sperm whale
| sperm whale | ||||||||||||
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A sperm whale with her calf near Mauritius |
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| Physeter | ||||||||||||
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| Physeter macrocephalus | ||||||||||||
| Linnaeus , 1758 |
The sperm whale ( Physeter macrocephalus , syn .: Physeter catodon ) is a whale from the suborder of the toothed whale (Odontoceti) widespread in all oceans . It is the only large whale among the toothed whales . Sperm whales feed primarily on squid ; the bulls can dive to depths of more than 1,000 meters.
The closest relatives of the sperm whale are the dwarf sperm whales (genus Kogia ), with which it (according to some views) forms the family of the sperm whales (Physeteridae).
designation
The German term "sperm whale" refers to the head of the whale, which protrudes like a pot ( Low German Pott ). The English name "Sperm Whale" and the name of a so-called Spermaceti organ can be traced back to the appearance and consistency of the whale rat , reminiscent of sperm . The scientific names Physeter macrocephalus (horns - big head) and Physeter catodon (horns - teeth below) are used. The names were described by Linnaeus ( Carl von Linné ) in the 10th edition of his Systema Naturae in 1758 and declared synonymous by Thomas in 1911 . So far, however, neither of the two names has finally prevailed.
Another name for the sperm whale, preferred in many European languages in corresponding variants, but rarely used in German, is Kaschelott, a Germanization of the French. cachalot , which in turn presumably goes back to an old Romance word for toothed .
features
Male sperm whales are significantly larger and heavier than females, and their sexual dimorphism is the largest among marine mammals. Large bulls reach lengths of over 20 meters and weights of over 50 tons, making them the largest toothed animals on earth. However, some specimens seem to be able to grow even larger, as shown by some trophies from the time when sperm whales were still hunted on a large scale. A pair of teeth over 30 cm long, for example, which are in the collection of the New Bedford Whaling Museum , suggest that the whale in question may have been well over 20 meters long and weighed over 100 tons. The females reach up to 12 m and a weight of 15 tons.
The enormous head, which is almost rectangular in silhouette and can make up to a third of the total length, is characteristic of the species. The brain weighs up to 9.5 kg, making it the heaviest in the entire animal kingdom. The eyes are relatively small. The fragile lower jaw is also very narrow compared to the size of the entire skull and has 40 to 60 teeth, some of which are more than 20 cm long. Another special feature of the sperm whale is that only the conical teeth of the lower jaw can be used and they snap into the corresponding horn sheaths in the upper jaw, while the teeth of the upper jaw normally remain invisible. This raises the question of hunting and eating behavior, which has not yet been clarified. However, teeth and jaws do not seem to play a major role in the hunt, because well-fed sperm whales were found whose jaws were completely deformed and not suitable for holding prey. Sperm whales can make unusually loud sounds. In this could sound pressure level are measured in excess of 230 dB, which may be suitable, according to one theory to stun prey or disorient (for comparison, a cannon shot has about 150 dB).
The skin of the whales is usually furrowed lengthways and often scarred on the head, the color is reminiscent of light marble . The dorsal hump or dorsal fin is low and varies greatly. A series of humps or spikes extends from the dorsal fin to the tail fluke. It has short, stubby pectoral fins ( flippers ). The fluke is shaped like two adjacent right-angled triangles, slightly rounded at the top and deeply indented in the middle.
The only, S-shaped breathing hole is at the top of the head, asymmetrically on the left side, which creates an oblique blow .
The huge head of a sperm whale is largely filled by the so-called spermaceti organ and the junk melon . These are completely filled with spermaceti and can weigh several tons. The organ is connected to two air sacs that merge into the nasal passages. The thesis that Spermaceti increases the density through solidification at low temperatures and thus reduces the buoyancy of a diving sperm whale, is considered refuted by measurements on diving animals. The temperature-dependent, peculiar consistency of the Spermaceti gave cause for confusion with sperm .
Other theories about the purpose of this organ are common:
- The spermaceti organ could give the head of male sperm whales more stability and strength to favor their use as battering rams in combat. Cases are known and in some cases also documented in which a sperm whale apparently deliberately, deliberately and repeatedly used its forehead as a battering ram against ships, at least one of which resulted in the sinking of a 300-ton whaling sailor (the Essex in 1820) (→ literature entry: records of Owen Chase , Moby-Dick by Herman Melville ; in Jules Verne's 20,000 Leagues under the sea , the incident is mentioned).
- It could play a role in emptying the lungs before diving and absorbs nitrogen when the water pressure is high .
- It could serve to focus sound for the purpose of echolocation .
distribution and habitat
Sperm whales are found in all oceans . The males in particular are known to migrate long distances, sometimes reaching into the polar regions and marginal seas . The associations of females and young animals, on the other hand, are concentrated in the tropics and subtropics and avoid surface temperatures below 15 ° C. No other organism is known that exhibits a comparable spatial separation between sexually mature males and females.
A sperm whale was first sighted in the Baltic Sea in August 2004, but it is far too shallow for the deep diver to survive and offers hardly any suitable food. More typical are small groups (“schools”) of mostly young bulls who mistakenly end up in the North Sea on their annual migrations back to warmer waters from the direction of the Arctic . It is believed that these animals , coming from the Norwegian coast, fail to swim around Great Britain as a natural barrier in time.
Sperm whales can be found all year round, for example in the Azores , off Portugal and an estimated several hundred in the Mediterranean , for example in the area of the Greek coast at the Hellenic Rift with a population of around 200 animals.
Way of life
Movement and Orientation
Along with Cuvier's beaked whales and the southern elephant seal , sperm whales are among the deepest diving marine mammals. Depths of 350 m are apparently regularly exceeded. On average, males dive longer and deeper than females and also advance to extreme depths of over 1,000 m. The discovery of fish in sperm whale stomachs, which can only be found at a depth of over 3,000 m, makes it certain that even these depths can be reached. The duration of a dive can be 20 to 100 minutes.
Sperm whales have ribs that give way when the water pressure increases, which allows them to withstand this enormous pressure. We know, however, that when diving they restrict their metabolism to a minimum and only supply blood to the most important organs, i.e. the heart, brain and spinal cord, and that they can store a large amount of oxygen in their blood and muscles . Your blood also has 50% more hemoglobin than humans. During the dive, your heart beats only half as fast as on the surface.
The normal migration speed of the whales is 5–10 km / h, especially in danger they can accelerate up to 20 km / h.
Sperm whales use only one form of echolocation for orientation and foraging . The vocalizations have little in common with the songs of some baleen whales . Rather, it is a series of clicks that have a lower frequency than that of the dolphins . The sequence of the click sounds is individually different, the animals can produce about six of them per second.
nutrition
The diet of sperm whales consists mainly of squid caught at great depths. Up to 10 m tall specimens of the giant squid were found in the stomachs of dead animals. There are also traces of giant squid suckers on the bodies of sperm whales. This could lead to the conclusion that whales and squids are fighting each other in the deep sea. However, the exact circumstances are still completely unexplored. In addition to cuttlefish, sperm whales also feed to a small extent on medium-sized fish (e.g. cod , tuna and monkfish , smaller sharks), sometimes even on larger crustaceans . For the bulls, fish seem to make up a larger proportion of the diet, especially in the more northerly areas.
A bull needs about one and a half tons of food per day.
Some researchers try to draw conclusions about the migrations of sperm whales from the food. Whilst whole squids are rarely found when examining stomach contents, the chitinous jaws ("beaks") remain largely undigested. On the one hand, these provide more precise information about the sperm whale's diet. On the other hand, researchers can use the specific beaks of squids in the stomachs of captured sperm whales to partially understand the migration routes of these whales. If, for example, the beak of a colossal squid native to Antarctica is found in the stomach of a captured sperm whale, conclusions can be drawn about the migrations of the sperm whale through the habitat of the squids.
Sleep behavior
Sperm whales have been seen floating vertically upside down in the water 7% of the time in the wild. It is believed that this is sleep with both sides of the brain. So far, only half-brain sleep has been detected in captive animals, as is the case with other dolphins and whales.
Social behavior and reproduction
Females form social associations with their young. They live in groups of about fifteen to twenty animals; before the age of whaling, these schools are said to have been much larger and comprised several hundred animals. Sexually mature males leave the association and form groups for their part, isolated or older bulls are also traveling alone, they are called "rovers". Although sperm whales are not known to interact with other species, communities of whales made up of individual animals from other species of marine mammals have been observed. These are apparently not only tolerated, but treated similarly to their own young animals. The reasons for this behavior are still unclear.
In the breeding season, the males come back to the associations of the females. Here one male maintains a harem of around ten females. The social behavior during this time has not yet been fully clarified. Some observations suggest that rival males fight for the right to lead a harem, while others seem to demonstrate the establishment of a hierarchy in which several males share a harem.
The exact gestation period for the cows is not known, but it is estimated at 10 to 17 months. Young animals weigh around 1000 kg at birth and are between four and five and a half meters tall. They are suckled for one to two years before they can eat on their own. There is a big difference in sexual maturity, which females reach at around 9 years of age and males only at 25. The growth rings on the teeth suggest that sperm whales can live to be at least 70 years old.
Enemies
It is believed that adult, healthy sperm whale bulls have no enemies other than humans. However, decrepit or injured animals and rarely groups of females and calves can fall victim to killer whales or larger sharks . In the event of an attack, sperm whale associations are known to encircle their calves or weakened animals for protection, or to form a kind of phalanx . It was also observed that otherwise solitary bulls joined groups of females and young animals in distress for support; it is assumed that conspecifics in the vicinity can be alarmed acoustically. In the case of attacks on schools and smaller groups by orcas, in particular, it has been observed that sperm whales, similar to other large whales, behave in an incomprehensibly passive manner and use an all-or-none tactic that appears to be maximally altruistic. Individual animals consciously expose themselves to attacks in order to block them on smaller, weaker or already wounded conspecifics, or to lead them back into the protective circle of the others; the group basically stays together, even if flight seems a better option from the point of view of the individual. This can lead to a whole school “sacrificing” itself, the evolutionary advantage of this behavior is the subject of discussion.
Hazard and protection
Due to past hunting , the populations are still so low that the sperm whale is considered endangered. Estimates of the population vary from 1 million animals to only around 360,000 specimens.
Whalers in the past have reported very large sperm whales. In the report of the sinking of the whaling ship Essex by a sperm whale attack in 1820 , Owen Chase estimated the length of this sperm whale to be 85 feet, around 25 meters. Since the ship itself was of this order of magnitude, this estimate can be considered realistic.
Was sought after next to Tran from the bacon ( Blubber ), especially the left in the head spermaceti and ambergris from the intestines. While ambergris found buyers mainly in the cosmetics industry, Spermaceti was processed into whale oil and whale rat.
Over 20,000 sperm whales were killed annually in the 1960s and 1970s. The whaling of the years 1987–2002 by members of the International Convention for the Regulation of Whaling is given as a total of 206 animals.
Another threat is the swallowing of plastic waste . Deep-sea cables are also a danger for the animals, as they can also be close to the ground and get caught in the cables and drown. Accidents of this type occurred at a depth of over 1,000 m.
The World Conservation Union IUCN has the sperm whale in the Red List of Threatened Species as endangered ( Vulnerable ) from.
The Bonn Convention CMS, supported by the UNEP environmental program, places this whale species under protection as a migratory species in Appendix I and Appendix II. As a regional agreement of the Bonn Convention, the ACCOBAMS convention for the protection of the whales of the Black Sea, the Mediterranean Sea and the adjacent Atlantic zones was signed on November 24, 1996. In Annex 1 of this contract, among other things, the catching of sperm whales and other whale species is prohibited and the establishment of special protected areas is required.
The sperm whale enjoys protection from free trade by placing a trade ban on its species through the Washington Convention on CITES, Appendix I. This attitude is adopted in the EU Species Protection Regulation (EC) No. 338/97 Appendix A. In the Bern Convention of the European Council of November 19, 1979, the sperm whale is listed under Appendix II as an animal species to be strictly protected. The European Union takes into account the protection concept in Directive 92/43 / EEC or Fauna-Flora-Habitat Directive . The Federal Republic of Germany designated the sperm whale in the Federal Nature Conservation Act as a species to be strictly protected.
Between January and February 2016, 29 sperm whales stranded in the southern North Sea , 13 of them off the Schleswig-Holstein coast, making it the largest sperm whale death ever recorded off Schleswig-Holstein.
Sperm whales in literature
Although sperm whales have some characteristics that are otherwise atypical for whales, they and their silhouette are a popular motif for exemplary representation and allusion and sometimes as prototypical whales par excellence. The sperm whale also found its way into world literature through Herman Melville's novel Moby-Dick . The title goes back to a whale that received a lot of public attention in the 19th century: " Mocha Dick " was a male sperm whale with more gray than brown skin and a white scar on its head. It owes its name to his first meeting with whalers around 1810 near the island of Mocha off the Chilean coast. In 1859 he was shot by a Swedish whaler. Melville changed the name of the whale to "Moby" and interwoven in his novel the events of the sinking of the whaler Essex according to the records of his then chief mate Owen Chase .
An Antarctic group of reef rocks was named after this family of animals named Catodon Rocks .
In Jules Verne's science fiction novel 20,000 Leagues Under the Sea , the sperm whale is described by Captain Nemo as a cruel, noxious breed whose extermination is justified. In a meeting there is a massacre in which numerous animals are killed.
Web links
- Physeter macrocephalus on marinespecies.org
- Physeter macrocephalus in the endangered Red List species the IUCN 2009. Posted by: BL Taylor, R. Baird, J. Barlow, SM Dawson, J. Ford, JG Mead, G. Notarbartolo di Sciara, P. Wade & RL Pitman, 2008 Retrieved January 11, 2010.
- Website of the association Pottwale eV
Individual evidence
- ↑ Pottfisch in Economic Encyclopedia (1773-1858) by Johann Georg Krünitz
- ↑ Kaschelott on duden.de; accessed on May 2, 2015
- ^ Entry in the Oxford English Dictionary , 2nd edition, 1989
- ^ A b Nathaniel Philbrick : In the Heart of the Sea: The Tragedy of the Whaleship Essex. Penguin Books, 2001, ISBN 978-1-101-22157-0 (reprint).
- ↑ Spectrum of Science Sperm Whale Acoustics : Moby Dicks Boombox , accessed on February 2, 2016, original in issue 09/2015, p. 10 ff.
- ^ William F. Perrin, Bernd Würsing, JGM Thewissen: Encyclopedia of Marine Mammals. Second Edition, Academic Press, 2009, ISBN 978-0-12-373553-9 , p. 1091.
- ↑ PJ O Miller, MP Johnson, PL Tyack, EA Terray: Swimming gaits, passive drag and buoyancy of diving sperm whales Physeter macrocephalus. In: Journal of Experimental Biology . 2004, 207, 1953-1967.
- ↑ Hal Whitehead: Sperm Whales in Ocean Ecosystems , p. 325, in: Estes, James A. et al. (Ed.): Whales, Whaling, and Ocean Ecosystems. University of California Press, 2006, ISBN 978-0-520-24884-7 .
- ↑ Lost sperm whale sighted in the Baltic Sea Article in the FAZ of August 13, 2004; Retrieved May 3, 2015
- ↑ Endangered marine giants OceanCare , accessed August 13, 2016.
- ↑ a b The Secret Life of the Sperm Whales ( Memento of April 14, 2009 in the Internet Archive ), Das Erste , June 18, 2003.
- ↑ a b c Information sheet on sperm whales (PDF; 243 kB) of the State Office for Coastal Protection, National Park and Marine Protection Schleswig-Holstein; accessed on May 9, 2015.
- ↑ Malcolm Clarke: Cephalopoda in the Diet of Sperm Whales of the Southern Hemisphere .
- ^ Karen Evans, Mark A. Hindell: The diet of sperm whales (Physeter macrocephalus) in southern Australian waters . In: ICES Journal of Marine Science . tape 61 , no. 8 , January 1, 2004, ISSN 1054-3139 , p. 1313–1329 , doi : 10.1016 / j.icesjms.2004.07.026 ( oup.com [accessed November 30, 2019]).
- ↑ Richard Ellis: Giant Octopus of the Deep Sea . Ed .: Richard Ellis. 1st edition. Heel Verlag, ISBN 3-89365-876-9 , pp. 254 .
- ↑ Matt Kaplan: Researchers sneak up on sleeping whales. In: nature.com. February 21, 2008, accessed May 25, 2019 .
- ^ Sarah Gibbens: Why These Whales Are 'Standing' In the Ocean. In: nationalgeographic.com. May 5, 2018, accessed May 25, 2019 .
- ↑ Sperm whales adopt crippled dolphin Report on scinexx.de, accessed on May 2, 2015
- ↑ Michael Friedrich: Behavioral Research: Klick Klick-Klick , Greenpeace Magazine Issue 1.05, accessed on February 22, 2019.
- ↑ Günther Behrmann: Age determination of the sperm whales (Physetericeti), based on waste products of the Chernobyl reactor in April 1986 , in: Lebensraum "Meer", issue 24 (PDF; 2.2 MB), accessed on February 22, 2019.
- ↑ Randall R. Reeves, Joel Berger, Philipp J. Clapham: Killer Whales as Predators of Large Baleen Whales and Sperm Whales , p. 174 in: Estes, James A. et al. (Ed.): Whales, Whaling, and Ocean Ecosystems. University of California Press, 2006, ISBN 978-0-520-24884-7 .
- ^ Robert L. Pitman, Lisa T. Ballance, Susan J. Chivers, Sarah L. Mesnick: Killer Whale Predation on Sperm Whales: Observations and Implications . in Marine Mammal Science 17 (3): 494-507, July 2001.
- ↑ Emil Abderhalden : Biochemisches Handlexikon. 3rd volume, Springer, 1911, ISBN 978-3-642-51194-3 , pp. 215, 223 f.
- ↑ Gray whale dies bringing us a message - with stomach full of plastic trash report on Realnews24.com of November 5, 2013 (English); accessed on May 2, 2015.
- ↑ Sperm whale with 100 kg of garbage in the stomach Schweizerbauer.ch of December 2, 2019; accessed on December 2, 2019.
- ↑ Sperm whales: stranding in the North Sea. In: Whale and Dolphin Conservation (WDC). Retrieved February 22, 2019 .
- ↑ Chronology: The great sperm whale death. In: ndr.de. February 6, 2016, accessed August 5, 2016 .