Are dolphins really as playful as sharks?
Whales and dolphins
Whales were worshiped long ago in many cultures. There is still a myth surrounding them today. The baleen whales impress with their gigantic bodies, the smaller toothed whales with their agile elegance and curiosity. Whales are difficult to spot - perhaps that is one of the reasons for the numerous myths and legends.
Feared and adored: the myth of the whale
The collective scientific term for whales and dolphins - "Cetacea" - has its origin in Greek mythology. Large whales, in particular, used to be thought of as sea monsters - in Greek also: keto or ketos.
The Bible also mentions a sea monster that swallowed the prophet Jonah and is said to have spat it out again after three days and nights.
In Luther's translation, this monster appears as a "whale". A mistake, because whales are actually mammals. Not all cetaceans had something sinister or monstrous about them.
Legends from ancient times
Even in ancient times there were reports of the astonishing helpfulness of dolphins. The ancient Greeks therefore revered them as protectors of travelers.
Whales and dolphins were also considered sacred in other cultures. The Maori saw the ancestors of all species in the whales. Legend has it that the first member of the tribe rode to New Zealand on the back of a whale more than 1000 years ago.
Some Northwest American Indian tribes also idolized whales, especially the killer whales. The Kwakiutl saw powerful supernatural beings in orcas. Other tribes believed that deceased chiefs would be reborn as killer whales.
Immortalized in literature: Moby Dick
In his novel "Moby Dick", Herman Melville immortalized the myth of the whale in literary form in the middle of the 19th century. In the book, the whaling captain Ahab and his crew mercilessly pursue an enigmatic white whale that once tore off his leg.
The remarkable novel about the archaic struggle between whales and humans marks the beginning of literary modernity and is one of the classics of world literature today. It has been filmed several times by Hollywood and translated into German many times.
Gentle giants: baleen whales
Baleen whales form one of two suborders of the Cetacea. All baleen whales are gigantic: even the smallest are more than six meters long.
The blue whale is the largest and heaviest. With a length of more than 30 meters, it can be as long as a medium-sized commercial aircraft, but is two to three times as heavy. This makes the blue whale the largest animal that has ever lived on earth.
Baleen whales are named for their whales, which sit on their upper jaws instead of teeth. Barten are several hundred fibrous horn plates that can be several meters long.
With these mouthparts, whales simply filter their food out of the water. To do this, they take in up to 80 tons of seawater at once in their huge mouths and press it out again through the whiskers, on which small marine animals get stuck.
Long journey: hikes
Almost all of the larger whales make long migrations. Many baleen whales specialize in krill. Tremendous numbers of these tiny crustaceans appear in the polar and sub-polar seas each summer.
In order to harvest the crab swarms in time for the krill season, baleen whales overcome huge distances - gray whales, for example, up to 10,000 kilometers per year.
The whales cannot stay in the northern latitudes because the water there is too cold for the calves. They therefore overwinter off the Mexican coast, where they also give birth to their offspring.
Playful and social: toothed whales
Toothed whales represent the second subgroup of the cetacea. They all have teeth instead of whiskers in their mouths and use them to kill their prey - mostly fish, octopus or sometimes other marine mammals.
Most toothed whales are significantly smaller than the gigantic baleen whales. Only the sperm whale reaches comparable dimensions with a length of up to 18 meters.
Toothed whales have developed a special form of perception called echolocation. Similar to bats, they can orientate themselves through the emission and echoes of ultrasonic sounds.
Toothed whales also have a large repertoire of communication noises. Most toothed whales are very communicative and live in fixed groups.
Big family: the dolphins
Toothed whales are a very species-rich group. Of the total of more than 80 whale species, a good 70 belong to the toothed whale.
A particularly large family among the toothed whales are the dolphins - they make up almost half of all whale species. Perhaps that is why dolphins are sometimes named and treated separately from the other whales.
In addition to the long-snouted dolphin species - such as the bottlenose dolphin known from dolphinariums, film and television - the family of dolphins also includes other species whose affiliation is not always so obvious. The killer whales (orcas) also belong to the group of dolphins, as do the pilot whales.
Long way back into the sea
The whales are descended from land mammals and are now most closely related to the hippos. How they returned to the water has long been a mystery.
Only spectacular fossil discoveries in recent years give a rough idea of this development, which is still hotly debated by researchers in detail. The transition from land to sea therefore took roughly ten million years.
Originally, the whales descend from the common ancestor of all artifacts, which today include pigs, camels, goats and sheep in addition to whales and hippos.
The pakicetus, a four-legged predator the size of a fox to a wolf, is considered to be the first ancestor of the whales. 50 million years ago it lived on the Southeast Asian coast - probably mostly on land, because outwardly it looked more like a rat than a whale today.
The 46 million year old find of a Rhodhocetus is considered to be the link between the land and water ancestors of the whales. The animal could no longer move well on firm ground because its legs had already been transformed into fins.
About 42 million years ago the Basilusauridae appeared and practically completed the development from land to aquatic mammals. They were now perfectly adapted to aquatic life.
With their stunted limbs and the nostril that had already moved halfway up, they already looked very much like today's whales. A caudal fin had also formed at the end of their streamlined body.
About 35 million years ago the Basilusauridae split into two different groups, from which the baleen and toothed whales emerged.
With hydrophone and GPS: whale research
Although humans have long had an interest in whales, very little is known about these animals. Because whales are difficult to watch.
They spend most of their lives far below the surface of the water, where they can hardly be seen with the naked eye and camera. That is why they are mostly bugged. With underwater microphones, so-called hydrophones, the sounds of the animals can be recorded underwater.
For long-term observation, scientists attach small measuring devices to the animals that determine their position via GPS (Global Positioning System) and record all movements.
Some of these devices even have a transmitter that can transmit the data to a satellite after surfacing. This eliminates the - often unsuccessful - search for the detached measuring devices.
By shooting at emerging whales with a special arrow that picks up small pieces of skin, researchers can obtain tissue samples from a distance. Genetic studies provide information about the relationships. Traces in whale fat residues in the sample reveal what the animals fed on.
Recognizing and counting: inventory research
It is not easy to determine which and how many whales are in a certain area. Many researchers recognize individual whales by their tail fin, the fluke. The unique features, such as scratches, patterns and the shape of the fluke, are recorded in image databases.
By comparing photos with the database entries, the scientists can then check whether the animals are new or already registered. Since whales can be distributed over large areas, it is often not known how many specimens of a species are still alive.
The population sizes of all whale species can only be roughly estimated - a challenge for zoologists and mathematicians. Boats and airplanes are used to search the areas of the sea where whales are suspected. An attempt is made to calculate the potential total stock from the sample counts.
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