Explorers are a lonely lot. When a person refuses to stay in one spot for very long, he is hard-pressed to develop lasting relationships. [John] Muir portrayed himself as the gentle, happy spirit of California – but he was forever taking off for places like the Arctic and the Amazon, and if he did not in fact sacrifice his family for the sake of wilderness, he certainly sacrificed his family life. Of course, one reason many explorers leave in the first place is that standard social relationships don’t work very well for them.
from Sachs’s The Humboldt Current, p29
David Evans' personal blog 
We just read a book about Earnest Shakelton and the Endurance for book group. This was a big topic of discussion.