Why is it that only humans are ashamed of certain critical biological activities

Humans are ashamed of certain activities that are critical to our survival.
Examples: mating, defecation, exposing certain parts of our bodies

This restricts some activities from being performed while others are around (usually only if others are also humans).

Perhaps it is because we are the only species who is capable of feeling ashamed?

What are the advantages of this mechanism in terms of survival as a species?