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OUGD403: Echolocation Research

For the newspaper article, I'm doing additional research on Echolocation. Whales are fairly renown for using echolocation, dubbed as whale songs. These are not usually detected by human ears, but Noc, the Beluga Whale, speaks several octaves lower than most other whales, detectable by human ears.

"Echolocation, also called biosonar, is the biological sonar used by several kinds of animals. 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 and for foraging (or hunting) in various environments. Some blind humans have learned to find their way using clicks produced by a device or the mouth"

"Beluga whales have been called "canaries of the sea", and anecdotes of their capacity for mimicry have been reported in the past.[2] For example, the first two scientists to study the calls of wild Belugas wrote that "occasionally the calls would suggest a crowd of children shouting in the distance", and keepers at the Vancouver Aquarium said that a 15-year-old Beluga named "Lagosi" was able to speak his own name.[4] However, NOC's human-like calls were the first of their kind to be recorded.[5]
NOC's vocalizations were recorded and studied by a team of biologists from the National Marine Mammal Foundation (NMMF) led by Sam Ridgway. In 1984, Ridgway and others at the NMMF began to hear peculiar sounds coming from the whale and dolphin enclosure. They were reminiscent of two people talking in the distance, the words just beyond the limit of comprehension.[3] Later, a diver working in the enclosure came to the surface after he heard someone cry "out, out, out!"[1] After he asked his colleagues "Who told me to get out?", they realized it had been NOC.[5] They immediately began to record the sounds and reward him for the behavior, teaching him to make them on command. Eventually, they installed a pressure sensor in his nasal cavity to better understand the mechanism by which the sounds were produced.[5]
According to Ridgway, "They were definitely unlike usual sounds for a [beluga], and similar to human voices in rhythm and acoustic spectrum."[1] Unlike humans who use their larynx to produce sounds, whales use their nasal tract. Data gathered from the pressure sensors indicated that NOC was using his nasal tract as well, although he altered his normal vocal mechanics.[3] In particular, he over-inflated his vestibular sac, which is normally used to prevent water from entering the lungs.[5]
NOC's vocalizations were described during a conference in 1985, and in a 2012 paper by Ridgway et al. which appeared in Current Biology" 

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