Monday, 7 April 2008

Whales' Lifes---Please Protect Them

On Nov. 18, a fleet of four Japanese vessels left Shimonoseki harbor in Western Japan to begin its five-month whale hunt in the Antarctic Ocean. This time, however, the whalers are planning what's expected to be its largest hunt in decades; along with about 850 minke and 50 finback whales, the fleet says it plans to harpoon as many as 50 humpback whales for the first time since hunting the endangered species was banned in 1963.

From Jonah’s whale to Moby Dick, man has created and perpetuated many myths about the mysterious whale. And the biggest rumor of all is true.

Whales are indisputably the largest animals to ever inhabit the earth. Blue whales are even bigger than dinosaurs.

How big are they? That’s hard to know, since whales are shy about jumping on the bathroom scales. Historically, that scale was on a whaling vessel, where weighing was done in a hurry to make room for the next victim. Weights weren’t and aren’t always accurate, though it’s much easier to estimate a whale’s length. Blues are the longest at around 30 mtrs (100 ft) long.
Blue whales are found in Antarctica, along with Fin, Humpback, Killer, Minke, Sei, and Right whales. These whales belong to the Order called Cetacea – which means large sea creature – and cetaceans are divided into two sub-orders: baleen whales (Mysticeti) and toothed whales (Odontoceti).

All whales are carnivores, but the different species prefer slightly different diets. Blue whales are baleen whales, which means that the biggest whale actually eats the smallest animals.

Baleen Whales

Baleen whales mostly eat zooplankton, such as krill, by filtering massive amounts of these tiny creatures through comb-like plates that hang from their upper jaws. These whales have huge skulls that are specially adapted to this food-filtering lifestyle. A baleen whale’s skull can take up a third of its body length.

Each species varies some in the look, feel and specific function of its baleen. Coarse baleen that is spread wider apart filters out larger prey, and finer baleen that is closer together filters out smaller prey. The baleen itself is keratin, which isn’t really bone at all but the stuff from which fingernails and hooves are made. Whalers apparently didn’t care about the details, since they hunted “whalebone” (baleen) and sold it to manufacture human essentials such as umbrella ribs, corsets, and brushes.

Baleen whales are further divided into rorquals, which have grooves that run the length of their throats and expand during feeding, and Right whales, which feature extremely long baleen designed for dining while swimming.

Most baleen whales are rorquals. They include Minkes, Sei whales, Fin whales, Blues and Humpbacks. Right whales had the misfortune of being the “right” whale to hunt in the 19th and early 20th centuries.

Baleen whales have two breathing holes, and they can actually breathe at the same time they eat. This is a big deal if they’re also nursing calves.

Female baleens are bigger than the males, sometimes by up to 2 mtrs (6 feet). The females apparently need the extra size since they fast during winter migrations from feeding grounds to breeding grounds while suckling their calves.

Toothed Whales

Of 90 whale species, 76 are toothed and only 11 are baleen. Dolphins and porpoises, Orcas, and even Moby Dick (a sperm whale) are of the toothed variety.

Toothed whales have sharp teeth that are designed to grab individual prey animals. That means toothed whales hunt bigger prey than baleen whales do. Their diets include fish, squid, birds, mammals, and anything else they can catch. Orcas are called Killer whales for a reason. They hunt warm-blooded animals like penguins, seals, and even other whales.

Other than Sperm whales, most toothed whales are smaller and more agile than baleens.
Toothed whales use echolocation to hunt, much like bats do. Echolocation is the practice of emitting sounds that bounce off objects, thereby providing a mental picture of the animal’s environment. Whales emit clicks that echo back any change in their surroundings.

Toothed whales have only one blow-hole, unlike baleen whales. Most Odontocets have a fatty lens at the front of their heads called a melon. This melon might help focus and transmit echolocation sounds that are generated inside the skull.

Males are bigger than females, but both sexes tend to have battle scars from minor and major disagreements with others. Orcas can be sexed and identified by the shape, size, and saddle (white patch) of their dorsal fins.

Of course, some species are identified by their tails. Something we’re grateful is not true for us humans.

Whales are warm-blooded animals that must “breach” to the surface to breathe air. Most mammals breathe through their mouths as well as their nostrils, but whales have airways – called breathing holes – that are separate from their mouths.

Unlike our nostrils, breathing holes are on top of whales’ heads. They can breathe while staying mostly submerged, and some even breathe while eating. Whales hold their breath until they decide to expel it, which they do in sudden bursts called “blows.” They’re voluntary breathers, not involuntary breathers like the rest of us. Baleen whales have two blow holes, and toothed whales have one.

Whales also differ from other mammals in that they give birth in water. Calves must be guided to the surface for their first breath of air.

Many baleen whales migrate long distances from feeding areas to breeding grounds. Antarctic humpbacks travel some of the longest distances. They feed in waters off the Western Antarctic Peninsula, and then swim north to a breeding area on the equator near Columbia.

Whales have boneless horizontal tail fins, or rear flippers. The whale propels forward by moving these “flukes” up and down.

To help with deep diving, whales have a high level of myoglobin in their muscles. This red pigment is like hemoglobin in that it stores oxygen in the muscles. The oxygen is replaced when the whale surfaces.

Whales maintain their core body temperatures with the help of a heavy dose of blubber that can comprise up to 30-40% of their total body weight. They also have a specialized heat-exchange system that keeps their vital organs warm in cold water or conversely cools off their surface area when whales overheat.

Bigger whale species collect external parasites such as barnacles, diatoms (algae), and whale lice. These creatures hide in the nooks and crannies of a whale’s skin where they won’t be washed away, feeding on the whale’s shedding skin and sometimes on its flesh wounds. Breaching is thought to help remove these parasites and dead skin.

Breaching might also be associated with taking a look around, avoiding predators or collisions with other whales and boats, or just to say howdy to the neighbors.

Whale TalkWhales are experts in underwater communication. Sound is important to whales because it transmits approximately 4-1/2 times faster in water than it does in air. Plus, it’s harder to see under water.

Southern right whales might breach to communicate with each other. Their thumping sounds can be heard more than one km (2/3 ml) away.

Sound is not only used to communicate, but it’s also used for echolocation. Toothed whales use higher frequencies than baleens do. These higher frequencies travel shorter distances than the lower frequencies, which may travel hundreds or thousands of kilometers/miles.

Fin and Blue whales voice low rumblings that are outside of human hearing, and dolphins talk in high whistles and clicks.

Humpbacks are known to “sing” complex songs of interesting snorts, chirps, yips, yaps, and whoos that might last 10 to 15 minutes. It takes a student of music theory to decipher the different phrases and themes that compose these haunting whale tunes.

But for a humpback it’s a simple matter of love. Only the male humpbacks sing, and they most likely croon to attract females. The moral to the story is: If you want a mate, make sure you’re singing from the right songbook… and please try to stay on pitch for the sake of your fellow humpbacks.

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