Cuvier's beaked whale

The Cuvier's beaked whale or goose-beaked whale (Ziphius cavirostris) is the most widely distributed of all beaked whales in the family Ziphiidae.[3] It is smaller than most baleen whales yet large among beaked whales. Cuvier's beaked whale is pelagic, inhabiting waters deeper than 1,000 feet (300 m). It has the deepest and longest recorded dives among whales at 9,724 feet (2,964 m) and 122 minutes respectively, though the frequency and reasons for these extraordinary dives are unclear.[4][5] Despite its deep water habitat, it is one of the most frequently spotted beached whales.[6]


Cuvier's beaked whale
Temporal range: Pliocene-recent[1]
Size compared to an average human
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Ziphiidae
Genus: Ziphius
Cuvier, 1823 [2]
Species:
Z. cavirostris
Binomial name
Ziphius cavirostris
Cuvier, 1823 [2]
Range of Cuvier's beaked whale

The genus name Ziphius comes from Greek xiphos "sword" and the species name cavirostris from Latin cavus "hollow" and rostrum "beak", referring to the indentation on the head in front of the blowhole.[7]

Taxonomy

French naturalist and zoologist Georges Cuvier first described the species in Recherches sur les ossements fossiles ("Research on Fossil Bones", 1823)[8] based on a skull found on the Mediterranean coast of France at Fos-sur-mer, Bouches de Rhone. He named it Ziphius cavirostris from the Latin cavus for "hollow" or "concave", referring to the prenarial basin, a deep hollow in the skull which is a diagnostic trait of the species. Baron Cuvier believed the skull represented the remains of an extinct species. Later, in 1850, paleontologist and zoologist Paul Gervais found the skull to be identical with that of a whale carcass more recently stranded on a beach.[9]

Cuvier's beaked whale is the only member of the genus Ziphius, and is one of 22 species in the family Ziphiidae.

Description
Skeleton and skull of Cuvier's beaked whale

The body of Cuvier's beaked whale is robust and cigar-shaped, similar to those of other beaked whales, and can be difficult to distinguish from many of the mesoplodont whales at sea. The body of adult males is typically a dark gray, with their head being distinctly lighter, or even white. This light coloration extends along the posterior. Females vary in color from dark gray to a reddish-brown. The skin lightens on female's head to a lesser extent than in males, and does not extend along the posterior.[10] Cuvier's beaked whales are usually born weighing about 500 pounds and between 6.8 and slightly over 8 feet long. Calves are black or dark blue with a white belly. Females reach maturity at an average of 19 to 23 feet long and the males at 19 to 22.5 feet, weighing about 2 to 3.5 tons.[11]

Cuvier's beaked whale is an odontocete — or toothed whale. Males develop two tusks in the right and left corners of their lower jaw and have otherwise a set of peg-like teeth, which may have no practical use or be vestigial teeth only. The females have these same teeth ––or lack of them––without the two tusks. The tusks are possibly used for dueling between the males, though it has not been observed. They may compete for females, but the tusks may also be used for fighting off threats such as orcas. The adults, especially the males, have many scars along their sides which can be used to identify individuals. The scars are thought to be from battles with males, predators, fights with squid, or cookiecutter sharks, which may score them or punch holes directly in their sides.

Diving deep to catch prey, they open their jaws in a way that creates suction. A pair of throat grooves allows the whale to expand this region when sucking in its prey. This type of jaw and muscular construction makes them appear to have a smiling appearance. Their skull has an indentation, and is shaped like a grooved bike helmet on top of a goose-like nose, giving it the "beak" name. All the beaked whales have this general appearance, but Cuvier's beaked whale has a shorter beak compared to others in the family Ziphiidae. They have a slightly bulbous melon, which can be either white or sometimes browner for females. Cuvier's beaked whale has a particularly gradually sloping head leading to the melon and a small, softly defined rostrum, which gives them their nickname or alternative name goose-beaked whale.[10]

Ecology

Diving

Considering Cuvier beaked whale's ability to dive to almost 10,000 feet and remain underwater for hours, there are suggestions that they may be able to collapse their rib cage and possibly lungs. They are observed to make a leaping flourish when entering a dive into the pelagic depths.

In 2014, scientists reported that they had used satellite-linked tags to track Cuvier's beaked whales off the coast of California, and found that one animal dived up to 2,992 m (9,724 feet) below the ocean surface, which represents the deepest dive ever documented for any mammal.[4][12][13][14] Another study, published in 2020, reported a Cuvier's beaked whale making a dive that lasted 222 minutes, which represents the longest dive ever documented for any mammal.[5][15] Supervising scientist Nicola Hodgkins noted that "the recorded dive time of more than three hours is likely not typical, and instead the result of an individual pushed to its absolute limits." Exposure to high noise levels from a nearby military sonar is likely to have caused the abnormal behavior.[15]

Food and foraging
Cuvier's beaked whale surfaces in the Ligurian Sea
Cuvier's beaked whale surfaces in the Ligurian Sea

Cuvier's beaked whales feed on several species of squid, including Cranchiidae, Onychoteuthidae, Brachioteuthidae, Enoploteuthidae, Octopoteuthidae, and Histioteuthidae, as well as deep-sea fish.[16] Scientists have used beached specimens to study the whale's eating habits via stomach analysis;[17] however, despite decades of research, the results have been largely inconclusive. Comparing the stomachs of the whales found in the Pacific Ocean to those found in the Mediterranean found that the Mediterranean whales predominantly ate squid from a 1,000 to 2,000-foot level, whereas in the Pacific, the whales found in Monterey, California in 2015, Taiwan in 1995, Alaska, and Baja California had access to much deeper water.

As well as catching prey in the Benthopelagic zone, they consumed a mixture of crustaceans and cephalopods further down in the Bathypelagic zone. Molluscs and octopus only found in these deep-sea regions are also sometimes eaten in the Bathypelagic zone. About 92% of the Cuvier's beaked whale diet comprises various types of squid, which depending on where the whales are diving for can be either Mesopelagic or bathypelagic squid. The squid are of many different sizes and around 37 varieties.

A whale retrieved in Monterey in 2015 was observed to have eaten 200 squids, five fish, and one very deep-sea shrimp. The shrimp and most of the squid were seemingly bathypelagic, and the fish were giant grenadiers off the bentopelagic ocean bottoms. It appears that Cuvier's beaked whale prefers diving deep and using its suction process to acquire fish. The "melon" of the whale, the bump on top of its head, contains its organ for echolocation. This means the whale can use sound waves to locate potential sources of food, which is helpful in the deep sea, where there is no sunlight. This deep diving with echolocation seems to help Cuvier's beaked whales avoid competition for their prey.

Range and habitat

Cuvier's has a cosmopolitan distribution in deep, offshore waters from the tropics to the cool, temperate seas. In the North Pacific, it occurs as far north as the Aleutians and in the North Atlantic as far north as Atlantic Canada in the west to the Shetlands in the east. In the Southern Hemisphere, it occurs as far south as Tierra del Fuego, South Africa, southern Australia, New Zealand, and the Chatham Islands. It also frequents such inland bodies of waters as the Gulfs of Mexico and the Caribbean and Mediterranean Seas.[18] The Mediterranean population might be genetically distinct from the North Atlantic population(s).[19]

Cuvier's beaked whale may be one of the most common and abundant of the beaked whales, with a worldwide population likely well over 100,000. An estimated 80,000 are in the eastern tropical Pacific, nearly 1,900 are off the west coast of the United States (excluding Alaska), and more than 15,000 are off Hawaii.[20]

Interactions with humans
A whale beached in Newfoundland

Whaling and fishing

Before 1955, it is estimated that Japanese whalers caught anywhere from 3 to 35 Cuvier's every year.[20] From 1955 until the 1990s, more than 4,000 Cuvier's beaked whales were reportedly caught. The species has been reportedly been caught incidentally in fisheries in Colombia, in the Italian swordfish fishery, and in a drift gillnet fishery off California and Oregon on the U.S. west coast, where between 22 and 44 individuals died each year from 1992 to 1995.[20] Cuvier's beaked whale is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS) and the Agreement on the Conservation of Cetaceans in the Black Sea, the Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS). The species is further included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macronesia (Western African Aquatic Mammals MoU) and the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MoU).[21]

Sonar and military maneuvers

Cuvier's beaked whale seems to have a bad reaction to sonar. Strandings and beachings often occur near naval bases where sonar may have been in use. Cuvier's beaked whale has been observed in Hawaii avoiding diving for food or avoiding an area where sonar is in use. A higher incidence of strandings has been recorded in noisy seas such as the Mediterranean and multiple mass strandings have occurred following operations by the Spanish Navy in the Canary Islands.[22][23] In 2019, a review of evidence on the mass strandings of beaked whales linked to naval exercises where sonar was used concluded the effects of mid-frequency active sonar are strongest on Cuvier's beaked whales but vary among individuals or populations, and the strength of the whales' response may depend on whether the individuals had prior exposure to sonar. The report considered the most plausible explanation of the symptoms of decompression sickness such as gas embolism found in stranded whales to be the whales' response to sonar. It noted no more mass strandings had occurred in the Canary Islands once naval exercises using sonar were banned there, and recommended the ban be extended to other areas such as the Mediterranean, where mass strandings continue to occur.[24][25]

See also

References
  1. "Ziphius cavirostris Cuvier 1824 (Cuvier's beaked whale)". PBDB.
  2. William Perrin (2014). Perrin WF (ed.). "Ziphius Cuvier, 1823". World Cetacea Database. World Register of Marine Species. Retrieved 16 March 2015.
  3. Grzimek, Bernhard (2003). Hutchins, Michael; Kleiman, Devra G.; Geist, Valerius; et al. (eds.). Grzimek's Animal Life Encyclopedia, Vol 15, Mammals IV (2nd ed.). Farmington Hills, MI: Gale Group. ISBN 0-7876-5362-4.
  4. Schorr, Gregory S.; Falcone, Erin A.; Moretti, David J.; Andrews, Russel D. (26 March 2014). "First Long-Term Behavioral Records from Cuvier's Beaked Whales (Ziphius cavirostris) Reveal Record-Breaking Dives". PLOS ONE. 9 (3): e92633. Bibcode:2014PLoSO...992633S. doi:10.1371/journal.pone.0092633. PMC 3966784. PMID 24670984.
  5. Quick, Nicola J.; Cioffi, William R.; Shearer, Jeanne M.; Fahlman, Andreas; Read, Andrew J. (15 September 2020). "Extreme diving in mammals: first estimates of behavioural aerobic dive limits in Cuvier's beaked whales". The Journal of Experimental Biology. 223 (18): jeb222109. doi:10.1242/jeb.222109. PMID 32967976. S2CID 221886321.
  6. "Cuvier's Beaked Whale (Ziphius cavirostris)". NOAA. 15 January 2015. Archived from the original on 30 March 2017. Retrieved 29 March 2017.
  7. "Cuvier's Beaked Whales, Ziphius cavirostris". The MarineBio Conservation Society (MarineBio). Retrieved 18 January 2021.
  8. Cuvier, Georges (1823). Recherches sur les ossemens fossiles (in French). 5 (2nd ed.). Paris. pp. 350–2, fig. 7. Retrieved 3 February 2013.
  9. Turner, W (1872). "On the occurrence of Ziphius cavirostris in the Shetland Seas, and a comparison of its skull with that of Sowerby's whale (Mesoplodon Sowerbyi)". Transactions of the Royal Society of Edinburgh. Edinburgh. 26 (4): 759–80. doi:10.1017/s0080456800025618. OCLC 26145032.
  10. Heyning, John E.; Mead, James G. (2009). "Cuvier's Beaked Whale". Encyclopedia of Marine Mammals. pp. 294–295. doi:10.1016/B978-0-12-373553-9.00069-9. ISBN 978-0-12-373553-9.
  11. "Cetacean Research & Rescue Unit | Cuvier's beaked whale". www.crru.org.uk. Retrieved 2020-12-08.
  12. Lee, Jane J. (2014-03-26). "Elusive Whales Set New Record for Depth and Length of Dives Among Mammals". National Geographic. Archived from the original on 2014-03-29.
  13. "How low can you go? This whale is the champion of deep diving". March 26, 2014 – via in.reuters.com.
  14. "The Globe and Mail".
  15. McGrath, Matt (24 September 2020). "Mysterious beaked whale smashes mammal diving record". BBC News.
  16. Evans, Peter GH (1987). The Natural History of Whales and Dolphins. New York: Facts on File Publications. ISBN 0816017328. OCLC 14271801.
  17. West, Kl; Walker, Wa; Baird, Rw; Mead, Jg; Collins, Pw (4 July 2017). "Diet of Cuvier's beaked whales Ziphius cavirostris from the North Pacific and a comparison with their diet world-wide". Marine Ecology Progress Series. 574: 227–242. Bibcode:2017MEPS..574..227W. doi:10.3354/meps12214.
  18. Reeves, Randall R; Stewart, Brent S; Clapham, Phillip J; Powell, James A (2002). National Audubon Society Guide to Marine Mammals of the World. Alfred A. Knopf. p. 254. ISBN 0375411410.
  19. D. Holcer D.. Fortuna M.C.. Mackelworth C. P.. 2014. Status and Conservation of Cetaceans in the Adriatic Sea (pdf). United Nations Environment Programme. Mediterranean Action Plan. Regional Activity Centre for Specially Protected Areas. Retrieved on September 04, 2017
  20. Taylor, B. L.; Baird, R.; Barlow, J.; Dawson, S. M.; et al. (2008). "Ziphius cavirostris". IUCN Red List of Threatened Species. 2008. Retrieved 3 February 2013.
  21. "Species". CMS.
  22. "Lethal Sounds: The use of military sonar poses a deadly threat to whales and other marine mammals". NRDC. June 2006. Retrieved 3 February 2013.
  23. Faerber, Meghan M.; Baird, Robin W. (March 2010). "Does a lack of observed beaked whale strandings in military exercise areas mean no impact has occurred? A comparison of stranding and detection probabilities in the Canary and the main Hawaiian Islands". Marine Mammal Science. doi:10.1111/j.1748-7692.2010.00370.x.
  24. Bernaldo de Quirós, Y.; Fernandez, A.; Baird, R. W.; Brownell, R. L.; Aguilar de Soto, N.; Allen, D.; Arbelo, M.; Arregui, M.; Costidis, A.; Fahlman, A.; Frantzis, A.; Gulland, F. M. D.; Iñíguez, M.; Johnson, M.; Komnenou, A.; Koopman, H.; Pabst, D. A.; Roe, W. D.; Sierra, E.; Tejedor, M.; Schorr, G. (30 January 2019). "Advances in research on the impacts of anti-submarine sonar on beaked whales". Proceedings of the Royal Society B: Biological Sciences. 286 (1895): 20182533. doi:10.1098/rspb.2018.2533. PMC 6364578. PMID 30963955.
  25. Batchelor, Tom (30 January 2019). "Scientists demand military sonar ban to end mass whale strandings". The Independent.

Bibliography
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