The principal predators of bowheads are humans. Most caught right whales, with few venturing north to search for bowheads. A few bowheads are also taken incidentally. Eventually, it was recognized that bowheads and right whales were in fact different. Both meat and blubber (muktuk) are eaten from narwhals, belugas and bowheads. Inuit hunters have reported bowheads surfacing through of ice. There were disputes over anchored and harpooned bowheads, which led to several court battles. On average, female bowheads are larger than males. Annual catches vary between 300 and 500 belugas and 40 to 70 bowheads. Russian schooners from Mamga also cruised for bowheads in the sea from 1865 to 1871. Since bowheads range further north than right whales, hunting pressure on right whales declined rapidly. Thus, bowheads in the Sea of Okhotsk were once called "forgotten whales" by researchers. By 1849, 50 ships were hunting bowheads in each area. During breeding season, bowheads make long, complex, variable songs for mating calls. Bowheads seek the safety of the ice and shallow waters when threatened by killer whales.