Redmond O’Hanlon and Rudi Rotthier, The Fetish Room: The Education of a Naturalist (Profile Books, 2011), 224 pages, £12.99  With his mutton-chop whiskers and snowy-white hair, Redmond O’Hanlon looks like everybody’s idea of the retired nineteenth-century naturalist. In thirty years, he has written some of the most colourful, funny and archly mischievous travel books around. His Congo Journey (1996), an account of a six-month trip through the northern Congo basin rainforest, is now a Penguin Classic, although equally of interest are Into the Heart of Borneo (1984), an expedition up the Rajang river in Sarawak with the poet James Fenton…