The cetaceans are the marine animals most famous for their presence in ancient stories and legends. They are animals that have always aroused great interest on the part of human beings. These animals, in general, are great unknowns that, little by little, are disappearing without us apparently doing anything.
In this article on our site we will talk about cetaceans, what they are, their characteristics, where they live and other curiosities. Do you want to know more about these inhabitants of the deep sea? Keep reading!
What are cetaceans?
The order of the cetaceans is made up of two suborders, the mysticetes, formed by the baleen whales, and theodontocetes , made up of cetaceans with teeth, such as sperm whales, dolphins and killer whales.
The evolution of cetaceans has led to a similarity between these two living suborders, resulting from the evolutionary convergence The common structural characteristics between the two groups, such as the shape of the body, the position of the nostril or spiracle on the head, the absence of vocal cords, and the similar shape of the lungs suggest that these species have evolved from different ancestors to animals that are very similar to each other.
Therefore, cetacean mammals are lung-bearing animals that inhabit our seas and oceans, although certain species live in rivers.
Characteristics of cetaceans
Cetacea are characterized by their anatomy, morphology, physiology and habitat. The main characteristics of cetaceans are:
- Exhibit an Unusually wide range of body mass which influences oxygen storage and utilization capabilities. This prevents the onset of hypoxia or lack of oxygen in your tissues.
- During diving, your heart shunts blood to your brain, lungs and muscles to allow swimming and continued body function.
- The trachea is shorter than in land mammals and does not communicate with the esophagus. It is linked to the spiracle, through which they take in and expel air.
- They have large reservoirs of fat to prevent hypothermia when they dive to greater depths.
- The hydrodynamic shape of its body allows for faster swimming speeds and prevents the ravages of large pressure changes.
- They don't have vocal cords. Instead they have an organ called a melon that they use to communicate or hunt by echolocation.
- They have a very thick skin whose outermost layer, the epidermis, is continuously renewed at high speed.
- At birth, the pups have hair, but this disappears after a few months of life.
- The number of fins depends on the species. Although they all have pectoral and caudal fins.
- Some species have teeth, all the same size and shape. Others have barbs, which you use to filter water.
Where do cetaceans live?
The habitat of cetaceans is the aquatic environmentWithout it, their skin would dry out and they would die. Some cetaceans live in circumpolar waters, for example the beluga (Delphinapterus leucas) or the narwhal (Monodon monoceros), so they are adapted to low temperatures. Others have a more tropical distribution, such as the pilot whale (Globicephala melas) and the pilot whale (Globicephala macrorhynchus).
Some of these animals live in freshwater, they are highly endangered species of cetaceans, mainly due to the pollution of rivers, the construction of dams and discriminated hunting. The list of cetaceans that live in rivers is:
- Bolivian dolphin (Inia boliviensis)
- Araguaia river dolphin (Inia araguaiaensis)
- Pink Dolphin (Inia geoffrensis)
- Silver Dolphin (Pontoporia blainvillei)
- Baiji (Lipotes vexillifer)
- Indus Dolphin (Platanista minor)
- Ganges Dolphin (Platanista gangetica)
The vast majority of cetaceans make annual migrations from their feeding grounds to their breeding grounds. This is the time when these animals are most unprotected.
In the image we can see a pink dolphin:
Types of cetaceans:
Cetaceans are classified into two large groups: mysticetes and odontecetes.
1. Mysticetes
Mysticetes, commonly called whales, are less numerous and are mainly characterized by having baleen instead of teeth. They are animals of enormous size and usually live in cold waters. Some of its species have not been seen during whale watching for decades. The most common species of baleen whales are:
- Pacific Right Whale (Eubalaena japonica)
- Greenland Whale (Balaena mysticetus)
- Fin whale (Balaenoptera physalus)
- Blue Whale (Balaenoptera musculus)
- Humpback Whale (Megaptera novaeangliae)
- Grey whale (Eschrichtius robustus)
- Pygmy right whale (Caperea marginata)
In the image we can see a fin whale:
two. Odontocetes
Odontocetes are cetaceans with true teeth, in greater or lesser numbers. They are very numerous and include a good variety of species. They are all carnivorous animals. The best known species of odontocetes are:
- Pilot pilot whale (Globicephala melas)
- Southern dolphin (Lagenorhynchus australis)
- Orca (Orcinus orca)
- Striped dolphin (Stenella coeruleoalba)
- Bottlenose dolphin (Tursiops truncatus)
- Atlantic dolphin (Lagenorhynchus acutus)
- Sooty dolphin (Lagenorhynchus obscurus)
- Harbor porpoise (Phocoena phocoena)
- Vaquita porpoise (Phocoena sinus)
- Spectacled Porpoise (Phocoena dioptrica)
- Sperm whale (Physeter macrocephalus)
- Pygmy sperm whale (Kogia breviceps)
- Dwarf sperm whale (Kogia sima)
- Blainville beaked whale (Mesoplodon densirostris)
- Gervais's beaked whale (Mesoplodon europaeus)
- Gray's beaked whale(Mesoplodon grayi)
In the image we can see a pilot whale:
