What are whales?
The whales are a group of marine cetacean mammals, of which four different species are known to date. However, the term “whale” is commonly used for any large cetacean like sperm whales. Humanity has known these animals since ancient times and was often inspired by them to create mythological sea monsters. These are large marine life animals, whose species include the largest living animals on the planet (the blue whale, Balaenoptera musculus). Like all mammals, whales are warm-blooded, air-breathing animals.
Capable of spending long periods submerged and then coming to the surface to replenish their air reserves and expel the water from their lungs using a jet that rises through the air, and that is one of the typical features of their presence. Whales are often considered a kind of immense “sea cows”, that is, tame animals that roam the deep seas, and that do not represent any danger to humanity, nor to other species beyond the small organisms on which they feed.
Characteristics of the whales
Broadly speaking, whales are characterized by the following:
- They are very bulky animals, one of the largest that exist on the planet, whose bodies can exceed, depending on the species, a wingspan of 35 meters and hundreds of tons. There are also smaller species, which can be around 3 meters long and weigh much less.
- They are marine mammals, that is, warm-blooded, air-breathing animals, for which they have two holes (spiracles) at the top of their head, through which they can expel the accumulated water and carry out the gas exchange. For this last reason, they have a tail arranged vertically, which allows them to quickly rise and fall.
- There are two types of whales: baleen like the blue whale and the teeth like the sperm whale. The former feed by filtering the water, and the latter instead devour their prey.
- They have solid bodies covered with a layer of fat that isolates their entrails from the cold waters of the deep sea and are capable of holding their breath for 45 minutes and reaching depths of almost a kilometer.
Strictly speaking, the four known species of whale are:
- Greenland whale (Balaena mysticetus)
- The southern right whale (Eubalaena australis)
- The glacial right whale (Eubalaena glacialis)
- The Pacific right whale (Eubalaena japonica)
Where do the whales live?
Different species of whales choose different habitats, almost always in the deep waters of the different oceans. For example, blue whales prefer the North Atlantic, while gray whales prefer the east and west of the northern Pacific Ocean.
Many species are migrants so they spend long periods in one place but go to specific sites to reproduce, as occurs with the southern right whale that visits the Atlantic coast of Argentina during several months of the year.
What do whales eat?
In general, the whales are carnivorous, although their respective diets usually consist of small fish, tiny crustaceans (such as krill), and zooplankton, which they filter from the water thanks to the set of baleen they possess and which measure from 5 to 25 cm in length. Instead, toothed species may feed on squid and other cephalopods in deep water.
How do whales reproduce?
Like all mammals, whales reproduce sexually and viviparously, with long gestations of almost a year at the end of which a single calf is born. The latter, at birth, measure about 5 meters and weigh around three thousand kilos, in the most voluminous species, and feed on breast milk during their first years of life.
How long do whales live?
The average lifespan of a whale is around 30 to 40 years., although it is known that some particularly bulky species can reach 200 years of age, thanks to their particularly slow metabolisms, such as the Greenland whale.