Whales
Wikipedia tells us this about
whales:
Whale is the common name for various marine mammals of the order Catacea.
The term whale sometimes refers to all cetaceans, but more often it excludes
the dolphins and porpoises, which belong to the suborder Odontoceti (toothed whales).
This suborder includes the sperm whale, killer whale, and beluga whale. The other
cetacean suborder, Mysticeti (baleen whales), comprises filter feeders who eat small
organisms caught by straining seawater through a comblike structure found in the mouth
called baleen. This suborder includes the blue whale, the humpback whale, the bowhead
whale and the minke whale. All cetaceans have forelimbs modified as fins, a tail with
horizontal flukes, and nasal opeings (blowholes) on top of the head.
But I like whales because they are:
- Huge!
- Friendly
- Can hold their breath for a long time
Whale Anatomy
There are some key parts to a whale's anatomy that I think are interesting.
-
Blowhole:
Whales breathe via blowholes; baleen whales have two and
toothed whales have one. These are located on the top of the head, allowing the animal
to remain almost completely submerged while breathing. Breathing involves expelling
stale air (which is warm and moist), as well as some mucus and excess water from the
blowhole, forming an upward, steamy spout, followed by inhaling fresh air into the lungs.
Spout shapes differ among species, which facilitates identification.
-
Ears:
The whale ear has specific adaptations to the marine
environment. In humans, the middle ear works as an impedance equalizer between the
outside air's low impedance and the cochlear fluid's high impedance. In aquatic
mammals, such as whales, however, there is no great difference between the outer and
inner environments. Instead of sound passing throught he outer ear to the middle ear,
whales receive sound through the throat, from which it passes through a low-impedance
fat-filled cavity to the inner ear. The whale ear is acoustically isolated from the
skull by air-filled sinus pockets, which allow for greater directional hearing
underwater.
Pictures!
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Whale jumping out of water
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Killer whale jumping out of water
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