To clarify, Darwin was not the naturalist of the H.M.S. Beagle. He was a companion to the captain, because societal standards did not allow captains and crew to converse, but the captain had to talk to somebody, or go crazy. The official naturalist was actually some poor working stiff who left the ship a few months into the voyage, since he could not serve as naturalist without Darwin constantly doing whatever he did, but more so because Darwin was rich.