La traduction française de cette page sera bientôt disponible.Sperm whales are the largest toothed cetacean. The size of most large baleen whales, they actually have teeth on their bottom jaw, used to grasp large squid or fish, unlike other large whales that filter smaller denser prey through their baleen. Almost mythical creatures, sperm whales were historically feared and revered in cultures around the world. The famous 19th century novel, Moby Dick, featured a sperm whale, and was based on the experiences of ‘Yankee whalers’ that roamed the world’s oceans hunting whales from small open boats in the 1800’s. Though not the largest species of whale, it does have the largest head and the largest brain of any animal on the planet; can dive deeper than almost any other marine mammal; and lives in a stable and complex matrilineal society similar to that of elephants. Sperm whales are usually found in deep oceanic waters, but can be observed closer to shore around islands or areas where underwater canyons or a narrow continental shelf provide deep water nearshore habitat.
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Not to be confused with
Sperm whales are easy to identify from a distance due to their unique blow- which projects forward and slightly to the left (however, observers should be aware that wind can also cause blows of other species to blow one way or another). While their small humps of dorsal fins may look similar to those of gray whales or humpback whales, sperm whales will be easy to distinguish at close range due to their square heads and wrinkled skin.
Sperm whales are found in deep open waters, or around islands and coastal areas with deep canyons or very narrow continental shelves. Only males tend to be observed closer to the poles beyond approximately 40° S or 40° N1,2.
Sperm whales are native or seasonally present in the following countries and territories: Albania; Albania; Algeria; Angola; Antarctica; Antigua and Barbuda; Argentina; Australia; Bahamas; Bangladesh; Barbados; Belgium; Belize; Benin; Bonaire, Sint Eustatius and Saba; Brazil; Brunei Darussalam; Cameroon; Canada; Cape Verde; Chile; China; Colombia; Comoros; Costa Rica; Croatia; Curaçao; Cyprus; Denmark; Djibouti; Dominica; Dominican Republic; Ecuador; Egypt; El Salvador; Equatorial Guinea; Falkland Islands (Malvinas); Faroe Islands; Fiji; France; Gabon; Gambia; Ghana; Gibraltar; Greece; Greenland; Grenada; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti; Honduras; Iceland; India; Indonesia; Iran, Islamic Republic of; Ireland; Israel; Italy; Jamaica; Japan; Kenya; Kiribati; Korea, Democratic People's Republic of; Korea, Republic of; Lebanon; Liberia; Libya; Madagascar; Malaysia; Maldives; Malta; Marshall Islands; Mauritania; Mauritius; Mexico; Micronesia, Federated States of ; Monaco; Morocco; Mozambique; Namibia; Nauru; Netherlands; New Zealand; Nicaragua; Nigeria; Niue; Norway; Oman; Pakistan; Palau; Panama; Papua New Guinea; Peru; Philippines; Portugal; Russian Federation; Saint Helena, Ascension and Tristan da Cunha; Saint Kitts and Nevis; Saint Lucia; Saint Martin; Saint Vincent and the Grenadines; Samoa; Sao Tomé and Principe; Senegal; Seychelles; Sierra Leone; Singapore; Slovenia; Solomon Islands; Somalia; South Africa; Spain; Sri Lanka; Suriname; Syrian Arab Republic; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Togo; Tonga; Trinidad and Tobago; Tunisia; Turkey; Tuvalu; United Kingdom; United States; Uruguay; Vanuatu; Venezuela, Bolivarian Republic of; Viet Nam; Yemen
Biology and Ecology
Sperm whales generally feed at depth in search of their preferred prey which consists of a variety of squid species, including the giant squid, Architeuthis. Female sperm whales almost exclusively eat squid while males have been documented to prey on bottom dwelling fish, including sharks, rays, cod and hake1. Sperm whales typically dive to an average depth of 800 meters for 50 minutes in search of food. Their bodies are uniquely adapted for this deep diving, with features such as high concentrations of the oxygen-carrying protein, myoglobin, in their muscles3, and a collapsible rib cage that allows their lungs to be compressed during deep dives.
Social structure, reproduction and growth
Sperm whales form highly stable social groups based around related females and their offspring. These groups tend to live in open ocean areas, and are occasionally visited by males who range widely across the oceans. Calves are born after a 14-16 month gestation period, and stay with their mothers for many years. A calf will start to eat solid foods by the age of 1 year, but may continue suckling for several more years until the next calf is born. Young males will leave their female family unit when 4-21 years old, and will often join a ‘bachelor herd’ with other males of approximately the same age and size. These bachelor herds are observed in colder waters toward the poles. Females, however, stay with their family unit of 4-21 individuals and help to care for young in the group until they are mature enough to have their own calves. Like killer whales, they are one of the only mammal species other than humans, in which females continue to live and play a role in family/social groups after they have stopped producing calves. Fully mature males return to the warmer waters where the females are found in order to mate, sometimes spending only a few minutes or hours with a group before moving on again1,4.
Research, threats and conservation status
Individual sperm whales can be recognised over time through crenulations and scarring on their dorsal fins and tail flukes. These photos are used to monitor individuals’ movements over time, estimate local population size and understand the social structure and population dynamics of the groups that are studied5-7.
Genetic sampling and the use of tags to monitor whales’ diving behaviour have been very important for understanding of sperm whale behaviour and populations 8-10 . More information about research techniques used to study whales and dolphins can be found here.
Killer whales have been observed attacking sperm whale pods, and large sharks are also thought to be potential predators of calves. Sperm whales in some parts of the world have a unique response to attacks, gathering into a ‘marguerite’ or wagon wheel formation – in which all members of the group position themselves with their heads in the centre and their tails facing outward like the spokes of a wheel. They then fend off attack by slashing their tails back and forth. Sometimes a vulnerable calf or injured whale is positioned at the centre of the formation1,11.
Sperm whales face a number of threats today, including entanglement in fishing gear12-14, ingestion of fishing gear and marine debris15,16, and ship strikes17-22. The latter is thought to be one of the main drivers of sperm whale population decline in the Mediterranean18,20,21, and a major threat to survival of sperm whales in the Canary islands17,19.
Sperm whales were historically heavily hunted, and today are globally designated as Vulnerable on the IUCN Red List of Threatened Species2. The genetically distinct Mediterranean subpopulation, however, is considered Endangered, due to the fact that there are estimated to be fewer than 2,500 individuals and the persistent threats of ship strikes and entanglement throughout the area23. Sperm whales are listed on Appendix 1 of the Convention on Migratory Species (CMS).
Sperm whales and whale watching
Because of their predominantly offshore distribution, there are only a few places in the world where sperm whales can be regularly viewed and form the focus of whale watching tourism. These places include Kaikura, New Zealand, where deep fjords provide good habitat for sperm whales close to shore24, and where a number of studies are looking into the possible short-and long term effects of whale watching on the whales25,26; the Azores (Portugal) and the Canary Islands, (Spain), where there are also concerns about the sustainability of whale watching and pressure from vessel traffic27. For sperm whales, as well as all other species, it is important that guidelines are followed to limit the impacts of whale watching on the whales’ long term welfare and survival.
Afficher / Masquer les références
- Whitehead, H., Sperm Whale, Physeter macrocephalus, in Encyclopedia of Marine Mammals, W. Perrin, B. Wursig, and J.G.M. Thewissen, Editors. 2009, Elsevier: San Francisco. p. 1091-1097.
- Taylor, B.L., et al., Physeter macrocephalus in IUCN Red List of Threatened Species. 2008, http://www.iucnredlist.org/details/41755/0 Downloaded on 9 October 2017.
- Mirceta, S., et al., Evolution of Mammalian Diving Capacity Traced by Myoglobin Net Surface Charge. Science, 2013. 340(6138).
- Whitehead, H., The behaviour of mature male sperm whales on the Galapagos breeding grounds. Can J Zool, 1993. 71.
- Childerhouse, S. and S.M. Dawson, Stability of fluke marks in individual photoidentification of male sperm whales at Kaikoura, New Zealand. 1996. p. 447-451.
- Frantzis, A., P. Alexiadou, and K.C. Gkikopoulou, Sperm whale occurrence, site fidelity and population structure along the Hellenic Trench (Greece, Mediterranean Sea). Aquatic Conservation: Marine and Freshwater Ecosystems, 2014. 24(S1): p. 83-102.
- Gero, S. and H. Whitehead, Critical Decline of the Eastern Caribbean Sperm Whale Population. PLoS ONE, 2016. 11(10): p. e0162019.
- Engelhaupt, D., et al., Female philopatry in coastal basins and male dispersion across the North Atlantic in a highly mobile marine species, the sperm whale (Physeter macrocephalus). Molecular Ecology, 2009. 18(20): p. 4193-4205.
- Whitehead, H., Gene–culture coevolution in whales and dolphins. Proceedings of the National Academy of Sciences, 2017. 114(30): p. 7814-7821.
- Watkins, W.A., et al., Sperm whale dives tracked by radio tag telemetry. Marine Mammal Science, 2002. 18(1): p. 55-68.
- Ponnampalam, L., No Danger in Sight? An Observation of Sperm Whales (Physeter macrocephalus) in Marguerite Formation off Muscat, Sultanate of Oman. Aquatic Mammals, 2016. 42(2): p. 162-167.
- Di Natale, A. and G. Notarbartolo-di-Seiara, A review of the passive fishing nets and trap fisheries in the Mediterranean Sea and of the cetacean bycatch. 1994. p. 189-202.
- García-Godos, I., et al., Entanglements of large cetaceans in Peru: few records but high risk. Pacific Science, 2013. 67(4): p. 523-532.
- Haase, B. and F. Felix, A note on the incidental mortality of sperm whales (Physeter macrocephalus) in Ecuador, in Gillnets and Cetaceans, W.F. Perrin, G. Donovan, P., and J. Barlow, Editors. 1994, Report of the International Whaling Commission: Cambridge, U.K. p. 481-484.
- de Stephanis, R., et al., As main meal for sperm whales: Plastics debris. Marine Pollution Bulletin, 2013. 69: p. 206–214.
- Jacobsen, J.K., L. Massey, and F. Gulland, Fatal ingestion of floating net debris by two sperm whales (Physeter macrocephalus). Marine Pollution Bulletin, 2010. 60: p. 765–767.
- Carrillo, M. and F. Ritter, Increasing numbers of ship strikes in the Canary Islands: proposals for immediate action to reduce risk of vesselwhale collisions. Journal of Cetacean Research and Management, 2010. 11(2): p. 131–138.
- De Stephanis, R. and E. Urquiola, Collisions between ships and cetaceans in Spain. Document presented to the Scientific Committee of the International Whaling Commission SC/58/BC5, 2006.
- Fais, A., et al., Abundance and Distribution of Sperm Whales in the Canary Islands: Can Sperm Whales in the Archipelago Sustain the Current Level of Ship-Strike Mortalities? PLoS ONE, 2016. 11(3): p. e0150660.
- Frantzis, A., et al., Update on sperm whale ship strike risk in the Hellenic Trench, Greece. Report presented to the Scientific Committee, of the International Whaling Commission 2015. SC/66a/HIM06(Sand Diego, California): p. 6.
- Rendell, L. and A. Frantzis, Mediterranean Sperm Whales, Physeter macrocephalus: The Precarious State of a Lost Tribe, in Advances in Marine Biology. 2016, Academic Press.
- Laist, D.W., et al., Collisions between ships and whales. Marine Mammal Science, 2001. 17(1): p. 35-75.
- Notabartolo di Sciara, G., et al., Physeter macrocephalus (Mediterranean subpopulation), in IUCN Red List of Threatened Species. 2012, http://www.iucnredlist.org/details/16370739/0 Downloaded on 9 October 2017.
- Dawson, S.M., Distribution, abundance and population structure of Sperm Whales at Kaikoura 1996, WWF. p. 2-32.
- Gordon, J., et al., Effects of whale-watching vessels on the surface and underwater acoustic behaviour of sperm whales off Kaikoura, New Zealand, in Science & Research Series No. 52. 1992, Department of Conservation: Wellington, New Zealand.
- Richter, C., S. Dawson, and E. Slooten, Impacts of commercial whale watching on male sperm whales at Kaikoura, New Zealand. Marine Mammal Science, 2006. 22(1): p. 46-63.
- Ritter, F., Abundance, distribution and behaviour of cetaceans off La Gomera (Canary Islands) and their interaction with whale-watching boats and swimmers, in Master's Thesis. University of Bremen. Bremen, Germany. 1996.