Henry Walter Bates was an English naturalist and explorer who gave the first scientific account of mimicry in animals. He was most famous for his expedition to the rainforests of the Amazon with Alfred Russel Wallace, which took place between 1848 and 1852. Upon returning home eleven years after his departure, Bates wrote down his findings. The Naturalist on the River Amazons, published in two volumes, has become his best-known work. The first volume focuses on the events and discoveries which had taken place between their arrival in the Brazilian Amazon and their journey to the Barra of the Rio Negro.