Whales
Wikipedia tells us this about
whales:
Whale is the common name for various marine mammals of the Cetacea.
The term whale sometimes refers to all cetaceans, but more often it excludes
dolphins and porpoises, which belong to the suborder Odontoceti (toothed whales).
This suborder includes the sperm whale, killer whale, pilot 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 openings
(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 through the 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!
|
|
Whale jumping out of water
|
Killer whale jumping out of water
|