The animal in question is a record-breaking goliath of its species: it has the thickest blubber, thickest skin, longest lifespan, lowest core body temperature, longest baleen, proportionally the largest mouth and head and a vocal repertoire rivalled only by a few species of songbirds. That’s impressive!
While it seems almost too spectacular to be true, these mammals are in fact bowhead whales. Danny Groves, from Whale and Dolphin Conservation, explains their weird and wonderful qualities.
When were bowhead whales first discovered?
Bowhead whales were named by Linnaeus in 1758. At that time, it was thought to be identical to its relatives, known collectively as right whales. Following the work of John Edward Gray in 1821, bowheads were proposed as a separate genus to right whales.
What oceans do bowhead whales live in?
Bowhead whales are endemic to Arctic and subarctic waters and are adapted to life in icy water. They have a very thick layer of blubber insulation, to enable them to survive in the coldest waters and some of the harshest conditions in the world.
Bowhead whales live only in the polar Arctic waters of the northern hemisphere, in mostly shallow coastal water less than 200m deep and in close association with ice floes. Bowhead movement patterns in the Arctic are mainly influenced by the melting and freezing of the ice, venturing further north during the summer months as the sea ice melts and recedes.
How did bowhead whales get their name?
The bowhead whale is named after their unique, steeply arched upper jaw and mouth which are shaped like an archer’s bow. They are also sometimes known as Arctic right whales, Arctic whales, Greenland right whales, and the Polar whale.
How long are bowhead whales?
The maximum length of a male whale is approximately 16m (52 ft) and a female whale is approximately 18m (59 ft). A calf is around 4m (13 ft).
How much do bowhead whales weigh?
The maximum weight of a bowhead whale is around 80 tonnes. A calf weighs approximately 1000kg at birth.
What are the physical characteristics of a bowhead whale?
They have two blowholes and a distinctive V-shaped blow. Unusually, bowhead whales don’t have a dorsal fin, or even a ridge or hump. As they spend so much of their time swimming around under sea ice, a dorsal fin would be an awkward inconvenience. Instead, scientists use white scars (from breaking ice, or encounters with killer whales and fishing gear) on their bodies as identifying features.
Do bowhead whales have any distinguishable features?
These large, rotund whales have wide, smooth black backs and paddle-shaped flippers. With a distinctive white chin patch, bowheads also have bellies peppered with white spots and a grey band just in front of their tails.
Can bowhead whales break ice?
Their immense heads and powerful skulls enable bowhead whales to break through sea ice 60cm thick.
Do bowhead whales have teeth?
Bowheads have no teeth and are classed as a baleen whale – they use baleen plates (thick hair-like structures, like the teeth of a comb) to filter their food from huge volumes of seawater. In fact, bowheads have the largest baleen structures of any whale, growing up to 4m (13ft) in length.
What do bowhead whales eat?
Bowheads’ favourite meals are krill and copepods, but they can also eat a range of other small invertebrates and fish. Filter-feeders, they swim along with their mouths partly open, gulping in huge volumes of water and food that they filter through their baleen.
How do bowhead whales track their prey?
Bowheads sometimes feed in coordinated echelon formation, staggered side-by-side.
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Do bowhead whales form pods?
While bowhead whales are sociable, they tend to travel solo, or in small groups of 2 or 3 individuals rather than large pods.
How do bowhead whales breathe?
Bowhead whales are faced with a number of challenges, including limited visibility and huge layers of ice that build up on the sea’s surface, restricting their access to the surface and precious oxygen.
Fortunately, bowheads have developed ways of getting around these problems. Using their strong, thick-skulled heads, they can break through sea ice of up to half a metre thick to breathe.
Do bowhead whales come to the surface for long?
The whales typically spend 9–18 minutes underwater before coming to the surface to breathe – although other, smaller whale species will put on a show when it comes to breaching. However, they may stay under the water for 40–60 minutes, and can dive to several hundred metres deep.
What's the lifespan of a bowhead whale?
Bowheads are thought to have the longest lifespan of any whale and can live up to 200 years.
This was discovered in 2007, when a team of native Alaskan whalers found a harpoon tip in the neck of a bowhead whale that they had harvested. The harpoon was dated from the 1800s – meaning that the whale had lived a further century with the detonated harpoon stuck in the blubber around its neck.
Scientists think that living in the harsh Arctic environment is the reason for the bowhead’s slow growth rate (reaching sexual maturity later) and longer life. It's also thought that bowhead whales have unusually effective DNA repair processes, which can reduce the likelihood of developing cancer, for example.
How fast can bowhead whales swim?
Bowheads are relatively slow swimmers, with an average speed of 2–5 km/hour – although they can swim faster (around 10 km/hour) for short periods, if disturbed. In fact, they don’t do anything particularly quickly. Understandably, they try to conserve their energy because of the extreme environment around them.
Why do bowhead whales sing?
Bowhead whales are highly vocal, producing a wide variety of vocalisations including moans and complex songs (complex, distinct musical phrases that are learned). This is rare among mammals – although it's been discovered that humpback whales can learn new songs from other populations.
A study undertaken east of Greenland found that bowheads had a new set of songs each season, which led to them being described as 'jazz singers of the deep'. Unlike humpback whale song (which is likened to classical music), bowhead whale song is much more freeform and unrepetitive. It's thought that songs may be used to navigate, find food and communicate, but it's unclear why they have so many different song types and why the songs change each year.
How do bowhead whales breastfeed underwater?
They breastfeed in the same way as other whales and dolphins. The calf inserts its tongue into the mammary slit of the mother and the nipples (which are normally inverted) eject milk into the baby’s mouth.
How long do bowhead whale calves stay with its mother?
Making sure they stay well-nourished in their Arctic homes, baby bowheads stay with their mothers for about a year, drinking plenty of milk while they grow.
Do bowhead whales have natural predators?
Orcas will attack bowheads.
How do bowhead whales protect themselves from predators?
Bowheads may follow migratory patterns that reduce exposure to predators. Mothers with young may use the ice floes and leads to try to avoid attacks.
What are the main threats to bowhead whales?
Human threats – include entanglement in fishing gear, and ship strikes and disturbance from underwater noise that is related to expansion of oil and gas exploration, shipping and fishing in the Arctic.
Climate change – melting ice in the Arctic poses ongoing challenges for bowhead whales, as they depend on sea ice for their habitat.
Pollution – chemicals, heavy metals, plastics and oil spills can harming their health and their ability to have young.
Hunting – bowhead whales are subject to aboriginal subsistence hunts in the US, Russia, Greenland and Canada. Today, the hunts are protected under the Marine Mammal Protection Act and hunting is allowed for registered members of the Alaska Eskimo Whaling Commission. A quota for the number of whales harvested is determined by the International Whaling Commission (IWC). The hunts in Canada are regulated by its government in collaboration with Indigenous groups.
Are bowhead whales endangered?
Bowhead whale populations were severely reduced due to extensive commercial whaling in the 17th–19th centuries, as they were highly valued for their blubber, baleen and oil. Protection from commercial whaling in recent times has meant that there are an estimated 25,000 bowhead whales, and globally they're listed as Least Concern by the IUCN.
However, three subpopulations of bowhead whale are less numerous. Both the East Greenland-Svalbard-Barents Sea subpopulation and Okhotsk Sea subpopulation are classified as Endangered by the IUCN.
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