Cetology
Encyclopedia
Marine mammal
Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...
science that studies the approximately eighty species of whales, dolphins, and porpoise
Porpoise
Porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen...
in the scientific order Cetacea
Cetacea
The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...
. Cetologists, or those who practice cetology, seek to understand and explain cetacean evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
, distribution, morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
, behavior, community dynamics, and other topics.
History
Observations about Cetacea have been recorded since at least classical times. Ancient GreekAncient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...
fishermen created an artificial notch on the dorsal fin of dolphins entangled in nets so that they could tell them apart years later.
Approximately 2,300 years ago, Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
carefully took notes on cetaceans while traveling on boats with fishermen in the Aegean Sea
Aegean Sea
The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...
. In his book Historia animalium (History of animals), Aristotle was careful enough to distinguish between the baleen whales and toothed whales, a taxonomical separation still used today. He also described the Sperm Whale
Sperm Whale
The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...
and the common dolphin
Common dolphin
The common dolphin is the name given to two species of dolphin making up the genus Delphinus.Prior to the mid-1990s, most taxonomists only recognised one species in this genus, the common dolphin Delphinus delphis...
, stating that they can live for at least twenty-five or thirty years. His achievement was remarkable for its time, because even today it is very difficult to estimate the life-span of advanced marine animals. After Aristotle's death, much of the knowledge he had gained about cetaceans was lost, only to be re-discovered during the Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...
.
Many of the medieval texts on cetaceans comes mainly from Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
and Iceland, most come about around the mid-13th century. One of the better known is Speculum Regale
Konungs skuggsjá
Konungs skuggsjá is a Norwegian educational text from around 1250, an example of speculum literature that deals with politics and morality...
. In this text is described various species that lived around the island of Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...
. It mentions "orcs" that had dog-like teeth and would demonstrate the same kind of aggression towards other cetaceans as wild dogs would do to other terrestrial animal
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
s. The text even illustrated the hunting technique of Orcs, which are now called Orcas. The Speculum Regale describes other cetaceans, including the Sperm Whale and Narwhal
Narwhal
The narwhal, Monodon monoceros, is a medium-sized toothed whale that lives year-round in the Arctic. One of two living species of whale in the Monodontidae family, along with the beluga whale, the narwhal males are distinguished by a characteristic long, straight, helical tusk extending from their...
. Many times they were seen as terrible monsters, such as killers of men, and destroyers of ships. They even bore them odd names such as "Pig Whale", "Horse Whale", and "Red Whale". But not all creatures described were said to be fierce. Some were seen to be good, such as whales that drove shoals of herring towards the shore. This was seen as very helpful to fisherman.
Many of the early studies were based on dead specimens and myth. The little information that was gathered was usual length, and a rough outer body anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
. Because these animals live in water their entire lives, early scientists did not have the technology to go study these animals further. It was not until the 16th century that things would begin to change. That cetaceans would be proved to be mammals rather than fish.
Aristotle, as said above, argued they were mammals. But Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
stated that they were fish, and it was followed by many naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
s. However, Pierre Belon
Pierre Belon
Pierre Belon was a French naturalist. He is sometimes known as Pierre Belon du Mans, or, in Latin translations of his works, as Petrus Bellonius Cenomanus.Belon was born in 1517 at Soulletiere near Cérans-Foulletourte...
(1517–1575) and G. Rondelet (1507–1566) persisted on convincing they were mammals. They argued that the animals had lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s and a uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
, just like mammals. Not until 1758, when Swedish botanist Carolus Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...
(1707–1778) published the tenth edition
10th edition of Systema Naturae
The 10th edition of Systema Naturae was a book written by Carl Linnaeus and published in two volumes in 1758 and 1759, which marks the starting point of zoological nomenclature...
of Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
, were they seen as mammals.
Only decades later, French zoologist and paleontologist Baron Georges Cuvier (1769–1832) described the animals as mammals without any hind legs. Skeletons were assembled and displayed in the first natural history museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
s, and on a closer look and comparisons with other extinct animal fossils led zoologists to conclude that cetaceans came from a family of ancient land mammals.
Between the 9th-20th century, much of our information on cetaceans came from whaler
Whaler
A whaler is a specialized ship, designed for whaling, the catching and/or processing of whales. The former included the whale catcher, a steam or diesel-driven vessel with a harpoon gun mounted at its bows. The latter included such vessels as the sail or steam-driven whaleship of the 16th to early...
s. Whalers were the most knowledgeable about the animals, but their information was regarding migration routes and outer anatomy, and only little information of behavior. During the 1960s, people began studying the animals intensively, often in dedicated research institutes such as the Tethys Research Institute
Tethys Research Institute
The Tethys Research Institute is a non-governmental organization that specializes in carrying out research on cetaceans, which was founded in 1986....
in Milan. This came from both concern about wild populations and also the capture of larger animals such as the Orca, and gaining popularity of dolphin shows in marine park
Marine park
A marine park is a park consisting of an area of sea sometimes protected for recreational use, but more often set aside to preserve a specific habitat and ensure the ecosystem is sustained for the organisms that exist there...
s.
Studying cetaceans
Dung
Dung may refer to:* Dung, animal feces* Dung, Doubs, a commune in the Doubs department in the Franche-Comté region in eastern France* Mundungus Fletcher or "Dung", a character in the Harry Potter novels* Dung beetle...
that can tell important information about their diet. Many times Cetology consists of waiting and paying close attention.
Cetologists use equipment including hydrophone
Hydrophone
A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates electricity when subjected to a pressure change...
s to listen to calls of communicating animals, binoculars and other optical devices for scanning the horizon, cameras, notes, and a few other devices and tools.
An alternative method of studying cetaceans is through examination of dead carcasses that wash up on the shore. If properly collected and stored, these carcasses can provide important information that is difficult to obtain in field studies.
Identifying individuals
In recent decades, methods of identifying individual cetaceans have enabled accurate population counts and insights into the lifecycles and social structures of various species.One such successful system is photo-identification. This system was popularized by Michael Bigg
Michael Bigg
Michael Bigg was a Canadian marine biologist who is recognized as the founder of modern research on killer whales. With his colleagues, he developed new techniques for studying killer whales and conducted the first population census of the animals...
, a pioneer in modern orca (killer whale) research. During the mid 1970s, Bigg and Graeme Ellis photographed local orcas in the British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
n seas. After examining the photos, they realized they could recognize certain individual whales by looking at the shape and condition of the dorsal fin, and also the shape of the saddle patch. These are as unique as a human fingerprint; no one animal's looks exactly like another's. After they could recognize certain individuals, they found that the animals travel in stable groups called pods. Researchers use photo identification to identify specific individuals and pods.
The photographic system has also worked well in humpback whale
Humpback Whale
The humpback whale is a species of baleen whale. One of the larger rorqual species, adults range in length from and weigh approximately . The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the...
studies. Researchers use the color of the pectoral fins and color of the fluke to identify individuals. Scars from orca attacks found on the flukes of humpbacks are also used in identification.