Social relationships

What reasons are there to live in groups?

• Resource related

• Predation

What are resource related reasons to live in groups?

• Communal roosting

• Cooperative hunting

• Aggregated resources

What are predation reasons to live in groups?

• reduced investment in vigilance

• dilution

• confusion

• communal defence

What does group living increase (that is negative)?

• Competiton

• Aggression

What does group size have to be a balance between?

Maximising group benefits but reducing competition

What can bigger groups lead to that is negative (other than competition?

Aggression

What size of group has the highest fitness?

Intermediate - combined effect mean intermediate gropus have the highest fitness

How can optimal group size be modelled?

Range of variables = stress hormones glutocorcidois

What size group are the more efficient foragers?

Intermediate groups

What can resource competition lead to?

Conflict and determines relationships

• Dominance hieirachies

• Egalitarian gropus

What happens in dominant heirarchies vs egalitarian groups?

• They can Monopolise resources.

• Low ranking individuals have poor access

What did Sapolski find in low ranking baboons?

High blood pressure, heart rate, low functioning immune system and brain chemistry

• Culture shift

• Wound healing + blood pressure

• High ranking male - better healing ability

What does stress do in baboons?

• Adrenaline and corticosterone response

  • decrease immune function and reproduction

  • high blood pressure and heart rate

What are coping mechanisms to reduce aggression?

• Intervention

• Reconciliation

What species do social bonds occur? What are these benefits?

Kaimanawa horse (New Zealand)

• Female more integrated into social group have better reproductive success

Amobseli baboons

• Females that have stronger bonds live longer and have more babies

Fitness benefits

What are the specific benefits of horses that are well integrated?

• Protection against confclit

• Support network

• Low level competition

What is the social brain hypothesis?

• Ratio of neocortex (executive function) bigger in larger groups

• Due to more competition, time budget constraints and more travel

  • have to problem solve more.

What does Dunbars number show ?

‘intelligent’ animals are overwhelmingly social

What is reproductive cessation ?

Where fertility declines abruptly at an advanced age

How do killer whales live in their groups?

• Matriarchal groups, strong bond with family and sons

• Lots of difference in culture

What species can retained culture be seen in, and long term memories?

• Killer Whales

• Elephants

What is there evidence that being in strong stable groups can do ?

Influence longevity, reproduction and long term memory in responding to environmental risks

How does mechanism and physiology influence social groups?

• Endorphins released with grooming

  • physiological drive to have social and affiliative relationships

• Brain region size associated with dominance in primates

What can determine group and social relationships?

Resource Distribution. predation and ecology

What is dominance associated with?

Hormonal changes and health conseuqences

What is reproductive cessation associated with?

Should be associated with fitness costs, but can have benefits