Humans engage in threat displays too. In modern times we have virtualised warfare - with ritualised sports events and marketplace competition between companies. Here is an example of a human threat display:
When comanies "die" or sports teams "lose", it is sometimes sad, but no human beings are typically harmed in the process. It's Darwinian evolution that has lost its sting. Evolution via differential reproductive success is largely an alternative to evolution via death.
Virtualised conflict is often better than real conflict - because it results in faster evolution and adaptation at lower cost. It has the same kinds of advantage that rapid prototyping has over building things for real. While A and B are fighting, C and D - who negotiated a truce - are off making babies, and they often out-reproduce both A and B.
Cultural evolution to date has led to a large reduction in expensive real-world conflicts. There have been rises in communication and surveillance technologies - which are capable of capturing aggressive acts and other bad deeds - and then broadcasting them widely. Also, part of the effect seems due to a rise in the use of virtualisation technology - with brain-based and computer-based simulations both progressing dramatically. The wiser we are, the less likely it is that combatants will mis-calculate the outcome of a fight - and have to fight in real life.
We should be trying to understand the factors influencing the trend towards the virtualization of conflict - so we can better ensure that it continues unabated.