Ernest Warren, zoologist, was the son of Samuel S. Warren and his wife Elizabeth M. Dives. He studied at South-East College in Kent and University College Bristol, before entering University College, London, in 1891, graduating with first class honours in zoology in 1894. Staying on as demonstrator in zoology he continued his studies and was awarded the degree Doctor of Science (DSc) in zoology in 1898. His doctoral thesis was published in the Philosophical Transactions of the Royal Society of London (B) (1898, Vol. 189, pp. 135-227) under the title "An investigation on the variability of the human skeleton; with special reference to the Naqada race discovered by Professor Flinders Petrie in his explorations in Egypt". From 1899 he was assistant lecturer and museum curator at the University of London, with promotion to assistant professor of zoology in 1900.
In February 1903 Warren accepted an appointment as the first director of the Natal Museum, Pietermaritzburg, where he remained until his retirement in 1935. He soon produced a substantial Catalogue of some of the collections on exhibition at the Natal Government Museum (Pietermaritzburg, 1906, 149 pp). From 1910 to 1930 was also the first professor of zoology at the Natal University College (later the University of Natal), presenting his lectures and practicals at the museum. During his directorship he developed the museum as both a research centre, particularly in zoology, and an important educational institution. Under his direction the museum was greatly enlarged in 1912 by the addition of a large mammal hall, laboratories and workshops, while the collections continued to grow. Perhaps the most important collection was the large mammals of Africa, which included many rare species. He introduced new methods of display in an attempt to show the animals in their natural environment. For many years he supported the idea of a game park for Natal and a bird sanctuary at St Lucia, and as co-author with E.R. Bradfield* wrote a pamphlet on The pressing need for the protection of indigenous forests, and for afforestation in South Africa (1918?). During his early years in the colony he was an active member, and honorary secretary, of the Natal Naturalists' Association of Pietermaritzburg.
Most of the research carried out by Warren and his staff was published in the Annals of the Natal Museum, which he founded in 1906 and edited until his retirement. During this period he produced seven volumes, comprising some 3700 pages. It was soon recognised as a scientific journal of quality, as Warren's considerable technical abilities as a microscopist and scientific illustrator and his interest in evolutionary matters set a high standard. In his first paper in the Annals he described a new species of parasitic protozoan in a South African rotifer, naming it Bertramia kirkmani after the local rotifer enthusiast Thomas Kirkman*. Warren became well-known for his research on the Coelenterata, particularly the order Hydroida, describing new species from Natal, and parts of their anatomy, in a series of eight papers published in the Annals during 1906-1909, 1914 and 1919. He also made a very full study of the rain spider (now Palystes superciliosis). In a "Note on a lizard-eating S. African spider" (Annals, 1923) he reported that the rain spider sometimes feeds on small geckos. His comprehensive description of this species was entitled "On the habits, egg-sacs, oogenesis and early development of the spider Palystes natalius (Karsch)" (Ibid, 1926). Two further papers on Palystes published in the South African Journal of Science (1925, 1926) caused a stir in the arachnid world with their evidence of amitosis in the spiders' testes. Further papers by him on spermatogenesis and heredity in South African spiders appeared in the Annals in 1928, 1929, 1931 and 1933.
Warren's many other papers in the Annals - there were 50 in total - reflected his wide interests in biological subjects, for example, "Note on the abnormal hoofs of a sheep" (1906); "Note on the larva of a fly... occurring in the human intestine" (1907); "Notes on the life-histories of Natal termites, based on the observations of the late Mr G.D. Haviland*" (1909); "On some specimens of fossil woods in the natal Museum" (1912); "A case of hybridism among cockatoos" (1914); "Craniometrical data of the immature skull of a female chimpanzee" (1926); "A statistical study of certain interspecific plant hybrids and backcrosses" (1931); "On a ciliate protozoan inhabiting the liver of a slug" (1932); and "On the genital system of certain Solifugae" (1939). Some more papers by him appeared in the South African Journal of Science, the latter including "Observations on the development of the non-aquatic tadpole of Anhydrophryne rattrayi Hewitt" (1922); and "New formations in the duodenal mesentery and stomach wall of Bufo regularis Reuss" (1923).
Warren became a member of the South African Philosophical Society in 1903 and when it became the Royal Society of South Africa in 1908 was elected one of the founding Fellows of the latter. In 1916 he became a foundation member and joint vice-president of the South African Biological Society and was awarded its Senior Captain Scott Memorial Medal in 1925. He joined the South African Association for the Advancement of Science in 1907, served as president of Section D (which included zoology) in 1919 and as vice-president of the association that same year. He received the association's South Africa Medal (gold) in 1920. In 1910 he was elected joint vice-president of the newly established (but short-lived) Natal Scientific Society. A new species of snail that he collected during 1903 was named Gulella warreni (Warren's hunter snail) in his honour later that year. When he retired in 1935 he returned to Canterbury, where he was born. He was an indefatigable worker, full of energy, enthusiasm and initiative, and had wide interests.