Happy new year! This January, we are happy to feature the Sowerby’s beaked whale, also known as the North Atlantic beaked whale (Mesoplodon bidens). This rare and elusive whale is quite understudied because it spends most of its life deep under the ocean’s surface, hunting for prey. Did you know that males sometimes compete with one another, using their tusks to win females over? Find out more about Sowerby’s beaked whales!
What is a beaked whale anyway?
Beaked whales are a group of medium to large-sized whales among the least-known and least-studied cetaceans. They are characterized by their long, narrow beaks and often by the presence of a single pair of teeth in the males. Beaked whales are usually deep divers and feed primarily on squid and deep-water fish.
The Sowerby’s beaked whale is a medium-sized beaked whale: adults reach lengths of up to 5 meters and weigh up to 2 tons. This whale has a long, slender body with a small, curved dorsal fin near the tail. The whale’s coloration is dark gray on the upper body, with a lighter gray or white underside. It has a distinctive beak, which is longer in males than in females.
Sowerby’s beaked whale is a deep-water species, usually found in waters at least 1000 meters deep. It feeds on various prey, including deep-water fish and squid and can dive to depths of up to 1,500 meters in search of prey.
Males can sink their teeth into their competitors
Sowerby’s beaked whales live in small groups, and males can engage in aggressive behavior and use their tusks to compete during mating season. Scientists reported that Sowerby’s beaked whale males have long and incredibly dense rostrums that serve them well during male-male aggressions.
Their mandibles also develop so that, after the teeth (also called tusks) eruption, the area right behind the tooth becomes thick and dense to support the pressure on the bone during fights. As a result, long tusks allow males to rake and scar their opponents, while the dense bones protect the beaks from breakage during head-to-head fights. Consequently, adult males typically look more scarred than females.
Threats to Sowerby’s whales
Sowerby’s beaked whales face the same threats as other beaked whales, which include noise, ocean pollution, and entanglement in fishing gear. Efforts to protect Sowerby’s beaked whales and other beaked whale species include reducing ocean pollution and promoting sustainable fishing practices. As citizens of the world, we can bring awareness to this unknown species and encourage decision-makers to protect their environment.
Noise, in particular, can be disruptive for deep divers like beaked whales. Exposure to loud noise, like sonar, may induce intense physical responses in whales, including decompression sickness. Long-term effects of noise pollution can impact a whale population’s survival by decreasing their fitness (their ability to find food and reproduce healthily).
Entanglement in active and discarded fishing gear
Due to their deep-water habitat and feeding habits, Sowerby’s beaked whales risk being caught as a bycatch in fishing gear designed to target deep-water species. This can include longlines, trawls, and gillnets used to catch various fish and other marine animals.
In addition to the immediate threat of injury or death, entanglement in fishing gear can also have long-term impacts on the health and survival of Sowerby’s beaked whales. For example, entanglement can restrict the whale’s feeding ability, leading to malnutrition and reduced reproductive success. It can also cause wounds and infections, leading to further health problems.
Pollution and Climate Change
Exposure to pollutants such as plastic waste, chemicals, and oil poses a significant threat to Sowerby’s beaked whales and other marine species. These pollutants can enter the whale’s body through ingestion or absorption, leading to health problems and even death.
Other threats to Sowerby’s beaked whales include habitat loss and climate change. As the ocean warms and acidifies, the whales’ habitats and food sources may change or relocate up North, potentially leading to population declines.
In conclusion, the Sowerby’s beaked whale is a fascinating and little-known species of toothed whale living in the North Atlantic Ocean. Despite its lack of notoriety, this species is an important part of the ecosystem and deserves our attention and protection.
Sources and further reading:
- COSEWIC Assessment and Update Status Report on the Sowerby’s beaked whale Mesoplodon bidens in Canada
- Pitman, Robert. “Mesoplodont whales:(Mesoplodon spp.).” Encyclopedia of marine mammals. Academic Press, 2009. 721-726.
- MacLeod, Colin D. “Possible functions of the ultradense bone in the rostrum of Blainville’s beaked whale (Mesoplodon densirostris).” Canadian Journal of Zoology 80.1 (2002): 178-184.
- Macleod, C. D., & Herman, J. S. (2004). Development of tusks and associated structures in Mesoplodon bidens (Cetaceae, Mammalia).
- Wenzel, Frederick W., et al. “Food habits of Sowerby’s beaked whales (Mesoplodon bidens) taken in the pelagic drift gillnet fishery of the western North Atlantic.” (2013).
Did you enjoy learning about Sowerby’s beaked whales? Make sure to read our other posts on beaked whales here: