Born in
St. Louis County, Missouri, Losos studied biology at
Harvard University, from which he received a bachelor's degree in 1984. Later on, in 1989, he received a PhD in
Zoology from the
University of California, Berkeley (
Ecomorphological Adaptation in the Genus Anolis). Starting in 1987, he worked as a
teaching assistant in Berkeley. After receiving his PhD, he moved to the
University of California, Davis in 1990 to become one of the inaugural
postdoctoral fellows at the Center for Population Biology. Losos then, from 1992 on, was
assistant professor at
Washington University in St. Louis, and then was promoted to the rank of
associate professor in 1997 and
professor in 2001. His work focuses on a wide range of topics, but he is best known for his studies of
convergent evolution and
adaptive radiation, and for experimental studies of evolution in nature. Most of his empirical work has involved the evolutionary radiation of lizards in the genus
Anolis which occur in Central and South America and on islands in the
Caribbean. More recently, he has also begun to study the evolution and ecology of domestic cats. From 2000 to 2003 and 2004–2005, Losos was director of
Tyson Research Center at
Washington University in St. Louis. In 2006, Losos left Washington University to become the
Monique and Philip Lehner Professor for the Study of Latin America at
Harvard University and
Professor in the Department of
Organismic and Evolutionary Biology, as well as
Curator in
Herpetology of the
Museum of Comparative Zoology. Losos then returned to
Washington University in St. Louis College of Arts and Sciences in 2018 to become the William H. Danforth Distinguished University Professor in the Department of Biology, as well as the founding director of the Living Earth Collaborative, a biodiversity partnership between Washington University in St. Louis, the
Missouri Botanical Garden and the
Saint Louis Zoo. ==Honors and awards==