Whale Watching Around The World Part 14
Those searching for a more intimate view of whales should consider paddling their own individual kayaks. Particularly fruitful destinations for kayaking are Alaska's Inside Passage, the Puget Sound region of Washington and British Columbia, the St. Lawrence River and its tributaries in Quebec, and Mexico's Sea of Cortez, places that generally have calm waters and abundant beaches, coves, inlets and bays. Outfitters offer a variety of options: guided tours, transport to and from sites with your own kayak or rented equipment, kayaking instruction, and trip-planning advice.
Whales produce the loudest sustained sounds in the animal kingdom. The moan of a blue whale can last up to 30 seconds at 188 decibels. By comparison, a 747 jet generates about 110 decibels of perceived sound at take-off.
Scientists know little about the meaning of whale sounds. Contrary to a popular misconception, researchers have not isolated anything close to a language in whale songs. But they have identified the repetitive sounds that comprise songs. To the untrained ear, whale songs sound random; to experienced researchers, however, they are long melodic patterns, repeated over and over. To the whales themselves, the songs may be a sexual come-on or a way to maintain space between individuals or establish a position in the social order.
Maritime lore is filled with stories of sailors hearing siren songs and mysterious sounds at sea, but it wasn't until the 1950s that these underwater noises were first recorded by the military. Now underwater recordings are relatively easy to make using a hydrophone, a specialized underwater microphone, and an ordinary tape recorder and receiver. Many whale-watching tours now carry hydrophones so that passengers can listen to nearby whales. This adds an entirely new and fascinating dimension to the experience. Often, the intervals between sighting the animals on the surface are filled with acoustic activity, some of it far more bizarre than the whale recordings many of us may have already heard.
Name That Tune
Researchers place whale sounds into two categories: social sounds and song. Humpback whale song is composed of organized sequences of grunts, chirps, whistles, and wails known as themes. Themes can last from a few minutes to half an hour, and the songs may contain several themes. Humpback songs are sung exclusively by bulls in tropical mating and calving grounds in winter. All males sing the same song, but over seasons, the pattern of notes changes gradually and the males all learn the revised song. Biologists have distinguished several geographically isolated populations of humpbacks with their own local song sequences. Humpbacks in the North Pacific, for example, sing a different song from those in the Caribbean.
Biologists have also recorded whale songs and fragments of song themes in the colder, northern waters where whales feed in summer. The separate stocks mingle in the feeding grounds, and it is possible that the new season's song is developed and passed among males while feeding. Prior to this discovery, scientists had few theories about how whales managed to all learn the same song.