Beaked whales

from Wikipedia, the free encyclopedia
Beaked whales
Mesoplodon bidens on a Faroe Islands postage stamp

Mesoplodon bidens on a Faroe Islands postage stamp

Systematics
Class : Mammals (mammalia)
Subclass : Higher mammals (Eutheria)
Superordinate : Laurasiatheria
Order : Whales (cetacea)
Subordination : Toothed whales (Odontoceti)
Family : Beaked whales
Scientific name
Ziphiidae
Gray , 1850
Genera

The beaked whales (Ziphiidae; also obsolete pointed-snouted dolphins ) are a family of toothed whales . Although they comprise 19 species, making them the second most species-rich whale family after the dolphins , very little is known about them. This has to do with the fact that they are extremely rarely found near the coast. Many of the species were only recently described.

anatomy

Beaked whales are named after their elongated snout, which distinguishes them from other larger whales. In some species the head goes straight into this snout like a dolphin, but in others the snout is distinctly separated from the head like a bird's beak. The size of the beaked whale is 4 to 13 m.

Usually beaked whales have two or four teeth in the lower jaw while the upper jaw is completely toothless. Only the shepherd whale has functional, small teeth in the upper jaw. In many species, however, only the males have a pair of tusk-like protruding teeth. These are used as weapons in battles with one another, as evidenced by the scars on their bodies. In the genus of the two-toothed whale , these tusks can take on bizarre shapes, for example in the Layard whale ( Mesoplodon layardii ), whose teeth are bent inwards over the beak and restrict its opening.

Way of life

Beaked whales are deep-sea creatures that are common in all oceans. They feed mainly on squids ( teutophagy ), which they prey in the deep sea by creating a negative pressure with their pronounced hyoid bone, with which the squids are literally sucked in. In the hunt for squid, they undertake diving expeditions of remarkable duration and depth. For the Cuvier's beaked whale off the coast of California, diving depths of 2992 m and diving times of 137.5 minutes are documented. Blainville's beaked whales can also dive up to 1,200 meters. These dives are made possible by a particularly high content of the oxygen- transporting protein myoglobin in the muscle cells .

Little is known about the behavior of many species because the animals are rarely seen at sea. Small groups are mostly observed. The main sources of information, however, are the dead bodies of stranded whales . The duck whales and black whales have been researched best , which is related to the pursuit of these species by whalers .

Influence of man

Apart from these genera, the direct influence of humans on the beaked whale population is insignificant. However, the proliferation of toxic chemicals in the ocean and littering with plastic waste pose a growing threat.

A study published in 2009 supports the theory that beaked whales are more vulnerable to the use of sonar devices than other marine mammals. Startled by the sonar, the whales emerge too quickly. The consequence of this is decompression sickness , which can lead to death.

evolution

Beaked whales appear to have no close relatives among toothed whales. They have been fossilized since the Miocene and are therefore a very old family of toothed whales.

classification

Blainville's beaked whale ( Mesoplodon densirostris )

New species are still being described all the time. The Perrin beaked whale was only described in 2002. The Longman's beaked whale, which is sometimes carried under the ambiguous name “Pacific beaked whale”, was known for a long time only from two skulls washed up in Australia and East Africa; In 2002 a hitherto unknown whale was washed up on the Japanese coast in which it was believed that this species, which had been a mystery for a long time, was recognized. Although it is still questioned by some authorities, most zoologists believe that it is the first complete specimen of the Longman's beaked whale ever found.

credentials

  1. ^ Gregory S. Schorr, Erin A. Falcone et al. a .: First Long-Term Behavioral Records from Cuvier's Beaked Whales (Ziphius cavirostris) Reveal Record-Breaking Dives. In: PLoS ONE. 9, 2014, p. E92633, doi : 10.1371 / journal.pone.0092633 .
  2. ↑ Jonathan Amos: Beaked whale is deep-dive champion. BBC, March 26, 2014, accessed March 26, 2014 .
  3. ↑ Peter L. Tyack, Mark Johnson, Natacha Aguilar Soto, Albert Sturlese, Peter T. Madsen: Extreme diving of beaked whales . In: Journal of Experimental Biology . tape 209 , no. 21 , 2006, ISSN  0022-0949 , p. 4238-4253 , doi : 10.1242 / jeb.02505 .
  4. ↑ Martin Schäfer: Record in extreme diving goes to the beaked whales. Wissenschaft.de, October 23, 2006 . For sperm whales , however, even deeper dives are documented.
  5. ↑ Audrey McAvoy: Sonar could make whales appear too quickly . In: Spiegel online. June 11, 2009. Retrieved July 6, 2009.
  6. ↑ Michael McCarthy: Navy sonar blamed for death of beaked whales found washed up in the Hebrides . In: independent.co.uk. April 7, 2009, Retrieved July 6, 2009.
  7. ↑ SK Hooker, RW Baird, A. Fahlman: Could beaked whales get the bends? Effect of diving behavior and physiology on modeled gas exchange for three species: Ziphius cavirostris, Mesoplodon densirostris and Hyperoodon ampullatus . In: Respiratory Physiology & Neurobiology . tape 167 , no. 3 , July 2009, p. 235 , doi : 10.1016 / year or 2009.04.023 .
  8. ↑ Merel L. Dalebout, C. Scott Baker, Debbie Steel, Kirsten Thompson, Kelly M. Robertson, Susan J. Chivers, William F. Perrin, Manori Goonatilake, R. Charles Anderson, James G. Mead, Charles W. Potter, Lisa Thompson, Danielle Jupiter, Tadasu K. Yamada. Resurrection of Mesoplodon hotaula Deraniyagala 1963: A new species of beaked whale in the tropical Indo-Pacific. Marine Mammal Science, 2014; DOI: 10.1111 / mms.12113
  9. ↑ Tadasu K. Yamada, Shino Kitamura, Syuiti Abe, Yuko Tajima, Ayaka Matsuda, James G. Mead and Takashi F. Matsuishi. 2019. Description of A New Species of Beaked Whale (Berardius) found in the North Pacific. Scientific Reports. 9: 12723. nature.com/articles/s41598-019-46703-w

Movie

On the quiet trail of the beaked whales , TV documentary, 2010, 44 min., Production: Bayerischer Rundfunk . Documentation about a research expedition in the Atlantic: a team of marine biologists tries to track down the shy beaked whales using acoustic methods and to research their behavior.

Web links

Commons : Beaked Whales  - Collection of images, videos and audio files

Spektrum.de : The most mysterious whales in the world's oceans November 14, 2018