20th-century German zoologists

Ernst Ludwig Bresslau (10 July 1877, Berlin – 9 May 1935, São Paulo) was a German zoologist. He was the son of historian Harry Bresslau.

Ludwig Paul Koch (13 November 1881 – 4 May 1974) was a broadcaster and sound recordist. An expert on recording animal sounds, he played a significant part in increasing the British public's appreciation of wildlife.

Caesar Rudolf Boettger (20 May 1888 – 8 September 1976) was a German zoologist born in Frankfurt am Main. He specialized in malacology, particularly studying the land snails and slugs.
In 1912 he obtained his PhD from the University of Bonn, and in 1914 embarked on a scientific expedition to Africa and the Orient. During World War I, he was stationed in France and Turkey. In 1932 he became a private lecturer at the University of Berlin, where in 1938 he was appointed professor of zoology. In 1947 he became a professor of zoology at Braunschweig University of Technology, where he established a museum of natural history.
After retirement in 1956, he undertook five research trips to North America (including Mexico and Hawaii). In 1965 he was visiting curator at the University of Michigan and in 1967/68 took part in a research project of the Naval Medical Field Research Laboratory in North Carolina. Boettger has over a dozen species named after him, as well as a gastropod genus:
Boettgerilla Simroth, 1910.Caesar Boettger is commemorated in the scientific name of a species of lizard, Gallotia caesaris.
He was a nephew of German herpetologist Oskar Boettger.

Hugo Merton (18 November 1879 in Frankfurt am Main – 23 March 1940 in Edinburgh) was a German zoologist.
He studied sciences at the University of Heidelberg. From October 1907 to August 1908, with herpetologist Jean Roux, he conducted scientific investigations in the Aru and Kei Islands. In 1913 he obtained his habilitation at Heidelberg with a dissertation on the flatworm genus Temnocephala. Because of the 1935 Nuremberg Laws imposed by the Nazis, he was forced to relinquish his position as deputy director at the Senckenberg Museum in Frankfurt as well as his professorship at the University of Heidelberg.In 1937, by way of an invitation from Professor F. A. E. Crew, he went to the University of Edinburgh, where he spent time working in the institute of animal genetics. Upon this return to Germany in 1938, he was arrested and imprisoned in the concentration camp at Dachau. During the following year, he was deported to Scotland, where he resumed his work at the university. Due to deteriorated health, he died soon afterwards in March 1940.Organisms with the specific epithet of mertoni are named in his honor, an example being the sea snake species Parahydrophis mertoni. In 1911, Max Carl Wilhelm Weber named the fish species Pseudomugil gertrudae after Merton's wife, Gertrude.

Karl Dietrich Gerhard Barfurth (25 January 1849 – 23 March 1927) was a German anatomist and embryologist born in Dinslaken.
He studied mathematics and sciences at the University of Göttingen, and medicine (1879–1882) at the University of Bonn. In 1882 he earned his medical doctorate, and in 1883 received his habilitation in anatomy. In 1888 he worked as prosector under Friedrich Sigmund Merkel (1845–1919) in Göttingen. From 1889 to 1896 he was a professor of anatomy, embryology and histology at the University of Dorpat, and afterwards was professor of anatomy at the University of Rostock and director of the institute of anatomy.
Barfurth is remembered for regeneration research of body parts (tissues, limbs, organs, etc.) in animals at the embryonic, larval and adult stages of life. He was the author of the following works on regeneration:

Regeneration und Transplantation (1917)
Methoden zur Erforschung der Regeneration bei Tieren (Methods for the Study of Regeneration in Animals) (1920)

Bernhard Klemens Maria Grzimek (German pronunciation: [ˈɡʒɪmɛk]; 24 April 1909 – 13 March 1987) was a German zoo director, zoologist, book author, editor, and animal conservationist in postwar West Germany.

Oscar Hertwig (21 April 1849 in Friedberg – 25 October 1922 in Berlin) was a German embryologist and zoologist known for his research in developmental biology and evolution. Hertwig is credited as the first man to observe sexual reproduction by looking at the cells of sea urchins under the microscope.

Karl Alfred Ritter von Zittel (25 September 1839 – 5 January 1904) was a German palaeontologist best known for his Handbuch der Palaeontologie (1876–1880).