
All living beings on the planet have their origin in the aquatic environment .Throughout evolutionary history, mammals have been changing and adapting to conditions on the surface of the earth until, several million years ago, some submerged themselves in the oceans and rivers, adapting to life under these conditions.
In this article of Animals and Pets Online we will talk about aquatic mammals, better known as marine mammals, since it is in the seas where a greater number of species of this type They inhabit.Discover the characteristics of these animals and some examples.
Characteristics of aquatic mammals
The life of mammals in water is very different from that of terrestrial mammals.In order to survive in this environment, they have had to acquire special characteristics during their evolution.
Water is a much denser environment than air and, in addition, offers greater resistance, so aquatic mammals have an extremely aerodynamic body that allows them to cope easily.Develop fins similar to those of fish has been a significant morphological change.It allows them to increase speed, direct swimming and communicate.
Water is a medium that absorbs much more heat than air, for This, the aquatic mammals have a thick layer of fat under a hard and robust skin , which keep them isolated from these heat losses.when they live in very cold areas of the planet.Some marine mammals have hair, because certain vital functions are carried out outside the water, such as reproduction.
Those marine mammals that, in certain periods of their lives, inhabit the great depths, have developed other organs to be able to live in the darkness, like the sonar .The sense of sight in these ecosystems is not subtle, because sunlight does not reach that depth.
Like all mammals, these aquatic animals have mammary glands that produce milk for their offspring, sweat glands and gestate on their progeny inside their body.

Breathing of aquatic mammals
Aquatic mammals need air to breathe .Therefore, they take large amounts of air and keep it inside their lungs for long periods of time, when they submerge after taking air, are able to redirect blood to the brain, heart and skeletal muscle.Their muscles have a large concentration of a protein called myoglobin , capable of accumulating large amounts of oxygen.
In this way, aquatic animals are able to remain considerable periods of time without taking air.The young and newborn babies do not have this capacity developed, so they will need to take air more times than the rest of the group.
Types of aquatic mammals
Most species of aquatic mammals live in the marine environment.There are three orders of aquatic mammals: cetacea, carnivora and sirenia.
Order cetacea
Inside of the cetacea order, the most representative species are whales, dolphins, sperm whales, killer whales and porpoises .The cetaceans evolved from a species of terrestrial carnivorous ungulate more than 50 million years ago.The cetacea order Divide into three suborders (one of them extinct):
- Archaeoceti : predecessor terrestrial quadruped animals of the current (extinct) cetaceans.
- Mysticeti : they are whales with beards.They are carnivorous animals without teeth that take large puffs of water, then filter it through their beards and with the tongue collect the trapped fish.
- Odontoceti : Dolphins, killer whales, porpoises and zifios are included here.It is a very diverse group, although its main characteristic l is that they have teeth.In this group we can find the pink dolphin ( Inia geoffrensis ), a kind of mammal aquatic river.
Carnival order
In the carnival order, we include seals, sea lions and walruses , although they could also include to the sea otter and polar bears.This group of animals appeared about 15 million years ago and are believed to be closely related to mustelids and asses (bears).
Order sirenia
Elultimo order, sirenia, includes dugongs and manatees .These animals have evolved from the tetiteriums, animals very similar to the elephants that appeared about 66 million years ago.The dugongs inhabit Australia and, manatees, in Africa and America.

List of examples of aquatic mammals and their names
Cetacea order
Mysticeti:
- Greenland Whale ( Balaena mysticetus )
- Whale Southern right ( Eubalaena australis )
- Glacial free whale ( Eubalaena glacialis )
- Pacific free whale ( Eubalaena japonica )
- Common Rorcual ( Balaenoptera physalus )
- Rorcual sei or borealis (Balaenoptera borealis)
- Rorcual de Bryde (Balaenoptera brydei)
- Tropical whale (Balaenoptera edeni)
- Great blue whale or blue whale (Balaenoptera musculus)
- Aliblanco, dwarf or common minke ( Balaenoptera acutorostrata)
- Rorcual austral or Antarctic minke (Balaenoptera bonaerensis)
- Rorcual of Omura (Balaenoptera omurai)
- Yubarta or humpback whale ( Megaptera novaeangliae )
- Gray whale ( Eschrichtius robustus )
- Pygmy whale ( Caperea marginata )
Odontoceti:
- Tonina overa ( Cephalorhynchus commersonii )
- Heaviside dolphin ( Cephalorhynchus heavisidii )
- Coastal common dolphin ( Delphinus capensis )
- Pygmy killer whale ( Feresa attenuata )
- Calderon common ( Globicephala melas )
- Risso's dolphin ( Grampus griseus )
- Fraser dolphin ( Lagenodelphis hosei )
- Atlantic dolphin ( Lagenorhynchus acutus )
- Northern dolphin without fin ( Lissodelphis borealis )
- Common killer whale ( Orcinus orca )
- Hong Kong pink dolphin ( Sousa chinensis )
- Delfin listed ( Stenella coeruleoalba )
- Bottlenose or bottlenose dolphin ( Tursiops truncatus )
- Boto, Amazon dolphin, pink dolphin ( Inia geoffrensis )
- Baiji, Chinese river dolphin ( Lipotes vexillifer )
- Silver Dolphin ( Pontoporia blainvillei )
- Beluga ( Delphinapterus leucas )
- Narval ( Monodon monoceros )
Carnival order
- Seal Mediterranean monk ( Monachus monachus )
- Northern sea elephant ( Mirounga angustirostris )
- Leopard seal ( Hydrurga leptonyx )
- Common or harbor seal ( Phoca vitulina )
- Australian and South African sea lion ( Arctocephalus pusillus )
- Guadeloupe sea bear ( Arctophoca philippii townsendi )
- Steller's sea lion ( Eumetopias jubatus )
- California sea lion ( Zalophus californianus )
- Sea otter ( Enhydra lutris )
- Polar bear ( Ursus maritimus )
Sirenia order
- Dugongo ( Dugong dugon )
- Caribbean Manati ( Trichechus manatus )
- Amazonian Manati ( Trichechus inunguis )
- African Manati ( Trichechus senegalensis )
If you want to read more articles similar to Aquatic mammals-Features and examples , we recommend that you enter our Curiosity section It's from the animal world.
References
https://basicbiology.net/animal/mammals/marine
Bibliography
Irving, L.1973.Comparative Physiology of Thermoregulation.ACADEMIC PRESS, INC.2: 47-96.
Kramer, DL1988.The behavioral ecology of air breathing by aquatic animals.Canadian Journal of Zoology, 66 (1 ): 89-94.
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