased responsiveness to a repeated, inconsequential stimulus.
Example: urban pigeons stop fleeing from constant pedestrian traffic.
Imprinting
Rapid, irreversible learning limited to a sensitive (critical) period early in life.
Functions in parent-offspring recognition, species identification, song acquisition, etc.
Classics- Lorenz’s graylag goslings followed the first moving object (him) after hatching.
Songbirds must hear adult song within a narrow window or they can never sing properly.
Spatial Learning & Cognitive Maps
Establishment of memory that reflects the environment’s spatial structure.
Example: digger wasp locates nest by learning landmarks surrounding the nest entrance; nest sits at cognitive ‘centre of landmarks’.
Associative Learning
Connecting one stimulus or behaviour with another.
Classical (Pavlovian) Conditioning
An arbitrary neutral stimulus becomes associated with a significant stimulus, eliciting a similar response.
Pavlov’s dog: bell (neutral) + food (US) → salivation (UR); eventually bell alone → salivation (CR).
Operant (Instrumental) Conditioning
Trial-and-error learning; behaviour is modified by its consequences (reward or punishment).
Skinner box: rat accidentally hits lever → food pellet (reinforcer); frequency of lever pressing increases.
Insight & Problem Solving
Ability to apply past experience to novel situations without trial-and-error.
Often shown in primates, corvids, octopuses.
Example: chimpanzee stacks boxes to reach suspended banana.
Social Learning
Learning by observing or imitating others; forms cultural transmission.
Young chimp watches elder crack nuts with stone and later reproduces technique.
Instinct (Colloquial Usage)
Often used synonymously with innate behaviour: seemingly spontaneous, adaptive actions without learning (e.g. freezing when sensing looming shadow of predator).
Genetic & Environmental Interactions
Behaviour is usually polygenic; single mutations can, however, have large pleiotropic effects ("master regulatory genes").
Cross-fostering or common-garden experiments disentangle heredity vs environment.
Biological Rhythms
Regular, periodic changes in biological processes or behaviors, often entrained by environmental cues (zeitgebers).
Circadian Rhythms
Approximately 24-hour cycles that regulate physiological processes and behaviors.
Governed by internal biological clocks, often synchronized by light-dark cycles.
Examples: sleep-wake cycles in humans, daily patterns of feeding and activity in animals (e.g., nocturnal vs. diurnal behavior), photosynthetic cycles in plants.
Circannual Rhythms
Approximately annual cycles that govern seasonal behaviors.
Often involved in preparation for environmental changes.
Examples: breeding cycles, migration patterns, hibernation, seasonal changes in coat colour in mammals.
Foraging Behaviour
Natural selection should favour strategies that maximise net energy gain per unit time while minimising risk and cost.
Optimal Foraging Model
Weighs energy content (benefit) against time, energy expenditure, and predation risk (cost).
Example decision: lion chooses young elephant vs. zebra based on capture probability, handling time, and injury risk.
Mating, Parental Care & Sexual Selection (Brief Overview)
Sexual selection shapes traits that increase mating success (bright plumage, elaborate songs, combat structures).
Male parental care unusual in mammals but common in fish (e.g. jawfish mouth-brooding, seahorse male pregnancy).
Social Behaviors
Interactions between individuals within a species, influencing survival and reproduction. These often involve complex communication and organization.
Social Organization
Group living enables cooperation but can also lead to competition for resources and mates.
Forms of social organization:
Dominance Hierarchies: Pecking orders that reduce aggression within groups.
Territoriality: Defense of a physical area, often for exclusive access to resources or mates.
Cooperation: Individuals work together for mutual benefit (e.g., cooperative hunting, shared parental care).
Altruism: Behavior that benefits another at a cost to oneself. This often evolves through kin selection.
Altruism & Inclusive Fitness
Altruism: behaviour that reduces actor’s direct fitness while increasing recipient’s fitness.
Evolutionary explanation: genes promoting altruism can spread if they enhance inclusive fitness (direct + indirect genetic contribution).
Hamilton’s Rule
A gene for altruism is favoured when where- = coefficient of relatedness between actor and recipient (probability of sharing an allele because of common descent).
= additional offspring (or equivalent fitness units) produced by recipient due to altruism.
= fitness cost to actor (lost offspring).
Typical values- Parent–offspring, full siblings:
Half-siblings:
First cousins:
Prediction: individuals are more likely to perform risky altruistic acts for close kin than for distant relatives or strangers.
Competition & Exam Tips (UKBC/USABO Focus)
Know terminology (FAP, taxis, kinesis, imprinting, habituation, associative learning, optimal foraging, Hamilton’s rule).
Distinguish classical vs operant conditioning (passive association vs active trial-and-error).
Remember critical periods for imprinting and song learning.
Apply optimal foraging and Hamilton’s rule quantitatively if simple numbers are provided.
Familiarise yourself with example organisms (stickleback, pill-bug, honeybee, digger wasp, Pavlov’s dog, Skinner box rat, chimpanzee nut-cracking).
Real-World & Ethical Considerations
Behavioural studies guide pest control (e.g. exploiting pheromones), conservation (releasing hand-reared animals with proper imprinting), and animal welfare (enrichment, reducing habituation to chronic stress).
Criticisms: laboratory studies (especially on female mammals) may not reflect natural conditions due to hormonal cycles, pregnancy risk, etc.
Further Resources
USABO “Biolympiad” Bio-link (community-curated biology topics and notes).
Classic ethology texts: Tinbergen, Lorenz, von Frisch.
Journals: Animal Behaviour, Behavioural Ecology, Proceedings of the Royal Society B.