Not the best example. We don't know why those monkeys do that, therefore we can't in good conscience automatically attribute it to pecking behavior based on dominance.

Maybe it's a punishment for antisocial behavior rather than an exusion.

Maybe monkeys who "pee in the pool" get banned from the pool.

Maybe tbose monkeys not allowed in suffered a previous heat event or cold event after getting out and this is protective.

Maybe a certain number of monkeys must be on watch against predators.

Maybe the springs can only safely contain so many at a time.

Maybe the monkeys require a certain amount of personal space before fighting breaks out.

I could go on. All those theories and more would have to be tested for to determine the cause of the behavior.