Abraham Trembley (3 September 1710 – 12 May 1784 Geneva) was a Genevan naturalist. He is best known for being the first to study freshwater polyps or hydra and for being among the first to develop experimental zoology. His mastery of experimental method has led some historians of science to credit him as the "father of biology".
He also wrote on religion and morals.
Trembley came from an officer's family from Geneva, Republic of Geneva.
He was uncle to Charles Bonnet, with whom he corresponded regularly, as well as to René-Antoine Ferchault de Réaumur (1683–1757) and Lazzaro Spallanzani (1729–1799). Trembley acted as tutor to the two children of Count Willem Bentinck van Rhoon (1704–1774), a prominent Dutch politician at the time. The boys were 3 and 6 when Trembley, during lessons in which he went fishing in the ponds outside the house, accidentally discovered the regenerative powers of the Hydra. Those lessons took place at the Count's summer residence of Sorgvliet nearby The Hague. Sketches and drawings of his experiments with the children, made by Cornelis Pronk, are kept in the archives of the town of The Hague, the Netherlands.
While Trembley thought he had discovered a new species, Leeuwenhoek had in fact first published on hydra in a 1702–1703 volume of Philosophical Transactions of the Royal Society, describing them as a type of "animalculum". In his work Leeuwenhoek clearly described the process of budding, as well as their tentacles' contractility and the presence of cnidocyte batteries on tentacles.
File:Abraham Trembley's laboratory.png|Trembley's laboratory at Zorgvlied, as depicted in his 1744 book. Judging from his correspondence, though, his laboratory was in fact much more crowded with objects, such as up to 140 jars.
File:Hydra by Abraham Trembley.jpg|A ''hydra'' as depicted in Trembley's 1744 book.
File:Aquatic microscope-MHS 10-P5200273-gradient.