Introduction to Animal Behavior and Social Interactions

Animal behavior

The study of how and why animals interact with their environment and each other.

Behavioral ecology

A subfield of animal behavior that focuses on the evolutionary basis of behavior, examining how natural selection shapes behavior to enhance survival and reproduction.

Evolution

The change in the heritable characteristics of biological populations over successive generations.

Natural selection

The differential survival and reproduction of individuals due to differences in phenotype.

Fitness

The ability of an organism to survive and reproduce in its environment.

Adaptation

A trait that has evolved through natural selection to enhance an organism's fitness.

Phenotype

The observable characteristics of an organism, including physical traits, behaviors, and metabolic processes.

Behavioral Phenotype

The specific set of actions and reactions exhibited by an organism in response to internal and external stimuli.

Sign Stimulus (Releaser)

A specific cue that triggers a fixed action pattern.

Fixed Action Pattern

A predictable, stereotyped behavior sequence triggered by a sign stimulus.

Innate Releasing Mechanism

The neural mechanism that translates the detection of a sign stimulus into a fixed action pattern.

Instinct

A behavior that is fully functional the first time it is exhibited.

Supernormal Stimulus

An exaggerated stimulus that elicits a stronger response than the natural stimulus.

Ethogram

A catalog of discrete, species-typical behavior patterns.

Tinbergen's 4 Questions

A framework for understanding animal behavior by considering its proximate (mechanistic and developmental) and ultimate (functional and evolutionary) causes.

Proximate Causes

How a behavior works and how it develops.

Ultimate Causes

Why a behavior exists and how it evolved.

Events

Short-duration behaviors that can be approximated as points in time.

States

Long-duration behaviors, such as prolonged activities or postures.

Scan Sampling

Rapidly scanning a group of subjects and recording the behavior of each individual.

Focal Sampling

Focusing on one subject at a time and recording all the behaviors that individual displays.

The Scientific Method

A systematic approach to investigating phenomena and acquiring new knowledge, involving observation, hypothesis formulation, prediction, experimentation, and analysis.

Hypothesis

A testable explanation for an observation or phenomenon.

Prediction

A specific, measurable outcome that is expected if the hypothesis is supported.

Experiment

A controlled procedure designed to test a hypothesis.

Control Group

A group in an experiment that does not receive the experimental treatment and is used as a baseline for comparison.

Experimental Group

A group in an experiment that receives the experimental treatment.

Variable

Any factor that can change or be changed in an experiment.

Independent Variable

The variable that is manipulated by the researcher.

Dependent Variable

The variable that is measured to assess the effect of the independent variable.

Replication

Repeating an experiment multiple times to ensure that the results are consistent and reliable.

Statistical Significance

A measure of the probability that the results of an experiment are due to chance rather than a real effect of the independent variable.

Comparative Approach

A method of studying animal behavior by comparing the behavior of different species.

Independent Contrasts

A statistical method that accounts for phylogenetic relationships when comparing traits across species.

Continuous Traits

Traits that can take on any value within a certain range, such as body size or song complexity.

Discrete Traits

Traits that can only take on certain distinct values, such as mating system or diet.

Optimality Models

Models that predict the optimal behavior of an organism, given certain environmental constraints and assumptions.

Currency

The unit of measurement used to assess the costs and benefits of different behaviors.

Strategy Set

The set of alternative behaviors available to an organism.

Payoffs

The costs and benefits associated with each behavior in the strategy set.

Optimization Criterion

The rule used to determine the optimal behavior, such as maximizing or minimizing a particular currency.

Stochastic Payoffs

Payoffs that are probabilistic, meaning that the outcome of a behavior is not certain.

Central Place Foraging

A type of foraging where an animal travels from a central place (such as a nest) to a foraging patch and then returns to the central place with food.

Marginal Value Theorem

A theorem that predicts the optimal time an animal should spend in a foraging patch, given the travel time to the patch and the rate at which resources are depleted in the patch.

Optimal Foraging Theory

A framework for understanding how animals make decisions about what to eat and where to forage, based on the idea that natural selection favors individuals that maximize their energy intake per unit time.

Diet Choice Model

A model that predicts which prey items an animal should include in its diet, based on the profitability of each prey item and the encounter rate with each prey item.

Patch Choice Model

A model that predicts which foraging patches an animal should visit, based on the quality of each patch and the travel time between patches.

Central Place Foraging Model

A model that predicts how animals should forage when they must return to a central place, such as a nest, to deliver food or care for offspring.

Risk-Sensitive Foraging

A type of foraging where animals take into account the variability in food availability when making foraging decisions.

Red Queen Hypothesis

The hypothesis that organisms must constantly adapt and evolve to survive in the face of ongoing environmental change and co-evolution with other species.

Antagonistic Co-evolution

An evolutionary process where adaptations in one species lead to counter-adaptations in another, resulting in a continuous cycle of change.

Crypsis

The ability to avoid detection by blending in with the background.

Disruptive Coloration

A type of camouflage that breaks up the outline of an organism, making it harder to see.

Countershading

A type of camouflage where the upper surface of an organism is darker than its lower surface, making it harder to see against a background of varying light intensity.

Masquerade

When an organism resembles an inedible object, such as a twig or leaf.

Apostatic Selection

A type of natural selection that favors rare or unusual prey types, as predators develop search images for common prey.

Aposematism

The use of warning coloration to advertise unprofitability to predators.

Mullerian Mimicry

When two or more unpalatable species evolve to resemble each other.

Batesian Mimicry

When a palatable species evolves to resemble an unpalatable species.

Allocation Costs

The costs of investing resources in one trait that could have been invested in another.

Opportunity Costs

The costs of forgoing one activity in favor of another.

Brood Parasites

Organisms that lay their eggs in the nests of other species, which then raise the brood parasite's offspring.

Arms Race

An evolutionary process where adaptations in one species lead to counter-adaptations in another, resulting in a continuous cycle of change.

Mutually Beneficial

A behavior that benefits both the actor and the recipient.

Selfish

A behavior that benefits the actor at a cost to the recipient.

Altruism

A behavior that benefits the recipient at a cost to the actor.

Spite

A behavior that costs both the actor and the recipient.

Kin Selection

A type of natural selection that favors behaviors that benefit relatives, even at a cost to the actor.

Coefficient of Relatedness (r)

The probability that two individuals share a gene that is identical by descent.

Inclusive Fitness

The sum of an individual's direct fitness (through its own offspring) and indirect fitness (through the reproductive success of relatives).

Hamilton's Rule

A rule that predicts when altruism will evolve, based on the relatedness between the actor and recipient, and the costs and benefits of the behavior.

Kin Discrimination

The ability to recognize and differentiate between relatives and non-relatives.

Eusocial Insects

Insects that exhibit cooperative care of young, sterile castes, and overlapping generations.

Subsocial Route

A pathway to eusociality where offspring remain in their natal nest and help their mother rather than breeding independently.

Parasocial Route

A pathway to eusociality where multiple females come together to form a nest.

Monogamy Hypothesis

The hypothesis that strict lifetime monogamy is a key factor in the evolution of eusociality.

Haplodiploidy

A sex-determination system where males develop from unfertilized eggs and are haploid, while females develop from fertilized eggs and are diploid.

Life Insurance

The benefit of cooperative care of young in ensuring offspring survival even if the mother dies.

Fortress Defense

The benefit of cooperative defense of a nest or territory.

Food Distribution

The benefit of cooperative foraging and food sharing.

Conflicts of Interest

Situations where the interests of different individuals within a group are not aligned.

Sex Ratio

The ratio of males to females in a population.

Parthenogenesis

A form of asexual reproduction where offspring develop from unfertilized eggs.

Worker Policing

The behavior of workers in social insect colonies to prevent other workers from laying eggs.

Cooperation

A behavior shown by a cooperator that has been selected to be beneficial to the recipient of the behavior.

Mutual Benefit

A behavior that benefits both the actor and the recipient.

Prisoner's Dilemma Game

A game theory scenario that illustrates the challenges of cooperation when individuals have an incentive to defect.

Nash Equilibrium

A stable state in a game where no player can improve their outcome by unilaterally changing their strategy.

By-product Benefits

Benefits that arise as a side effect of an otherwise selfish act.

Reciprocity

The exchange of favors or benefits between individuals over time.

Enforcement

The use of rewards and punishments to promote cooperation and discourage defection.

***-for-Tat (TFT)

A strategy in the Prisoner's Dilemma where an individual cooperates on the first move and then repeats the opponent's previous move.

Manipulation

When one individual exploits or deceives another for its own benefit.

Seychelles Warbler

A bird species that exhibits cooperative breeding and has been extensively studied to understand the evolution of social behavior.

Observational Study

A study in which the researcher observes and records behavior without manipulating any variables.

Correlation

A statistical relationship between two or more variables.

Causation

A relationship between two or more variables where one variable directly influences the other.

Confounding Variable

A variable that is not the focus of the study but may influence the relationship between the independent and dependent variables.

Experimental Design

The plan for conducting an experiment, including the choice of variables, control groups, and experimental groups.

Data Analysis

The process of organizing, summarizing, and interpreting data collected in an experiment.