Enables hyaluronan synthase activity. Involved in several processes, including estrous cycle; hyaluronan biosynthetic process; and positive regulation of cell migration. Predicted to be located in cytoplasmic vesicle and plasma membrane raft. Predicted to be integral component of plasma membrane. Biomarker of diabetes insipidus; middle cerebral artery infarction; and pulmonary hypertension. Orthologous to human HAS2 (hyaluronan synthase 2). [provided by Alliance of Genome Resources, Apr 2022]