Characteristics of the whales
Whales are a type of cetacean grouped in the Mysticeti suborder, characterized by having beards instead of teeth, as they have dolphins, killer whales, sperm whales or porpoises ( suborder Odontoceti ).They are marine mammals, fully adapted to aquatic life.Their ancestor came from the mainland, an animal similar to the current hippopotamus.
The physical characteristics of these animals are what makes them so suitable for underwater life.Its pectoral and dorsal fins allow them to maintain balance in the water and move through it.On the upper part of the body they have two holes or spiracles through which they take the necessary air to stay underwater.long periods of time.The cetaceans of the suborder Odontoceti have only one spiral.
On the other hand, the thickness of their skin and the accumulation of fat under it helps them keep constant your body temperature when they descend in the water column.The cylindrical shape of its body, which provides hydrodynamic characteristics, and the microbiota that lives in its digestive tract due to a mutualistic relationship, causes the whales to explode when they die stranded on the beaches.
What characterizes this group are the beards that they have instead of teeth and they are used for eating.When a whale takes a breath of water loaded with prey, it closes its mouth and with its tongue pushes the water out, forcing it to pass between the beards and leaving the trapped food.Then, with the tongue, collect all the food and swallow it.
Most have a dark gray coloration on the back and white on the belly, so as to pass better unnoticed in the column of water. There are no types of white whales, only the beluga ( Delphinapterus leucas ), which is not a whale, but a dolphin.Likewise, the whales are classified into four families, with a total of 15 species, which we will see in the following sections.
Types of whales of the family Balaenidae
The family of the balenids is formed by two different living genera, the genus Balaena and the genus Eubalaena , and by three or four species, according to if we rely on morphological or molecular studies.
This family includes the longest-lived species of mammal.They are characterized by having the jaw or lower jaw very convex, outward, what gives them that characteristic aspect.They do not have folds under the mouth that they can expand when they feed, so the shape of their jaw is what allows them to take large amounts of water with food.This group of animals also has a dorsal fin.They are a relatively small type of whale, measure between 15 and 17 meters, and are slow swimmers.
The Greenland whale ( Balaena mysticetus ), the only species of its genus , is one of the most threatened species by whaling, is in danger of extinction according to the IUCN but only the subpopulation ions surrounding Greenland [1], in the rest of the world there is no concern for them, so that Norway and Japan continue with the hunt.As a curious fact, it is thought to be the longest mammal on the planet, being able to live more than 200 years.
In the southern hemisphere of the planet we find the southern right whale ( Eubalaena australis ), one of the types of whales in Chile, important fact because it was here where, in In 2008, a decree declared them a natural monument, declaring the region «Cetaceous Hunting Free Zone».It seems that in this region the abundance of this species has improved thanks to the prohibition of hunting, but the death by entanglement with nets of continuous fishing.In addition, it has been proven that for some years, the Dominican seagulls ( Larus dominicanus ) have considerably increased their population and, unable to obtain food resources, devour the skin of the back of the young whales or whales, dying many because of the wounds.
North of the Atlantic Ocean and in the Arctic inhabits the glacial free whale or whale of the Basques ( Eubalaena glacialis ), who receive this name because the Basques were once the main hunters of this animal, leading them almost to extinction.
The latter species of this family is the North Pacific right whale ( Eubalaena japonica ), almost extinguished by hunting Whales of the Soviet State.
Image: free whale austral
Types of whales of the family Balaenopteridae
The balenopterids or rorcuales are a family of whales created by an English zoologist from the British Museum of Natural History in 1864.The name rorcual derives from the Norwegian and means "with grooves in the throat ".This is the distinctive feature of this type of whale.In the lower jaw they have folds that, when drinking water for food, expand allowing more to be taken at once; It would work similarly to the crop that some birds like the pelicans possess.The number and length of the folds vary from one species to another.To this group belong the largest animals that are known .Their length varies between 10 and 30 meters.
Within this family we find two genera: the genus Balaenoptera , with 7 or 8 species and the genus Megaptera , with a single species, the yubarta or humpback whale ( Megaptera novaeangliae ).This whale is a cosmopolitan animal, present in almost all seas and oceans.Its breeding area is tropical waters, as far as they migrate from cold waters Together with the glacial free whale ( Eubalaena glacialis ), it is the one that gets entangled in fishing nets more frequently.It should be noted that only humpback whale hunting is allowed in Greenland, where You can hunt up to 10 a year, and on the island of Bequia, 4 per year.
The fact that there are 7 or 8 species in this family is due to that remains to be clarified if the species of tropical whale should be divided into two Balaenoptera edeni and Balaenoptera brydei. This whale is characterized by having three cranial ridges.They can measure up to 12 meters long and weigh 12,000 kilograms.
One of the types of whales in the Mediterranean is the common rorcual ( Balaenoptera physalus ).It is the second largest whale in the world, after of the blue whale or blue whale ( Balaenoptera musculus ), reaching 24 meters in length.This whale is easy to distinguish in the Mediterranean from other types of cetaceans such as sperm whales ( Physeter macrocephalus ), because when diving it does not show the caudal fin, as if it were the latter.
The other species of whales in this family are:
- Rorcual norteno ( Balaenoptera borealis )
- Rorcual aliblanco ( Balaenoptera acutorostrata )
- Rorcual austral ( Balaenopt it was bonaerensis )
- Omura whale ( Balaenoptera omurai )
Image: humpback whale
Types of whales of the family Cetotheriidae
Until a few years ago it was believed that ketoteriids became extinct in the early Pleistocene, although recent studies by The Royal Society have determined that there is a living species of this family, the whale Frank Pygmy ( Caperea marginata ).
These whales live in the southern hemisphere, in areas of temperate water.There are few sightings of this species, most of the data come from ancient catches by the Soviet Union or stranding.They are very small whales, about 6.5 meters long, have no folds in the throat, so their appearance is similar to the whales of the family Balaenidae
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