Neat summary and contextualization of the topic! Seems simple on the surface, which is why a nice lead through is helpful.

Last week at the zoo I watched the Chimpanzee dynamics for a good half hour or so. Very extreme by comparison to us. Loud. Chasing. Urination.

I suspect that biologically there's some overlap between Tears in Humans - which Chimps don't seem to possess the capacity to produce - and Defecation as a communication mechanism that Humans have spent a lot of time evolving away from. Each can be quite expressive.