This MedLibrary.org supplementary page on Baleen whale is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
| Baleen whales Fossil range: latest Eocene - Recent |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
 Humpback Whale breaching
|
||||||||||
| Scientific classification | ||||||||||
|
||||||||||
| Diversity | ||||||||||
| Around 15 species; see list of cetaceans or below. | ||||||||||
| Families | ||||||||||
|
Balaenidae |
The baleen whales, also called whalebone whales or great whales, form the Mysticeti, one of two suborders of the Cetacea (whales, dolphins, and porpoises).
Baleen whales are characterized by having baleen plates for filtering food from water, rather than having teeth. This distinguishes them from the other suborder of cetaceans, the toothed whales or Odontoceti. Living Mysticeti species have teeth only during the embryonal phase. Fossil Mysticeti had teeth before baleen evolved.
The suborder contains four families and fourteen species. A list of species can be found below and at the Cetacea article. The scientific name derives from the Greek word mystidos, which means "unknowable".
Contents |
Anatomy
Baleen whales are generally larger than toothed whales, and females are larger than males. This group includes the largest living animal species, the blue whale.
Baleen whales have two blowholes, causing a V-shaped blow.
Ecology and life history
Behavioral ecology
Breaching
In spite of their enormous mass, baleen whales are able to leap completely out of the water. Particularly known for their acrobatics are the Humpback Whales, but other baleen whales also break through the water surface with their body or beat it loudly with their fins. The reason for these habits is not known for certain. Some believe that the male Baleen Whales try to show off to the females, to increase their mating success.
Importance to humans
From the 11th to the late 20th centuries, baleen whales were hunted commercially for their oil and baleen. Their oil can be made into margarine and cooking oils. Baleen was used to stiffen corsets, as parasol ribs, and to crease paper.
Evolutionary history
- See also: Evolution of Cetaceans
Early baleen whales first appeared as far back as Early Oligocene, or perhaps the latest Eocene (39-29 million years ago). Early baleen whales probably did not have extensive, if any, baleen, but did possess teeth inherited from their ancestors. The Oligocene species Aetiocetus cotylalveus is considered the evolutionary link between toothed and baleen whales. It was discovered by renowned fossil collector Douglas Emlong in 1964 near Seal Rock State Recreation Site, Oregon in a sandstone formation [1]. In the early 1990s, the species Janjucetus hunderi was discovered in Victoria, Australia by a surfer and was described in 2006 by E. M. G. Fitzgerald[2]. Janjucetus was a baleen whale with sharp teeth that hunted fish and squid as well as larger prey, potentially including sharks and dolphin-like cetaceans. These fossils hint that early baleen whales were predatory and eventually evolved into the gentler, toothless whales known today. The first baleened, toothless baleen whales probably appeared in the Early or Middle Miocene, from a toothed ancestor that adapted initially to eat small fishes or other creatures and eventually to feed solely by filtering.
Early forms of Baleen Whales may have also been able to echolocate.
Taxonomic classification
- ORDER CETACEA
- Suborder Mysticeti: Baleen Whales
- Family Balaenidae
- Genus Balaena
- Bowhead Whale, Balaena mysticetus
- Genus Eubalaena
- North Atlantic Right Whale, Eubalaena glacialis
- North Pacific Right Whale, Eubalaena japonica
- Southern Right Whale, Eubalaena australis
- Family Balaenopteridae: Rorquals
- Subfamily Balaenopterinae
- Genus Balaenoptera
- Fin Whale, Balaenoptera physalus
- Sei Whale, Balaenoptera borealis
- Bryde's Whale, Balaenoptera brydei
- Pygmy Bryde's Whale, (Eden's Whale) Balaenoptera edeni
- Blue Whale, Balaenoptera musculus
- Northern Minke Whale, Balaenoptera acutorostrata
- Southern Minke Whale, (Antarctic Minke Whale) Balaenoptera bonaerensis
- Balaenoptera omurai, discovery announced November 2003. No common name yet in usage
- Subfamily Megapterinae
- Genus Megaptera
- Humpback Whale, Megaptera novaeangliae
- † Genus Eobalaenoptera
- † Eobalaenoptera harrisoni, fossil species first discovered June 2004. No common name.
- Family Eschrichtiidae
- Genus Eschrichtius
- Gray Whale, Eschrichtius robustus
- † Family Janjucetidae
- † Genus Janjucetus
- Family Neobalaenidae
- Genus Caperea
- Pygmy Right Whale, Caperea marginata
- † Family Mammalodontidae
- † Genus Mammalodon
References
- ^ Wallace, D.R. (2007). Neptune's Ark: From Ichthyosaurs to Orcas. Berkeley ; London: University of California Press. ISBN 0-520-24322-6.
- ^ Fitzgerald, E. M. G. (2006). "A bizarre new toothed mysticete (Cetacea) from Australia and the early evolution of baleen whales". Proceedings of the Royal Society - 'B': Biological Sciences, 273 (1604): 2955–2963. doi:.
Wikipedia content modification information:
- This page was last modified on 4 September 2008, at 21:00.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Baleen whale".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.