Whale Primer, with Special Attention to the California Gray Whale
Part 2
Although a whale can be sighted by the telltale spout, a frightened whale may elude detection by exhaling just before surfacing, so that nothing more than a foamy patch is produced. Under these situations the whale does not expose the usual amount of buoyant head, but only the nostrils. A disturbed whale can dive, and then surface a mile or two away, or it may not move at all, preferring to hide on the bottom or among rocky reefs or in the kelp. The California gray whale was judged by whalers to be the most wary and elusive of them all.
_Swimming Adaptations_
The most essential features needed for the successful invasion of the marine habitat were those necessary for efficient propulsion. Fish, eons before, had solved the hydrodynamic equations necessary for movement through such a resistive medium. This solution required a streamlined form with a tail for propulsion, placed at the very end of the body. Extra fins were employed for maneuvering and for balancing. Whales, too, have reached the same solution, and man, when he finally develops sufficient highspeed submarines, will employ the same solution, namely streamlining. As a consequence, all whales look alike, differing principally in the degree of streamlining, color or size. In a whale's streamlined body there can be no sharp discontinuities to accommodate the head, the neck, the trunk, and lastly the tail. Instead these features must grade imperceptibly one into the other. The only allowable discontinuity is the end of the tail which is expanded into fanshaped lobes to function like a propeller.
These features, called tail flukes, are driven up and down in contrast to the tail of a fish which is driven sidewise. Whales have long banks of muscle along either side of the backbone which attach to the tail flukes by means of tendons. This makes it unnecessary to disturb the streamlined form by bending the hind part of the trunk as is necessary when fish drive with their tails. It also makes it possible to devote a great deal more muscle to the task. The power developed by these muscles is prodigious, capable of driving a 100-ton body through the water at speeds up to 20 knots. Wounded whales can smash a 20-foot whaleboat to bits with a single slap of the tail.
The hind limbs which were useful on land have been eliminated and all that persists are vestigial bones or cartilages which are buried deep below the surface of the body. The forelimbs have undergone reduction and modification into flippers which assist in the turning and diving. The flippers are useful in other ways, providing a platform on which the baby may stay when danger threatens. They are also useful during courtship and mating, but not for combat. The toothless whales do not have too much to fight with. They may strike an adversary with the powerful tail flukes, and during courtship the males jostle and bump each other.
Whales are almost completely hairless, save for a few bristles on their heads. Certainly the elimination of hair has improved streamlining, and has reduced the frictional drag. Furthermore, continuously wet hair could not have been of much value in keeping the whale warm. It is also possible that a hairy whale would have been very much bothered by skin parasites which would have flourished in the quiet water between the hairs. However, if this prompted the loss of hair, it was in vain for now the streamlined bodies of humpbacks and right whales are marred by large encrusting barnacles. It is surprising that the barnacles do not completely cover the whales. Perhaps they are scraped off on the bottom, or they cannot flourish during the long migration or in plankton-impoverished waters of the winter quarters. At any rate the parasites are kept partially under control so that much of the streamlined surface is unblemished.
If the physical properties of water forced upon whales a common shape, they did at least, by the buoyant effect, free the animals of the need for structural and muscular developments to support themselves against the pull of gravity. Free of this structural problem, whales were able to evolve into the largest mammals which the world has ever known. As they became larger, they had to shift in their feeding to slower and less maneuverable prey. It would appear that the porpoises, which feed on the rapid-swimming, elusive fishes, are small in order to catch their prey. The whales, which have specialized to feed on the jet propelled squids, were able to evolve into much larger whales because they could capture the squid either by stealthy approach or by sucking the squid into the mouth, thus counteracting its jet.
Whale Types
_Porpoises and Dolphins_
Whales are known technically as cetaceans (pronounced seh-TAY-shuns); so also are the various porpoises and dolphins which are mostly eaters of fish. These are certainly the most numerous of all the cetaceans, making up in numbers for their small size (6 to 8 feet). A few species range between 20 and 30 feet. Porpoises and dolphins congregate around schools of fish. Therefore fishermen are constantly on the lookout for a sight of them. Since not infrequently the porpoises break the surface of the water, leaping completely clear as if for a look around, they are not difficult to locate. Porpoises and dolphins can be seen most frequently in coastal waters where fish are most abundant. The porpoise and dolphin families contain a great many species and it is beyond the scope of this treatise to differentiate or name them all. However, these families include such unique forms as the killer whale, narwhal, white whale (or beluga as it is known to the Eskimos), and the pilot or black whale. Generally one associates cetaceans with the ocean, so it may come as a surprise to find that four dolphin species live in such major rivers as the Amazon, La Plata, Ganges, and the Yangtze.
In dolphins, the mouth protrudes beyond the head as a beak or snout, and in porpoises, the front of the head is blunt or gently rounded. It is impossible to avoid confusion if one uses common names to separate the various whales. Even though the word whale properly covers all the kinds, to some it connotes only the larger species. Such a distinction is wholly arbitrary, and cannot properly differentiate the natural groupings of whales to which zoologists have assigned technical names. It would be impossible to summarize the variety of common names which many of the species have acquired through the centuries. The only solution to this is to refer to the whales by the technical names which connote relationship. (For readers who desire this differentiation, a brief listing of the groups and representatives of each are provided in an appendix.)
BLUE WHALE (SULPHUR-BOTTOM WHALE) FIN-BACK WHALE (COMMON RORQUAL) GREENLAND RIGHT WHALE (BOWHEAD WHALE) BLACK RIGHT WHALE SEI WHALE HUMP-BACKED WHALE (unlabelled in picture) CALIFORNIA GRAY WHALE LITTLE PIKED WHALE (LESSER RORQUAL) PYGMY RIGHT WHALE The Sperm Whale is given here for size comparison only.
SPERM WHALE BOTTLE-NOSE WHALE KILLER WHALE PILOT WHALE (BLACKFISH) CUVIER'S BEAKED WHALE FALSE KILLER WHALE TRUE'S BEAKED WHALE NARWAL WHITE WHALE (BELUGA) PYGMY SPERM WHALE BOTTLE-NOSE DOLPHIN COMMON DOLPHIN COMMON PORPOISE
_Squid Eaters_
The bottlenose whales are nearly toothless, feeding on squid like their close relatives, the sperm whales. Porpoises and dolphins possess many sharp conical teeth on both the upper and lower jaws, although the narwhal which is related to them, breaks the rule by being toothless save for the tusklike canine of the male. In this instance either the right or left tooth elongates to produce an 8-foot spear. The other tooth does not break the gum, and this is the condition found in the female where both are rudimentary and not evident. The bottlenose whales have but a single pair of teeth in the lower jaw, and their relatives, the sperm whales, have 18-28 conical teeth per side on the lower jaw, and these when fully grown may be 8 inches in length. Pockets are provided in the toothless gum of the upper jaw to accommodate the teeth when the mouth is closed.
The decline in the number of teeth in the sperm and bottlenose whales is thought to be the elimination of structures which are no longer useful. Whereas a porpoise's long mouth, bristling with sharp teeth, insures the hooking and retention of a slippery active fish, a small mouth with a few teeth is adequate to crush and slurp down the squid and the weak-swimming fishes of the abyssal depths.
The sperm whale is the largest of the squid feeders, reaching 60 feet. There is a diminutive counterpart, the pygmy sperm whale, which reaches 13 feet. It is exceedingly rare, whereas the sperm whale is abundant in temperate and tropical seas. The beaked whales complete the groups specialized for feeding on squid. Besides the modification of the mouth, all these whales are noted for their ability to dive to great depths where their food abounds. Not only can they dive to great depths, but they can stay submerged for long periods--up to an hour? Sperm whales have been found entangled in the submarine cables which were known to be on the bottom at a depth of 3,000 feet. It is clear that such feeding habits have opened up vast areas of the oceans to these species.
_Filter Whales_
The whalebone whales seem to have undertaken two different lines of specialization in feeding: The right whales developed an enormous head with a very large filter plate, whereas the rorquals are much more streamlined with a small filter plate. The ability of the latter to gather food is insured by the pleated throat. The right whales lack a dorsal fin and are decidedly less streamlined. The rorquals have a dorsal fin. There are two species which do not exactly fit in either group. The humpback whale appears to be like the rorquals in that it has a pleated throat and a suggestion of a fin. It is however, a very bulky slow swimming species. The California gray whale, apparently, is intermediate between the two groups and may be thought to be a survivor of the ancestral stock from which both groups differentiated. It has neither a pleated throat nor a fin. The gray whale, like the right whale, has been slow to recover from whaling. It is likely that the populations were never very large. Only the rorquals seem to have the numbers needed for large whaling operations.
Significance of Blubber
_Heat Conservation_
As whales extended their operations into the icy waters of polar regions or into the cold waters of the ocean depths, they had to develop means of keeping warm. Anyone who has attempted to swim in cold water knows how quickly one loses his body heat and becomes chilled. Whales minimize the heat loss by accumulating a thick layer of fat just below the surface of the skin. The fatty layer, called blubber, not only keeps the whale warm, but it also provides for food storage. It has already been stressed how important it is for whales to survive long periods without eating, so it is likely that the two specializations arose together.
There are, however, extensive areas of the whale which cannot be blanketed with fat and these are the flippers and the large tail flukes. It has been observed that the blood going into these structures gives up its heat not to the outside but to the veins which parallel and surround the arteries. By this anatomical feature most of the heat which would otherwise be lost to the water, is recaptured by the veins which deliver the heat back into the body. Of course, this means that the tissues of the tail flukes and flippers function at temperatures much lower than those found within the body. Here we find that nature was using the principal of the heat exchanger long before man discovered it or put it to work in air conditioning.
Whales are so well insulated that they stay quite warm 24-36 hours after death. Whalers must process the whales quickly, for otherwise, at the elevated body temperature, decomposition proceeds most rapidly and ruins much of the meat. It is possible that the baleen-bearing whales do not cross the warm equatorial waters because they overheat. No one has yet determined whether the newborn young have a sufficient layer of fat to protect them from the cold water, and it has been suggested that whales calve in temperate waters to prevent the babies from being chilled. However, there are species like the narwhal and the white whale which calve in Arctic waters.
_Buoyancy_
Another aspect to the extensive deposits of fat is that these tissues are lighter than water and help counteract the heaviness of the whale's body so that with the assistance of the lungs neutral buoyancy is achieved. The fat is accumulated in between the muscle strands, and in fact, in every available nook and cranny.
_Food Storage_
Much of this fat is drawn upon for food. Whenever a whale is existing on its fatty tissue, acetone is one of the waste products which must be eliminated in the breath. This pungent material makes the breath very strong and noticeable at these times. Certainly among whales, there is no stigma attached to being fat or having halitosis.
Ordinarily fatty tissues only accumulate when there is a surplus of food over the needs of the animal. You might suspect that whales would need to stockpile fat first, in order to remain warm and buoyant, and that growth would be curtailed and accomplished last. However, studies on the growth of whales show that the efficiency of food gathering is so high and food so plentiful, that growth not only continues but at a tremendous pace.
Sexual Maturity
Whales mature sexually between their third and seventh years. Toothed cetaceans attain sexual maturity later than filter-feeding whales. A blue whale is sexually mature at 5 years, whereas porpoises require at least 7 years. Most filtering whales are sexually mature in 2 or 3 years. Whales are not fully grown at sexual maturity, but they continue to grow for years. In most mammals growth stops with sexual maturity. Female whales generally can be expected to produce a baby every other year, for the gestation period is approximately one year. Babies are nursed for about 9 months. At birth the baby is completely formed and active, but lacking baleen, must nurse. A blue whale baby at birth weighs approximately 8 tons, about 1/12th of the weight of the mother. The mother provides the baby with 50 gallons of milk a day. Since the nursing is done under water, and the baby must surface frequently to breathe, the act of nursing is very brief. Muscles in the breasts of the mother force the milk into the baby's mouth in large amounts. The baby will double its length in 7 months, which averages to a daily weight gain of 220 pounds. During all this time the mother must fatten for the winter ahead, and perhaps continue to grow herself.
Life Span
It is not known for certain how long a whale may live after completing its growth. At the present time, commercially important species seldom attain physical maturity before being captured. Many whales which are captured are measured for scientific study. Such measurements also keep the whalers from taking undersized juveniles. Whales apparently do not live to be very old. Fifty years appears to be the best current estimate of a life span.
Whale Intelligence
Whales are apparently very intelligent animals. Whalers have remarked how difficult it is to approach whales which have previously escaped. The gray whales were observed actually avoiding the coast after shore whaling had been carried out for a few seasons. Animal trainers have found the toothed whales particularly apt pupils, and these animals are the stellar attraction of the various oceanaria.
Whale Senses
_Sight_
Little is known, however, about the capabilities of the various sensory organs. Certainly the eyes are very important and are effective under water. It is not likely that the eye is very effective out of water, even though whales do elevate the head out of the water for a look around. The behavior has been appropriately called "spyhopping," and it is manifested usually in the ice floes. Killer whales are believed to search the sea's surface and the edge of the icebergs for seals and birds.
_Hearing_
Whales appear to have very acute hearing. The report of a whaling gun will alarm whales which have previously tolerated the whaling vessel close aboard. Whalers have noted that in very foggy weather whales are much more difficult to approach because of the increased sensitivity to noise. The toothed cetaceans which are gregarious are capable of a great variety of vocalizations. Much of this is ultrasonic to man and it has been suggested that these emissions are used like man's sonar for finding obstacles and food. Considering the limited range of vision possible in water which is usually hazy or turbid, such a feature would be most useful. There is a continual chatter among members of a porpoise school, or gam, as the whalers call them. The accumulated noise serves as a beacon to which straying members can home when they have gotten out of visual range, which incidentally is under 300 feet. No one yet knows exactly how these animals can produce these sounds without being able to move air across the vocal chords. They do not exhale under water, and yet they are continually noisy.
_Smell_
The sense of smell is not important to whales, and the organ was abandoned when the nostrils were shifted to the back of the head and modified for diving. Although man may never be able to test whales experimentally for their sensual acuities, it is quite apparent that they are fully aware of their environment. They clearly recognize the environmental signposts which guide them to and from their various areas. Oceanographers are not nearly as adept in knowing where they are on the ocean. Whales clearly recognize their own particular kind, and they do not intermingle. Incidentally, man finds it difficult to differentiate some of the whale species. Because of the rarity of specimens and information, the identity of some species may still be in doubt.
Habits
Filtering whales, unlike the gregarious porpoises and dolphins, seldom school. Even when they appear to be abundant in a limited area, they have congregated for feeding and not for social interaction. Toothed cetaceans, on the other hand, are generally sociable. The sperm whale travels in large groups of females dominated by a single bull whale. The other males have been driven away and the victorious male exercises control of the harem only as long as he wins these contests. Once the dominant male is defeated, he becomes a solitary individual.
Enemies
_Killer Whales_
Whales, by virtue of their size and speed, are not preyed upon by other animals. The killer whale, however, has the size and inclination. Generally, it is content to capture seals, sea birds, and fishes, and it does not range too far from this prey. There have been isolated reports of killer whales attacking the gray whale. The gray whale is described as being very disturbed whenever a killer whale appears. On the coast of Siberia the gray whale will hide in very shallow water and if cornered is said to go into shock, floating at the surface, stomach up, while the killer whale bites at the tongue and flippers. Perhaps reports like this have been improperly interpreted. It is easy to understand how killer whales would congregate around the catch of the whaler. Recently studies on the loss of hooked tunas from the long-line fishery of the Japanese, show that killer whales are adept at stealing fish along the setline. Additional studies on the natural history of the killer whale must be made before its relationship to other whales can be properly assessed.
_Parasites_
If whales generally lead a charmed life with respect to predators, they still have their share of parasites both external and internal. Their huge bodies are ideal platforms for the growth of barnacles which have specialized for this unusual habitat. Another very annoying skin parasite is the whale louse, which is a flattish small crustacean which clings by claws to the delicate skin. The digestive tract of the whale provides a wonderful habitat for round worms and tapeworms. Like their host, these parasites are the largest of their kind. Other organs such as the kidneys, liver and lungs are infested too.
Sperm whales suffer from another affliction which is an obstruction of the intestine by a fatty concretion which forms from the bile. Ordinarily these are passed from the digestive tract when small, but if they are retained and continue to grow, an obstruction is possible. The material is a grayish wax which is known as ambergris. It is used by the perfume industry to make permanent blends of various fragrances. Most of this material is obtained by whalers when they process the sperm whale. Only rarely does the material float ashore after the death of the unfortunate producer. Nowadays the value of ambergris is but moderate.
Whale Abnormalities
Whales are found with healed broken bones which must have been incurred by fighting and other collisions. The skin of whales is mottled with scars which were produced by parasites and by fighting. Toothed whales are especially scarred from the raking by the teeth of an adversary during battles for dominance. For at least 5 centuries, man has preyed on the whale. In recent times navies of several nations have been alarmed by unidentified underwater objects which cannot easily be distinguished from submarines. Some of these contacts are produced by whales. The counter measures not only cost the whale its life, but also causes the navies unnecessary expenditures of depth charges and time, and produce considerable tension and anxiety.
Inadequate Knowledge of Whales
Whales have been extensively described both in popular and scientific writings. However, their story is by no means complete or correct. It will be many years before all the information can be obtained on these animals which range the wide oceans where man must study them under great disadvantage. Until man has the underwater mobility and maneuverability of whales, he will have to be content with surmise and interpretations based on limited observations.
There is a great deal known about the anatomy and fine structure of whales. You can certainly admire the work of the early anatomists who persevered in dissecting the partially decomposed carcasses of stranded specimens. What a contrast to the opportunity afforded now to the anatomist who need merely be present on a whaling ship station to receive any part which he wishes to examine. It takes the whaling station 4 to 6 hours to butcher a whale completely.