In the Canadian Arctic, calves are born between March and September, while in Hudson Bay, the peak calving period is in late June, and in Cumberland Sound, most calves are born from late July to early August.
No ártico canadense, os partos ocorren desde marzo até setembro, mentres que na baía de Hudson o pico de nacementos sucede a finais do mes de xuño, e en Cumberland Sound a maioría nacen a finais de xullo e principios de agosto.