History of Our Gentle Giants
WHALE EVOLUTION
All whales, dolphins and porpoises belong to the same order of mammals called the
cetaceans. Like other mammals, they breathe air with lungs, have warm blood, bear their
young living, and suckle their young with milk from mammary glands. They are completely
different however from most mammals, in they have no long legs and no fur, except for the
few hairs found on their heads.
Evidence has been found to support that cetaceans started evolving at least 45 or
50 million years ago from land mammals that had hind legs. Similarities in the number
and molecular structure of chromosomes indicated that all cetaceans shared a common
ancestor at that time. Studies suggested that the cetaceans are descendants of ancient
cattle or perhaps the hippopotamus.
In the case of cetaceans the tail became the main source of locomotion. Wide flukes
made of connective tissues and tendons developed on the sides of the tail for propulsion
and steering. The cetacean tail beats up and down, instead of side to side as in fish,
mainly because of the muscles used are basically the same as those used by the ancestral
mammal for flexing backbone up and down during running.
WHALES & MAN
The reason that they are endangered is man. From the beginning, we as a race have hunted and poisoned them almost to extinction. Whales have always been a part of man's culture. Their abundance in the north, along with their friendly and slow moving manner may have spurred hunters on to discover a way to capture and kill a whale. With small boats and harpoons, they set out and the rest is history. Modern whaling soon developed, using mechanized harpoons and high speed ships that increased whaling activitites. Whaling soon spread, exploiting the Antarctic feeding grounds and southern bases in Georgia and the Shetlands. In 1925, land based whaling moved onto factory ship operations. It became a major industry, picked up by many countries.
The regulation of whaling was not originaly sparked by the need to 'save the whales.' It was because the markets were swamped with whale products, driving the prices down. In 1931, the League of Nations attempted to control the situation. They decided that it was better to catch one large whale than several small ones. This caused problems for the populations of the blue whales and other large whales. Rules were set, making a hunting season. It was illegal to hunt mothers with calves, closing certain areas and limiting the numbers of certain species that were allowed to be hunted. This did little over the years to protect them.
Not until the late 60's, early 70's did there develop a desire to protect the whales. Groups like Greenpeace began to fight to 'save the whales.' Presently, there are laws to protect whales, and their numbers are slowly increasing. Legal hunting still occurs now, but only with licenses that are given to people who's culture depends on the whale. Over the years, cetacean's have been driven to the point of extinction. Many species, like the gray whale, have only recently been given the chance to exit the endangered species list. Still, with everything we have done to right our wrongs, the numbers are not increasing as they should. Part of this is due to pollution. Spills like the Exxon disaster, toxic waste, and litter like garbage have posed a threat to all animals, but in the ocean, mainly to cetaceans.
Throughout history, whales and people have been linked with myths, lengends,
literature, art, music, and commerce. Up until recently, people were interested
mainly in the products that the whales' body could produce. Studies were
being done to understand our gentle giants better. The apparently high intelligence
and trainablility of some dolphins brought out a kinder light to the public that these
giant creatures that are portrayed in myths and literature as dangerous and killers were anything but.
The recording of their sounds and songs were soon sold to the public, with films, books,
and articles that stimulated public attention as well. Little is really known of
these creatures, because some of the species are currently critically endangered.
It is urgent that we all learn as much as we can about them.
photo 2 & 3 c/o The Natural History of Whales and Dolphins
photo 1 c/o Whales and Other Mammals
Andrea Vanessa & Erica @ the Advanced Technologies Academy