What are the costs and benefits of interactive aggregation?

Benefits

Protection from predators

Cooperative hunting

improved foraging

mate access

communal care

social transmission of info

Costs

increased competition

disease spread

cannibalism

inbreeding

obvious to predators

interference with reproduction

risk of inbreeding

Habitat has to support the entire group. E.g. otter family in ulu pandan had to move (not enough fish?)