Whale is any of the largest species of marine mammals that belong to the family of Cetacea. It is possible to use the word whale is used in the context of any cetacean, including dolphins and porpoises, however, generally it is used to refer to animals that are more than three meters (10 feet) long. A notable instance of this can be the 2.7-metre dwarf Sperm whale ( Konia sinus) named for its striking resemblance to the larger sperm whale named Konia sinus. Whales are among the largest known animal species, whether living or fossilized, with an absolute maximum of the blue whale (Balaenopterid Musculus) that could be more thirty meters, and up to 200 tonnes (220 shorter [U.S.] tons).
Whales can be found throughout the oceans and seas of the world all the way from to the Equator up to the Polar ice, with the exception those living on land in the Caspian as well as Aral seas. They are mammals, and share the most distinctive characteristics of this group that they breathe air, have warm blood, birth live, feed their babies with milk, and are hairy.
They are all aquatic with special adaptations like tail flukes and flippers for living in the water. Whales have to surface frequently to breathe, and they have to empty their lungs in greater detail than other mammals. They also breathe the form of a breath that is almost explosive and called blows. The blows are evident because the water vapor from whales’ hot breath condenses after it is released.
Despite being in a place with much better thermal conduction properties as air, marine mammals, like all mammals, have to control their temperature. Hair, however, is confined to the headand appears as whiskers that are isolated (vibrissae) close to the mouth and blowholes. Blubber is an insulating layer that protects smaller whales against hypothermia. Large whales face the exact opposite issue in that they could generate too much heat. they have sophisticated thermoregulation mechanisms to stop them from overheating.
Due to the limited utility of underwater vision Whales rely on the sound system to interpret and perceive their surroundings and communicate, often over huge distances. Biologists have calculated that sound waves of fin whales at 10 Hz ( Balaenopterid physiques) for instance, can travel up to 1 800 km (1,100 miles). Whales with teeth can make sounds and interpret reflections using active echolocation. The extent to which baleen whales possess this ability is not known.
After internal fertilization female whales become pregnant for approximately one year. The newborns are quite large at birth, ranging from one-third to half the length of their mother. They are fed for approximately six months with extremely rich milk that is almost 50% fat. Whales have a pair of Nipples that are located in the rear of the abdomen, near the opening of the genital area.
The first fossil whales have been discovered from rocks that are approximately fifty million years older (Early Eocene Epoch). The extinct members of the suborder Archaeoceti are the earliest whales from which modern whales derive. They have many resemblances to terrestrial mammals, such as the distinct dentition (heterodonty) comprised of canines, incisors, premolars, and molars. Archeocytes spawned the living suborders, namely Baleen whales (suborder Masticate) and the toothed whales (suborder Odontocete).
Masticates are a species of fish with baleen plates. They consume small prey via the mouthful, mostly as floating (planktonic) crustaceans like copepods and krill. However, they can also eat small schooling fish, or squid. A notable deviation from this can be seen in the gray whale ( Eschrichtius robustus) that mainly eats shrimp as well as other creatures that live in the bottom It scoops up mud, then strains it through the baleen plates, while retaining its food. Odontocetes have teeth that are simple (homodonty) and hunt individuals of squid, fish as well as other prey. The biggest odontocete is the Sperm whale ( Physeter catodon) is occasionally fed on huge squid.
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