About Baleen Whales
According to the Sea World website, baleen whales appeared approximately 30 million years ago. The species of whale takes its name from its oral structure, which is made not of teeth, but of keratin plates which allow the mammals to filter tiny food particles from the water. Keratin is the substance that is also found in hair and fingernails. Ten species of the baleen exist, including the humpback whale, blue whale, gray whale and right whale.
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Size
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Baleen whales are some of the largest creatures on the plant. Their girth keeps the baleen whales from being preyed on by other sea creatures. The blue whale, with a length of 90 feet, is the longest baleen whale and is the largest known animal on earth. A blue whale can tip the scales at 138,000 lbs. and the heaviest blue whale ever weighed came in at 338,000 lbs., according to the Sea World website. At a length of 21 feet long, the pygmy right whale is the smallest of the baleen whales. Females of the same baleen whales species are often 5 percent bigger than their male counterparts.
Reproduction
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Whales give birth to live young called calves. A female often will only give birth to one calf at a time, often during the migration process. The gestation period can last up to 16 months and a newborn calf will often weigh about 5 percent of the body weight of its mother. Upon birth, a calf is capable of swimming. During the migration season, a female may mate with several males to ensure fertilization. Females usually give birth about every two to four years.
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Life Span
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As baleen whales do not possess teeth, determining an exact age of the creatures is difficult. Researchers are able to make a determination of the age of baleen whales by examining their ear plugs as well as growth patterns on baleen plates. Estimates, according to the Sea World website, of the life of a blue whale is about 90 years, while fin whales may live up to a century.
Endangered Species
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The baleen whales were once hunted heavily by whalers, who used the whale oil for lighting, lubrication and heating. Whale oil can also be used in making soaps, textiles and ropes. Hunters also would kill the whales for their baleen, which could be used to manufacture corsets, umbrellas, brushes, skirt hoops along with whips and fishing rods. Due to overhunting, several species of the baleen whale are endangered species including the blue, bowhead, fin, humpback, right and sei whales.
Communication
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Baleen whales are able to communicate with each other even though the creatures possess no vocal cords. The sounds of the whale are capable of traveling for miles under the sea. Sounds are created at low frequencies, often less than 5,000 Hz. The creature's sounds are often composed of grunts, moans, chirps and whistles. The humpbacks are known for their songs, which are produced by the males. Songs can last more than 30 minutes long and may indicate location and status, according to the Sea World website. Baleen whales also communicate through body language. Smacking pectoral flippers in the water may signify that a whale is excited or angry.
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References
- Photo Credit whale tail diving image by Xavier MARCHANT from Fotolia.com
