Drawing On Science by Stephen Yaeger
Drawing On Science by Stephen Yaeger
Whales, those magnificent sea animals with a hole on top of their head, have always fascinated people throughout the centuries. Whales are classified as cetaceans (seh-TAY-shans) and include dolphins and porpoises.
The scientific study of whales, known as cetology (seh-TAH-logee), began in the fourth century BCE. But it is only since the eighteenth century that we have learned much about whales. Because of the difficulty of studying animals that live in the open ocean, cetology has had to rely almost entirely on the whaling industry.
Although whales have been hunted for many thousands of years it was not until the sixteenth century that whaling really took off. Willem Barents, a Dutch navigator, discovered Spitzbergen, a group of islands in the Arctic Ocean in 1596.
In 1607 Henry Hudson discovered the Bowhead whale near the islands. The Bowhead produces a great deal of oil and a whaling industry was established in the Spitzbergen area.
This was the beginning of the near extermination of creatures that took many millions of years to evolve. Whale hunting was at its peak during the eighteenth century; the Humpback, Sperm, Bowhead, and Right Whale populations were reduced to dangerous levels.
Beginning in the 1970s, with the help of the aqualung, modern research vessels, and waterproof cameras, and conservationists the study of whales has progressed. Today they are protected under international law, but Japan and Sweden are still hunting them.
Millions of years ago whales were land animals. A whale’s skeleton reveals bones near the tail that are vestigial (ves-TI-shee-al) limbs. This means that they are no longer used and the flippers look very much like our own hands with finger bones. This indicates that, at one time, the whale ancestor had limbs. Fossils of whale-like creatures show many changes that have taken place over millions of years. These changes include a whale’s torpedo-like appearance; its strong, flat flukes or tail fin; and its nose on top of its head. All of these things allowed whales to adapt to a watery environment.
Whales are mammals. They have hair, which, if you get close enough, can be seen as eyelashes and chin hair. They are homoeothermic (ho-me-o-THIR-mic) or warm-blooded and keep their body temperature at 990F with the help of a thick layer of fat below the skin. This layer of fat is called blubber. Whales have lungs and breathe air through the blowhole or nostrils on top of their heads. Calves are born alive, they are supplied milk by their mother and, yes, they have a belly button. A male is known as a bull, a female is called a cow, and a baby is a calf.
A group of whales is a pod.
There are a number of ways whales are grouped. The two major types of whales are baleen (BEY-lean) whales and toothed whales. Baleen is similar to what your fingernails are made of and are arranged in plates or fringes, which hang from the upper jaw along the sides of the mouth. The baleen whale opens its mouth wide and takes in huge gulps of food and water. It has pleats or folds on its throat, which expand to allow large amounts of water to enter the mouth. The water is squeezed out the side of the mouth trapping the food on the baleen plates. The whale uses its tongue to scrape the food from the plates and then it swallows the food. Whales that feed like this are known as gulpers.
The whale’s pleated throat classifies it as a rorqual (ROAR-qual). Blue, Fin, and Humpback Whales are rorquals. Whales such as the Great Right and Bowhead Whales are called skimmers. This type of whale, which does not possess the pleats along its throat, keeps its mouth open while moving. It scoops up as much food as possible. Then, as the other whales, it uses its tongue to scrape the food from the baleen and swallow it. Whales such as Grey and Sei Whales feed as both gulpers and skimmers. Because the food is filtered from the water all baleen whales are also known as filter feeders.
Baleen whales such as Humpbacks (see drawing) perform a feeding procedure called bubble feeding. A group of Humpbacks will herd fish such as herring in a small area. Then the whales will swim below the herring releasing thousands of bubbles. The herring are trapped in the bubbles and the whales, with open mouths, swim upwards taking in as much food as they are able.
Toothed whales include the ever-popular Killer Whale. Other toothed whales are the Sperm Whale (of Moby Dick fame), Pilot Whale, Porpoises, and Dolphins. These whales are predators and hunt their prey. Predators will take fish and squid. The only true flesh eater is the Killer Whale, which will feed on seals, sea lions, and penguins.
One famous myth about whales is that they blow water through their noses. Actually when a whale comes to the surface it exhales and what you see is the warm water vapor from its lungs cooling and condensing into liquid water. You do this yourself when you exhale in cold weather. This is known as the spout and the shape of the spout can help identify the type of whale. Baleen whales have a double blowhole while toothed whales have a single blowhole. The Blue Whale is the largest animal that has ever lived. It may weigh some 196 tons and it has to maintain this weight. Blue Whales feed on small crustaceans called krill and to keep their weight they have to eat about 4 tons of these little guys every day. Now that’s a lot of calories!
Sperm Whales have been known to dive and remain beneath the surface for 90+ minutes. Bottlenose dolphins have been known to stay underwater for two hours! Humpback Whales are well known as the "singers" of the cetaceans. They make various sounds such as low moans, short thumps, chirps and whistles, and clicking. Bowheads are also "singers." The Right Whale was so-named because it floated when killed making it the "right whale" to hunt.
Unfortunately because of over-hunting, many whales today, it is believed, may never make a comeback and they will eventually become extinct.
Questions? Ask Steve: Drawing firstname.lastname@example.org.