Lecture 1

Question 1

Tinbergen’s 4 questions

Answer 1

Mechanism (causation):
- Short term and Proximate

Ontogeny (Development):
- Longterm and proximate

Adaptive Value (function):
- Short term and Ultimate

Phylogeny (Evolution):
- Long term and Ultimate

Question 2

Mechanism (causation)

Answer 2

How does the behavior occur?
What stimuli can trigger it?
What processes respond to the stimulus to produce the behavior?

Question 3

Ontogeny

Answer 3

How does an animal’s expression of the behavior change over the animal’s lifetime?
Is it learned?
Does it develop over time?

Innate vs learned behavior (* most behavior is partially innate, partially learned)

Question 4

Adaptive Value

Answer 4

How does the behavior benefit the animal and increase its fitness?
Is there a cost/benefit tradeoff associated with the behavior?

Costs vs benefits

Question 5

Phylogeny

Answer 5

How did the behavior evolve?
Did it evolve once, or multiple times?
Is it shared by closely related species?

Homology vs Parallelism vs Convergence vs Analogy

Question 6

Innate Behavior

Answer 6

• Stereotyped
• All individuals of a species perform the behavior in a similar way (species-specific)
• Regulated by genes

Examples:
* Nest-building
* Aggression
* Mating and Courtship
* Feeding
* Parental Behavior

Question 7

Learned Behavior

Answer 7

• Flexible
• Between-individual differences in performance
• Acquired by experience (learning process)
• Affected by the environment

Types:
* Habituation
* Imprinting
* Classical conditioning
* Operant conditioning

Question 8

Benefits to group living

Answer 8

• Improved foraging
• Access to mates
• Access to shelter
• Protection from predator
• Division of labor
• Thermoregulation

Question 9

Costs to group living

Answer 9

• Increased parasites and disease
• Competition over food, space and mates
• Increased conspicuousness
• Suppressed reproduction

Question 10

Homology

Answer 10

Ancestor had the same feature

Question 11

Parallelism

Answer 11

Ancestor had initial feature that led to later similarity

Question 12

Convergence

Answer 12

More distant common ancestor

Question 13

Analogy

Answer 13

No known common ancestor

Question 14

Social Behavior

Answer 14

Interaction between at least two individuals of the same species (conspecifics)

Question 15

Sociality

Answer 15

Tendency to associate with others and to form social groups

Question 16

Social group

Answer 16

Forms and is maintained by social attraction between group members

Question 17

Social

Answer 17

Tendency of animals to live in groups for some considerable time

Question 18

Non-social behavior

Answer 18

Not aimed at conspecifics; controlled mainly by internal stimuli and physical environment

Nut in social contexts, conspecifics affect these behaviors –> Social facilitation, imitation

Question 19

Solitary species

Answer 19

Absence of permanent groups of adults (usually territorial), but presence of social networks and social behavior (e.g. territorial behavior, consorting and mating, parental care)

Question 20

Social group characteristics

Answer 20

1) Communication: +/- intensive, +/- complex

2) Longevity and stability: temporary or permanent

3) Accessibility: open or closed

4) Size and composition: related +/- unrelated individuals

5) Social relations: Individualised or anonymous, dominance, division of labor, cooperation and altruism

Question 21

Types of social groups

Answer 21

• Aggregation
• Family groups, offspring + 1 or 2 parents
• Extended family group, society
• Eusociety

Question 22

Aggregation

Answer 22

Threats, contact and alarm signals; temporary; open; large; most individuals unrelated; mostly anonymous

Question 23

Family group, offspring + 1 or 2 parents

Answer 23

Intensive communication, many signals; temporary; closed; individualised; +/- division of labor

Question 24

extended family group, society

Answer 24

Intensive communication, many signals; permanent; +/- closed; +/- related individuals; individualised, +/- dominance, division of labor, cooperation and altruism

Most variable/dynamic type of social group in vertebrates

Size and composition of groups varies within species, most extensively/frequently in fission-fusion societies.

Unrelated individuals accepted when they are essential for reproduction, but trade off between costs and benefits

Question 25

Environmental and social factors determining size and composition of extended family groups

Answer 25

- Type, amount and availability of food - Predation risk - Competition within and between individuals/groups/species

Question 26

Eusociety

Answer 26

Intensive communication, many signals; permanent; closed; often very large; related individuals; often anonymous, extreme division of labor (castes), cooperation and altruism

Question 27

Pack (African wild dogs)

Answer 27

Breeding pair and dependent pups + adult and yearling helpers

Question 28

Pack (african dogs) hunting

Answer 28

Adults and yearlings hunt in groups During: - Group hunting results in short chases through prey isolation, distraction of mothers from calfs, and kills of large prey After: - Coordinated tearing apart and carcass opening, --> Rapid carcass cleaning --> Protection of carcass Larger groups more efficient during and after hunting

Question 29

Obligate cooperative breeding of packs (African dogs)

Answer 29

Cooperation and helping is essentail for reproduction - Pregnant or suckling female, and pups < 3 months old, are fed by regurgitation (1kg/hunter/hunt) - Parts of kill carried to older pups, older pups led to kills and given priority at kills - Pup-guarding (baby-sitting) by an adult or yearling helper

Question 30

Benefits from baby-sitters

Answer 30

1) Alert pups --> pups go to safety of den 2) Move pups away from approaching larger predators and attack smaller predators or conspecifics 3) Move pups when heavy rain causes flood at den 4) Allow mothers (experienced hunters) to go back to hunting and into vital body condition sooner Pup guarding is essential for reproduction

Question 31

Costs of baby-sitters

Answer 31

1) Cannot participate in hunts --> hunting packs smaller 2) Baby-sitters consume part of regurgitated meat --> extra hunts (risky, energy costs) Small packs cannot really afford pup-guarding

Question 32

Pack size is of crucial importance

Answer 32

Pack size > 5 essential for cooperative hunting, defence from kleptoparasitism, pup feeding and pup-guarding Unusual/costly behavior maintains pack size: 1) pups given priority with food (future pack members) 2) Injured + older non-hunting dogs tolerated at kills 3) May adopt unrelated pups/juveniles 4) May accept unrelated adults Two factors determine minimum pack size (about 5): 1) hunting efficiency and protection of carcasses 2) Feeding of pups and pup-guard (mother or baby-sitter) If pack less than 5, den less chance of guard. - But always pup-guards during night hunts

Question 33

Limitations for pack size

Answer 33

Range: 2-27, but 5-15 most common Pup mortality decreases and adult mortality increases with pack size Risks and energetic demands of hunting

Question 34

Other examples of cooperative breeders

Answer 34

Babblers Meerkats Mongoose Hyenas Marmosets Wolves

Question 35

Take home message

Answer 35

Sociality= tendency to associate with others --> varies within and between species Social group characteristics: Communication, longevity and stability, accessibility, size and composition, social relations Social group types: aggregations, family group, extended family group, eusociety Extended family group = variable/dynamic Wild dogs: trade-offs of baby-sitting