Baleen whale

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Baleen whales Fossil range: latest Eocene - Recent
Humpback Whale breaching
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Cetacea Suborder: Mysticeti Cope, 1891
Families
Balaenidae Balaenopteridae Eschrichtiidae Neobalaenidae

Baleen

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.

Baleen whales are generally larger than toothed whales, and females are larger than males. This group comprises the largest living animal species, the Blue Whale. Baleen whales have two blowholes, causing a V-shaped blow.

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 mystax, which means "moustache".

[edit] Feeding

Baleen whales do not have teeth; instead they have baleen in the upper jaw. They engulf sea water containing crustaceans, then close their mouth and create internal pressure by raising their tongue toward the palate to push the water out through the 'comb' of baleen plates, trapping small ocean animals, especially krill and other plankton, inside.

This is called filter feeding, and is also used by flamingos. Even though individually the crustaceans are minuscule, baleen whales take in an enormous volume of water containing them to maintain their survival.

There are several types of food-finding methods:

• Gulpers (swallowers): alternate between swimming and opening their mouths, e.g. Blue Whales, Pygmy Blue Whales, Fin Whales, Bryde's Whales, Humpback Whales, and Minke Whales.
• Skimmers: predominantly have their mouths open while swimming, e.g. right whales, Pygmy Right Whales, and Bowhead Whales
• Benthic feeders: Gray Whales
• Combined: Sei Whales are both swallowers and skimmers

[edit] Behaviour

[edit] Movement

Baleen whales live in all oceans. All species travel seasonally. They spend the summer in cold waters in high latitudes, where they feed. In autumn they migrate to warmer waters to mate and give birth. Except in their feeding grounds, baleen whales eat little or fast for months. The Gray Whale travels the longest migratory route of all mammals.

[edit] 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, and was identified in three separate sightings.

[edit] Vocalizations

See also: Whale song

In contrast to toothed whales, baleen whales are unlikely to echo-locate. Instead they are able to produce high volume sounds in the infrasonic range. The calls of the largest whales can be heard several hundred kilometres away. Unique are the songs of the Humpback Whales, consisting of complex sequences that may slowly evolve over years. They are probably used for courting.

[edit] Human interaction

In the 19th and early 20th centuries, baleen whales were hunted 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.

[edit] Evolution of Baleen whales

See also: Evolution of Cetaceans

Early baleen whales first appeared as far back as Early Oligocene, or perhaps the latest Eocene (39-29 mya). Early forms did not (or little) have baleen, but still had teeth obtained from their ancestors. Among them was Janjucetus, a baleen whale with sharp teeth that hunted fishes, squid, and large prey such as sharks and probably dolphin-like cetaceans. This hints 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 to eat small fishes or other creatures. They probably evolved from teeth to baleen for food/water filtering.

[edit] Taxonomic classification

• ORDER CETACEA

[edit] See also

Cetaceans Portal

• Baleen
• Toothed whale
• Cetacea