Can't help but think of the short story of a group of explorers encountering what turns out to be an endless space station: http://geosci.uchicago.edu/~kite/doc/roauss.htm

Orangutans are about as good as it gets at enduring solitude for apes, possibly all primates, and even then females don't live far from their mother and sisters, and children require 9 years of attention and frequent physical contact.