I don't have the book to hand - it's out on loan and not due back for quite a while.....
However the book is 'Antarctic Hero' by Author Michael Smith, and all about a Tom Crean from Kerry who accompanied both Shackleton and Scott and arguably the linch-pin of the expeditions.
In the book it mentions Tom as constantly singing and humming and sometimes to the annoyance of others (folk music - really ??)
Perhaps if you can locate the book or Author - there will be some more solide info.