Whales:

Giants of the ocean

The whale is one of the largest and most majestic animals to ever inhabit our planet. Would you believe that it was originally a four-legged land dwelling mammal which evolved into a sea-dwelling mammal millions of years ago?

A long,long time ago, the oceans were filled with these animals, who like us, breathe oxygen, give birth to live offspring and have a complex family and social structure. However, as is the case with most animals, humans killed them for food and blubber (fat) and drove this species to the brink of extinction.Today, even though most countries in the world have banned whaling, this species is still endangered.

Now, let's check out some interesting facts about these gigantic creatures the family of which , as most of you may be aware of by now, has a species that holds the world title as the largest animal on Planet Earth!It is none other than the blue whale.

The term "whale" is a common name given by scientists for a mammal under the order of cetacea. This term is mainly used to describe all members of the whale family; however we most often leave out the dolphin and porpoise families in this general categorisation.

There are two main types of cetaceans: They are the Toothed Whales (Odontoceti) which include orca(killer whales) and sperm whales and also the Baleen Whales (Mysticeti) including blue whales and humpback whales among others. The toothed whales are usually smaller and there are around 66 species under this main category. Baleen Whales are usually larger and have two blowholes instead of one like the Toothed Whales.

There are about ten species of Baleen Whales that can be found today. The Baleen Whales use long strips of baleen that serve as teeth for them, to strain the seawater when they are feeding.This is where their name originated from.

Every physical feature of the whale has undergone changes so that it is now perfectly adapted to an aquatic life. Modifications in their systems allow them to dive up to depths of 4000 metres and stay underwater for as long as an hour.Their bodies have a flawless shape in which all sensory organs are compressed and therefore reduce the drag when swimming, allowing them to swim up to speeds of 35km/h, propelled by powerful lateral tail flukes(up and down tail movements).

Their senses of taste and smell have all but disappeared. They have extremely poor vision; however, to compensate for all this they have the most acute and well developed sense of hearing of all living creatures.

Whales can produce and receive sounds--bleeps, whistles, clicks, moans, and complex "songs"of a range from lower than our lowest hearing frequency up to thirteen times more than our upper hearing frequency. The normal and lower ranges are used to communicate over long distances underwater, and the higher frequencies are used in sonar echolocation to determine location, identify objects, and find food,often in total darkness.

Like in most animals where sound passes through the outer ear to the middle ear, in whales it is recieved from their throat, from which it passes through a low-impedance, fat-filled cavity, to the inner ear.

The largest whale, which is ofcourse the female blue whale, may grow up to 100 ft, weigh about 150 tons, and live to be a hundred!

Did you know that the most dangerous natural enemy of this huge animal is isactually a smallinner-ear parasite? You may be surprised to learn that whales have also been discovered to have human illnesses such as ulcers, dental caries and even tonsillitis.

The whale brain is in actual size and by proportion, the largest and most complex brain of any animal, including humans. It weighs on average about five and a half times more than a human brain. Since it does not have any external technology or aid for recording, the whale uses its brain as a sort of memory file. It stores large amounts of detailed information regarding culture and environmental data. Experiments with smaller whales strongly indicate the ability to carry out plans made ahead of time, as well as powers of initiative and a well grounded reasoning and understanding of traditions and ethics.

These huge sea mammals are generally classified as predators. Their food varies from minute plankton to sometimes very large fish. The orca sometimes eats other sea mammals and also other whales, but the latter happens rarely.

The humpback and the blue whales eat only in Arctic waters, and feed mostly on krill. They swallow these with large amounts of sea water, and excrete it through their baleen plates, whilst retaining the krill.

Whales do not drink water, but absorb it indirectly from their food.Whales, unlike most animals, have to decide when to breathe. It is a conscious effort for them when they do, and this is called "˜The Blow".

It is possible to spot a whale from far away because a spray of water shoots up from their blow-holes. Their breath rushes out at speeds of up to 450km/h and can go up to five metres.The spray apparently has a very fishy smell and also contains sufficient oil content.

Have you ever wondered if these animals in the sea sleep the way we humans and most other animals do? Well, the answer is interesting because sleep is necessary for all animals and even whales need to take a break. But, it impossible for a whale to sleep for too long because there is a danger of them drowning. Because of this it is believed that whales only sleep with one hemisphere of the brain resting at a time, and thereby are never really asleep. Reports suggest that often whales sleep with one eye open.Well, try sleeping like a whale..

Although many mammals sleep for many hours a day, the whale often gets only enough sleeping time to function.

Whale communication is one of the most interesting areas of study. Some whales communicate with each other using lyrical sounds, which are more commonly known as "whale songs".

These sounds can be extremely loud (depending on the species); sperm whales have only been heard making clicks, because toothed whales (Odontoceti) use echolocation and can be heard for many miles. They can generate about 20,000 acoustic watts of sound at 163 decibels.

Females give birth to a single calf. Nursing time is more than one year in many species, and this forms a strong bond between the cow and the calf. When it comes to reproduction females are known to reach a reproductive age only at seven to ten years. This means that only a few whales are born per year. It also ensures a higher survival rate for the calves. Whales do not usually have a fixed partner, and normally has several during the reproductive season. Whale mamas give birth to their young tail first, which minimises and all but prevents the chances of drowning. The young are fed by the mother squirting milk into their mouths. Whales are known to teach and learn, as well as cooperate, scheme, and even seem to grieve very much like humans do.

-Shalindri Perera

Facts and pix: Internet

Whales in Sri Lanka:

You need not travel far to see these gigantic mammals because they are found in the Indian Ocean too close to our little island. In fact a high concentration of blue whales and sperm whales has been spotted in the seas off Dondra Head along the deep south coast of Sri Lanka during the months of January to April..

According to marine biologists, the deep sea off Dondra Head is one of the best locations to watch whales in Sri Lanka because of its close proximity to the coast

Commercial whale watching in Sri Lanka was first mooted in the 1980s following documentation of whale sightings in the Trincomalee bay by marine biologists of the research vessel called the Tulip. They found out that blue whales and sperm whales were coming into the Trincomalee harbour using a submarine canyon. The Voyage of Odyssey, the second research vessel to do research on marine life off Sri Lanka's southern coast in 2003, had also documented whale sightings. Whales of Trincomalee had also featured in the award winning film "Whales weep not", the first underwater filming of Sperm whales in their natural habitat. Marine biologists believe that some of the whales in our waters could be resident whales while others are migrants crossing over to the Arabian Sea from the Bay of Bengal. On March 15, 2008 a killer whale, an orca, was sopotted and photographed by an amateur photographer about three nautical miles off Kalpitiya on the West Coast.

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Fast facts

* Sperm whales, the largest carnivore mammals, mostly feed on squid and octopus in the deep sea bed.

* Whales are very large animals that live in the ocean, but they are not fish!

* They live in large groups called herds.

* As whales do not have gills,they cannot breathe under water. They must come up to the surface of the water to get air. The air is breathed in and out through their blowhole which is on their back.

* Baleen whales are also called toothless whales.There are many kinds of baleen whales, including blue, bowhead, Bryde's, fin, gray, humpback, minke, right and sei.

* Whales migrate further than any other animal

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