
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.
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".
Anatomy
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.
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, and was identified in three separate sightings.
Vocalization
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.
Importance to humans
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.
Evolutionary history
Early baleen whales first appeared as far back as Early
Oligocene, or perhaps the latest
Eocene (39-29 million years ago). Early baleen whales did not have (or had very little) 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 and eventually to feed by filtering.
Taxonomic classification
★ 'ORDER
CETACEA'
★
See also
★
Baleen
★
Toothed whale
★
Cetacea
Bibliography
References
External links
★
Whale and Dolphin Conservation Society (WDCS)