Baleen whales are known to be some of the largest animals on Earth, and the bowhead whale is no exception. These whales are on average 50 feet long and weigh 60-80 tons. Rows of vertical baleen, or comb-like teeth that help the bowhead strain huge volumes of water to capture food, are the largest of any whale at almost 175 inches long. Additionally, a bowhead whale skull can take up almost a third of its body length, which helps the whale punch through sea ice almost 8 inches thick. But, that doesn’t mean the whales swim away unscathed. Bowhead whales have many scars on their bodies from shattering ice and these markings help scientists identify individual whales.
Bowheads are usually solitary swimmers, but will sometimes feed in groups of up to 14 individual whales. A bowhead whale’s diet consists largely of zooplankton, which they filter out through their baleen plates. Bowhead whales spend most of their day with their mouth wide open, grazing the surface for food, and a single whale may eat more than 100 metric tons of crustaceans per year. Bowhead whales also have excellent hearing— their ears are designed for low-frequency sound, which is extremely important in their underwater habitat, which is challenging to see in. Although it is difficult to tell age in a species that does not have teeth, scientists believe bowhead whales may be one of the longest-lived animals on the planet, capable of reaching more than 100 years old. (Read more about longevity secrets from marine animals on our blog!)
Bowhead whales are one of the only cetaceans that spend their entire lives in the Arctic. Rather than migrating to warmer waters when the seasons change, bowhead whales migrate within the waters of the Northern Hemisphere, including the Bering, Chukchi and Beaufort Seas. Breeding season occurs between April and June during the spring migration, and most females will give birth to a new calf every 3 to 6 years. A calf is capable of swimming on its own immediately after birth, but the mother and calf will maintain a close bond with each other for several months, rarely leaving the other’s side.
The bowhead whale was once considered economically valuable for its long baleen and thick blubber. They were commercially hunted beginning in at least the 1600s and maybe earlier. By the 1920s, the worldwide abundance had been reduced to about 3,000. The International Whaling Commission has protected bowhead whales from commercial whaling since 1946. Even so, less than 30 years ago in the 1980’s, bowhead whales were still considered endangered by the IUCN Red List. Today, populations are recovering and the species is now of least concern on the Red List Category & Criteria. However, since the 1970’s, oil and gas exploration in the Arctic has left these whales at risk for noise disturbance from seismic airguns and potential oil spills.
In the never-ending symphony of the sea, there’s a standout among the percussive pings of bottlenose dolphins and the plaintive calls of humpback whales.
These mysterious musicians are raising the bar, showing how diverse these gentle giants can be, and never singing the same tune.
New recordings of the little-studied bowhead whale show that the mammals sing intricate and variable songs—more like jazz musicians than Beethoven or Bach.
Other whale songs are predictable and simple ditties repeated over and over throughout seasons or years, says study leader Kate Stafford, a marine biologist at the University of Washington.
“With bowheads, there are lots of different songs. Every year, it’s just completely different.” (Read more about noisy animals and how they make sounds.)
For her new study, Stafford deployed special recording equipment during the winters of 2010 to 2014 in the Fram Strait, a frigid channel of water between Greenland and the Svalbard archipelago in the Arctic.
After analyzing five years of recordings of bowhead whale songs, she and her team found the animals frequently changed their songs over the season. She also found no examples of a song being reused from year to year.
“This study is really interesting and exciting,” says Laela Sayigh, a marine biologist at Woods Hole Oceanographic Institution who wasn’t involved in the new research.
Sources: – oceana.org