Stejneger's beaked whale
| Stejneger's beaked whale | |
|---|---|
| |
| Specimen at the Pratt Museum, Homer, Alaska[1] | |
| Scientific classification | |
| Kingdom Information | |
| Kingdom | Animalia |
| Subkingdom | Bilateria |
| Phylum Information | |
| Phylum | Chordata |
| Sub-phylum | Vertebrata |
| Infraphylum | Gnathostomata |
| Class Information | |
| Superclass | Tetrapoda |
| Class | Mammalia |
| Sub-class | Theriiformes |
| Infra-class | Holotheria |
| Order Information | |
| Superorder | Preptotheria |
| Order | Cetacea |
| Sub-order | Odontoceti |
| Family Information | |
| Superfamily | Ziphioidea |
| Family | Ziphiidae |
| Sub-family | Hyperoodontinae |
| Genus Information | |
| Genus | Mesoplodon |
| Species Information | |
| Species | M. stejnegeri |
| Population statistics | |
| Population | Unknown (2020 est.; see below)[2] |
| Conservation status | Near threatened[3] |
Stejneger's or Bering Sea beaked whale (Mesoplodon stejnegeri) is a species of whale of the family Ziphiidae, and found in the waters of the North Pacific Ocean and Bering Sea. The species name was given in honor of the American zoologist Leonard H. Steineger (1851-1943), who collected the first specimens in 1883.
Description
Stejneger's beaked whale is small in comparison with other beaked whales. Females are 18 feet in length, and the slightly-smaller males are 17 feet 6 inches. The body is torpedo-shaped, the head is narrow and the beak is relatively short. The lower jaw, larger than the upper, has a central bulge on either side of which sits a large, triangular tooth, as long fore to aft as it is tall, that is visible even when the mouth is closed. Stejneger beaked whales are colored dark gray on the upper side, with the underside, neck, and beak lighter in color. They have strikingly small fins, but the tail fluke is wide and, like most beaked whales, does not have a center notch.
Range and habitat
Stejneger's beaked whale is found in the north Pacific Ocean and the southern half of the Bering Sea, keeping roughly along the edge of the continental shelf of North America and Asia, and migrating as far south as northern Japan and the waters off southern California; these migrations, it should be noted, are based upon scars left by the cookie-cutter shark (Isistius sp.), a species which lives in warmer waters[4][5]. They live in small schools of two to six, sometimes up to fifteen animals. The animals in schools swim so close together that they touch, and they also dive together. The diet of these whales consists mainly of squid and fish such as salmon.
Threats
No firm estimate has been given as to overall numbers of this species, but guesses have been made via the number of stranded individuals in Japan during the period of 1999-2011[6]; these and current strandings were suspected to have been caused by ingestion of man-made materials, decompression sickness, and the operation of military sonar systems. Drifting entanglements at sea, such as abandoned lines and gill nets, have also taken a toll[7].
References
- ↑ These animals are extremely rare to film or recover. According to the original photographer, this animal was found washed ashore in 1977, the victim of a gunshot wound.
- ↑ https://www.iucnredlist.org/species/13252/50367496#population
- ↑ https://www.iucnredlist.org/species/13252/50367496
- ↑ https://www.farout.org.nz/images/farout/documents/members-other-publications/Dwyer%20Visser%20(2011)%20cookie%20cutter%20shark%20bites%20on%20cetaceans.pdf
- ↑ https://www.researchgate.net/publication/229765019_Biological_observations_on_Stejneger%27s_beaked_whale_Mesoplodon_stejnegeri_from_strandings_on_Adak_Island_Alaska
- ↑ https://journals.sagepub.com/doi/abs/10.1177/0300985820914079?journalCode=vetb
- ↑ https://www.iucnredlist.org/species/13252/50367496#threats
