This type of harpoon has not been used to hunt whales since the late 1800s.  Though not a parasite, whale barnacles latch onto the skin of a whale during their larval stage. Flipper movement is continuous. They grow very rapidly during their first year, after which they hardly increase in size for several years. Killer Whales vs. Fin Whale. Distribution patterns of whales in this regions are largely affected by presences of killer whales, and bowheads can disappear from normal ranges due to recent changes in killer whales' occurrences within the bay possibly because of changes in movements of ice floes by climate change.  Generally, a mother and calf pair, when faced with the threat of a killer whale pod, will either fight or flee. The Alaskan villages that participate in the bowhead subsistence harvest include Barrow, Point Hope, Point Lay, Wainwright, Nuiqsut, Kaktovik, Gambell, Savoonga, Kivalina, Wales, and Little Diomede. Its mouth can be 16 feet long and its tongue weighs one ton. , The Western Arctic bowhead population, also known as the Bering-Chukchi-Beaufort population, has recovered since the commercial harvest of this stock ceased in the early 1900s. This predominantly Arctic species is associated with ice floes. It is the only baleen whale endemic to the Arctic and subarctic waters, and is named after its characteristic massive triangular skull, which it uses to break through Arctic ice.  By 1852, 220 ships were cruising around the Bering Strait region, which killed over 2,600 whales. Baleen whales have two blowholes. A 2011 study estimated that the Western Arctic population was 16,892 (95% CI: 15,074-18,928), more than triple the population estimate in 1978. Hunted by commercial whalers until the last century for whale oil and baleen, bowhead whales are still recovering slowly from their economic extinction. The first descriptions date back to the 1840s of bones and baleen plates resembling a smaller version of the right whale, and was named Balaena marginata.  In the smallest rorqual, the minke whale, 3 m (10 ft) calves are born after a 10-month pregnancy and weaning lasts until it has reached about 5 to 5.5 m (16 to 18 ft) after 6–7 months. WWF welcomed the creation a nature sanctuary in the region. (2012). , Baleen whales have rarely been kept in captivity.  Other bowhead whales were estimated to be between 135 and 172 years old. Their nostrils, or blowholes, are situated at the top of the cranium. , Eschrichtiidae consists of only one living member: the gray whale (Eschrichtius robustus). While, unlike a modern baleen whale, Janjucetus lacked baleen in its jaw, the anatomy shows sufficient similarity to baleen whales. Balaenids are distinguished by their enlarged head and thick blubber, while rorquals and gray whales generally have a flat head, long throat pleats, and are more streamlined than Balaenids. "Anatomy & Physiology".  It is largely unknown how sound is received by baleen whales. However, a 2014 study suggests that the pelvic bone serves as support for whale genitalia. The Alaska Eskimo Whaling Commission co-manages the bowhead subsistence harvest with the National Oceanic and Atmospheric Administration. Lung volume is relatively low compared to terrestrial mammals because of the inability of the respiratory tract to hold gas while diving. Würsig, B. and C. Clark (1993). Breeding season is observed from March through August; conception is believed to occur primarily in March when song activity is at its highest. , When swimming, baleen whales rely on their flippers for locomotion in a wing-like manner similar to penguins and sea turtles. This is probably because they feed on slow or immobile prey, combined with the fact that most sunlight does not pass 9.1 meters (30 ft), and hence they do not need acute vision. , Baleen whales have a relatively small brain compared to their body mass. Rorquals also tend to be longer than the latter. , Migratory movements may also reflect seasonally shifting patterns of productivity. They are surrounded by a fleshy ridge that keeps water away while the whale breathes. , Mysticetes are also known as baleen whales because of the presence of baleen.