Hobbies And Interests
Dolphins
A dolphin is a small, aquatic, fish-like mammal, belonging to the scientific families Delphinidae (ocean dwellers) and Platanistidae (river dwellers). Some authorities cite that dolphins are closely related to whales. However, most authorities state that dolphins are actually toothed whales. Because of these differences, some experts attempt to clarify the distinctions by referring to these "true dolphins" according to their suborder name, Odontoceti/Odontocete. The name "dolphin" is also applied to an unrelated species of fish.
Bisonar
In dolphin echolocation, also called bisonar, two primary types of sounds are clicks and tone whistles. Echolocation clicks are produced in sequences that are either high- or low-frequency. Low-frequency clicks are associated with a generalized orientation of an object or environment; whereas high-frequency clicks pertain to "high-resolution" details. Pure tone whistles are thought to be used for finding prey and also for non-echolocate social purposes.
The farther the dolphin is from the desired object, the slower the echolocate click rate is. The dolphin can determine how far away the object is from the amount of time it takes for a sent click to return. As the gap in distance steadily decreases, the click rate increases to get more refined location information. Through echolocation, dolphins can also interpret an object's shape, size, speed of travel and some of its internal structures.
Transmission
Once an echo bounces back from an object, the principal area of the dolphin's sound reception lies within the lower jaw bones. From there, the sound is transmitted through the dolphin's inner ear and then transformed into a nerve impulse. That nerve impulse sends information to the brain.
Distance and Frequencies
Dolphins produce echolocate sound frequencies that are up to 10 times higher than those heard by humans. The duration of each click lasts up to 128 microseconds, and peak echolocate frequencies are approximately 40 to 130 kHz. A dolphin can detect a 1-inch object from 235 feet away.
General Communication
In addition to echolocate whistle and click sequences, dolphins produce other sounds such as pops, grunts, and squeaks meant for general communicative purposes. They have been observed conversing, such as in relaying instructions to one another. Also, each dolphin has its own signature whistle to identify itself, whereby even a dolphin calf is able to discern its mother's whistle. Because of their phenomenal level of intelligent dialogue, efforts have and are being made to learn dolphins' language and teach them human language.