a thought experiment with time

Here is a thought experiment that I was trying out today.

Question

Assume that we are in a society where there is no concept of time. You have to meet a friend. How do you two sync up so that you can meet each other. Remember that you do not have a concept of time, hence you cannot tell him 'meet me below the fourth coconut tree at 3 PM today'.

Answer (one of the many)

One answer that I think might be feasible is that you tell your friend that you will let off a firecracker (or some signaling device) when you leave your home and you will let off a firecracker after every 500 meters.

Applications of this problem

How do ants sync up between themselves ? i.e. how do they decide 'this is the time the house owner makes tea and spills some milk on the counter'