WiLD Blog

This time, whales have beat humas in the diving sport, new research shows that beaked whales can dive up to 6,230 feet under water for 85 minutes.

Web page Livescience.com reported in October 2006 that whales may be experiencing dificulties when diving up from the deep of the ocean, as they dive up, bubbles of gas gather within their brain o f these mamals for comming to fast from the ocean depths; this is not a practice for them, one of the reasons why they go so deep into the ocean is food; there, whales can catch big amounts of mollusks and survive for days; although the brain damage that these beautiful animals suffer is painfull, it is believed that they find relief exposing themselves on the beaches after a long dive for food.

“The reason for this is that once the lungs have collapsed under pressure, gas does not diffuse from the lungs into the blood, lung collapse is thought to occur shallower than 330 feet, so deeper parts of the dive do not increase the risk of decompression problems.” said Peter Tyack, a senior scientist in the Woods Hole Oceanographic Institution.

posted by jose Lopez 

The love song of a humpback whale sounds magnificently free-flowing and improvised to the casual human listener.

But fresh mathematical analysis of shows there are complex grammatical rules. Using syntax, the whales combine sounds into phrases, which they further weave into hours-long melodies packed with information.

Although the researchers say these songs don’t meet the linguistic rigor necessary for a true language, this is the first evidence that animals other than humans use a hierarchical structure of communication. Whales have also been found to sing in dialects.

The study is detailed online in the March issue of the Journal of the Acoustical Society of America.

Whales rely on sound, which travels four times faster in water than in air.During mating season, which lasts six months, all humpback males sing the same song to woo the ladies. Over time, the group’s song becomes progressively more complex, although researchers don’t know quite why.

Presumably, as one whale finds mating success by tinkering with the song style, the rest of the guys imitate it to better their chances, said study co-author Ryuji Suzuki, a Howard Hughes Medical Institute predoctoral fellow.

The researchers used information theory-the mathematical study of data encoding and transmission-to pick apart the whales’ songs. It turns out all those moans, cries, and chirps convey significant amounts of information.

Suzuki and his colleagues designed a computer program to break down each element of the songs, collected from humpbacks in Hawaii, and assign a symbol to each. Analyzing the complexity, redundancy, and predictability of a string of signals produces an unbiased assessment of the information they might contain.

“It’s a good way to study humpback whale songs, because we don’t know what they mean and we want to quantify their complexity and the information content across the seasons,” Suzuki told LiveScience.

He then asked human test subjects, with no prior knowledge of whale songs or particular expertise in grammar, to classify each song according to the same criteria the computer used to break them up. Both the human characterizations and computer analyses indicate that whales communicate following rules for grammatical arrangement.

Information content

Humpbacks repeat short and long phrases multiple times to sing long songs-the longest known lasts 20 hours. They also sing in multiple layers, or scales, of repetition called periodicities. A short scale consists of six units, whereas a longer one contains 180 to 400.

Despite these differences, the average amount of information carried by each song was about constant regardless of length, Suzuki said.

The amount of information expressed, however, can’t compare to human speech. Whale songs generate less than one bit of information per second, while people convey about 10 bits of information per word spoken.

“Although whale song is nothing like human language, I wouldn’t be surprised if some marine mammals have the ability to communicate in a complex way,” Suzuki said. “Given that the underwater environment is very different from our world, it is not surprising that they would communicate in rather a different way from land mammals.”

 http://www.livescience.com/

posted by: jose Lopez

photo source: http://www.shellbackdon.com/whale-watch.htm