Animal echolocationEcholocation, also called bio sonar, is a biological sonar used by several animal species. Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation, foraging, and hunting in various environments. Echolocating animals include mammals, most notably Laurasiatheria, especially odontocetes (toothed whales) and some bat species, and also, using simpler forms, species in other groups such as shrews.
Whale oilWhale oil is oil obtained from the blubber of whales. Oil from the bowhead whale was sometimes known as train-oil, which comes from the Dutch word traan ("tear drop"). Sperm oil, a special kind of oil obtained from the head cavities of sperm whales, differs chemically from ordinary whale oil: it is composed mostly of liquid wax. Its properties and applications differ from those of regular whale oil, and it was sold for a higher price. Emerging industrial societies used whale oil in oil lamps and to make soap.
InfrasoundInfrasound, sometimes referred to as low frequency sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz, as defined by the ANSI/ASA S1.1-2013 standard). Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. The ear is the primary organ for sensing low sound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body.
