From the book Living Mammals of the World in Color by Ivan T. Sanderson, 1955From an article by Abraham Dee Bartlett appearing in Proceedings of the Zoological Society of London, 1884From the book The Breeding of Animals by Frederick Blackmar Mumford, 1917Photo by F. W. Bond appearing in the July 12, 1924 edition of Illustrated London NewsPage from The Book of the Animal Kingdom by William Percival Westell, 1910From an article on naturally occurring pike-pickerel hybrids appearing in the November 1920 issue of Forest and StreamFrom the book Wild Animals in and out of the Zoo by William M. Mann, 1930
