Whale Communication
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Whale Communication
The study of whale communication, or whale sounds, is one of the most compelling parts of the study of whale biology. Most information found on this subject is found in recent years. Technology in the past twenty years has increased the ability for researchers to understand these strange sounds made by these amazing creatures. Researchers have found more information in the last twenty years than they have since the beginning of research on whales initially started. This is due to technology and new and improved ways to study these animals in their natural habitat rather than studying the deceased. Whale communication has a lot of history and a ton of information on different types of whales, sounds and also what this communication is leading to in future years.
During the twentieth century, whales were typically studied on the top of factory whaling ships. Examined and studied were blubber, stomach contents, gonads, and earwax layers. Researchers learned a lot from dead whales, but not a whole lot compared to what can be studied today. During World War II, much of whaling was put to a halt by German whaling chasers. Since these chasers were out to hunt allied submarines and big Japanese whaling ships, many whales were saved throughout the time of Pearl Harbor. Although many whales were saved, many were likely killed from the use of depth charges and bombs.
After the war, few biologists started to probe the ocean and actually listen to the sounds of whales themselves. A man named William Schevill was the first to make a hydrophone recording of cetaceans in the 1950s. In these recordings, William found sounds from all different types of sea mammals. These included sperm whales, blue whales, dolphins and seals. William also helped to defuse a debate between the U.S. and the Soviet Union during the Cold War. The American military had detected low frequency blips in the ocean and thought the Soviets might be using these sounds to find U.S. submarines. As it turns out, with the help of Schevill, these sounds were coming from fin whales, which produce trains of blips before surfacing. This is the first understanding of an odontocete whale sound production.
The production of sound for a whale is very different from the way humans speak. Although we can make similar sounds to whales, whales cannot make sounds similar to humans, or very many sounds at all in that matter. There are two different types of sound production found throughout cetaceans. Noises made by toothed whales, including dolphins, use the odontocete production of sound and baleen whales such as the largest whales like the Blue Whale use mysticete production.
Toothed whales do not make the long, low frequency sounds known as whale-songs. Instead these whales produce rapid bursts of high frequency clicks and whistles. Single clicks are usually used for echolocation whereas collections of clicks and whistles are used for communication. Throughout studies, researchers have found little information on the meaning of there communication. One researcher quotes “listening to a group of odontocetes is like listening to a bunch of children at a playground.” These sounds are created by air passing through a structure in the head called phonic lips. This is similar to the function of the human nasal cavity. When air passes through the passage, the phonic lip membranes are sucked together, causing the surrounding tissue to vibrate. These vibrations pass through the tissue of the head to the melon, which directs the sound into a beam of sound, which is useful in echolocation. With exception of the sperm whale, every toothed whale has two sets of phonic lips and is capable of two sounds at the same time. After air is passed through the phonic lips it enters the vestibular sac. The air is then recycled back into the lower part of the nasal complex, and is either ready to be used for sound or blown out of the blowhole. Phonic lips translated in French are “museau de singe,” which translates as “monkeys muzzle.” This is what the lips resemble. Studies found in 2004 show that these muzzle shaped lips in bottlenose dolphins can supply air into the palatopharyngeal sphincter, which enables the sound creation process to continue for as long as the dolphin is able to breathe.
Unlike the toothed whales, baleen whales, also known as mysticetes, do not have phonic lips. Instead, they have a larynx that plays the role of sound production. Scientists are still uncertain what mechanism actually creates the sound considering these animals lack vocal cords. However, researchers have found the process to sound production for mysticete whales. In complete opposition to how humans make sound, these whales do not have to exhale in order to make noise.