It is clear that a sense of brotherhood has developed among the members of the unit. Why do such feelings develop among soldiers?

When men go through traumatic experiences, they build bonds that most of us could never understand. There's a comraderie that develops between men who live together, fight together, and struggle to stay alive together that cannot be duplicated. In regard to similar feelings (other than war), competetive, team sports would be a very good example. Competetive sports (football, hockey, baseball, ect.), requires dedication, team work, loyalty, and a sense of togetherness...... success has nothing to do with an individual, but rather the group. Teammates spend inordinate amounts of time together; they travel together, house together, eat together, practice together...... and perform together.