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||WHALE ANATOMY AND BEHAVIOR
- SIGHT - Cetaceans' vision is not extremely important to them except when they're at or near the surface. Deep beneath the sea, the water is dark and murky. Also, light waves don't travel very well or very far in water. These facts lessen the importance of vision in ocean-dwelling animals.
- HEARING AND ECHOLOCATION - Sound is carried much more efficiently through water than through air. Dolphins and toothed whales have excellent hearing and use echolocation (also known as SONAR or bio-SONAR) to sense objects. They make short, intense, broad-band pulses of ultra-sonic sound which bounce off objects near it. The animal "hears" the objects in its environment, creating an acoustical picture. Baleen whales don't use sophisticated echolocation, probably because they don't have to stalk prey. They probably have some some less sophisticated form of echolocation.
In echolocation, a high-pitched sound (usually clicks) is sent out by the whale. The sound bounces off the object and some returns to the whale. The whale interprets this returning echo to determine the object's shape, direction, distance, and texture. Bats and some other marine mammals also use echolocation.
A toothed whale's echolocation starts with a series of low-frequency clicks (called a train) produced by the animal. This train passes through the melon of the whale (a fat-filled organ in the head of the toothed whale that focuses the sound wave). The train of clicks is focused into a beam that bounces off objects and reflects (echoss) back to the whale.
The echoed sound waves are received in the fat-filled cavities of the lower jaw-bone. These sounds are conducted through the bone to the ear and the brain, where the location of the object is interpreted. The whale can determine the distance to an object, its size, shape, the speed that the object is travelling, and its texture.
- SMELL - Cetaceans have a very limited or non-existent sense of smell. The olfactory bulb in the brain is primary in the sense of smell, but these olfactory bulbs are reduced in baleen whales and are absent in toothed whales (toothed whales have no sense of smell at all).
- TASTE - Research on the existence whales' taste buds is mixed and contradictory. Experiments have shown that dolphins do have a sense of taste.
- TOUCH - Cetacean skin is very sensitive to touch. Also, most Cetaceans have stubble-like whiskers on their snouts called vibrissae. These vibrissae are thought to be an additional tactile indicator (like a cat's whiskers).
- MAGNETISM - Whales may use the magnetic field of the Earth for navigation purposes on their long migrations across the oceans. It is not known how they sense magnetism. Many mass whale beaching occur at place where there in an anomaly (abnormality) in the Earth's magnetic field, perhaps confusing the whales.
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