it means to use the necessary means to survive in a socially tough environment. Perhaps the culture surrounding people interaction is very intense, and one must use their wit and brains to just survive on social interaction basis. However, in today's day and age in 2017, the world is very accepting of multiculturalism, so I would presume 'social survival' won't be a term you have to use that frequently. As a native speaker, I do not come across this term regularly. Thanks for asking. Let me know if you want instant tutoring! :)