This document discusses the challenges of large-scale data sharing between researchers. It examines two case studies: SPLASH, which studied humpback whale populations using photo identification techniques; and GAIN, which studied genetic associations. Both projects found that researchers had idiosyncratic data management systems and that fully answering key scientific questions required gathering data from new areas, which faced social and organizational barriers. The document advocates for overcoming these impediments to enable large-scale data sharing across research communities.