Hydrolyzes high molecular weight hyaluronic acid to produce an intermediate-sized product which is further hydrolyzed by sperm hyaluronidase to give small oligosaccharides. Displays very low levels of activity. Associates with and negatively regulates MST1R (By similarity). Random hydrolysis of (1->4)-linkages between N-acetyl-beta-D-glucosamine and D-glucuronate residues in hyaluronate. Interacts with MST1R (By similarity). Interacts with Jaagsiekte sheep retrovirus (JSRV) envelope proteins. Acts as a receptor for the Jaagsiekte sheep retrovirus (JSRV), which induces ovine pulmonary adenocarcinoma. A possible mechanism is that binding to JSRV envelope proteins may liberate the oncogenic factor MST1R that is normally negatively regulated by HYAL2, leading to oncogenic transformation. Belongs to the glycosyl hydrolase 56 family.