Westerlund was born at Berga in
Kalmar County, Sweden. He became a student in
Uppsala University in 1853 and studied at
Lund University where he received his bachelor's degree in 1860 and became a
Ph.D. in 1862. Westerlund contributed much to the knowledge of the land and freshwater molluscs of the
palearctic region, despite working under unfavourable conditions. His largest work was
Fauna der in der paläarctischen Region... lebenden Binnenconchylien in 9 volumes published 1884–1890. He also contributed papers in
ornithology and
botany. ==Works==