The marine mammals are all those animal species that live in aquatic environments such as oceans and seas, but are not fish such but mammals with features to suit the water. To understand them better, we must talk about their nature: being mammals, they do not hatch from eggs; They are viviparous , that is, the female carries the babies within her to give birth to them after a gestation period.
They are carnivores , since they eat fish . Regarding their way of life, they can spend their whole life in the water or go ashore to spend time on land. This behavior is defined by their physical characteristics : those that spend their entire lives in the water have more fish characteristics, such as fins and an elongated body; on the other hand, those that go ashore have wider and more mobile bodies on land.
The fish have a flattened skeleton and are covered in scales that help the fins to break the tension of the water and transport themselves easier in the water. They also breathe through gills. For their part, marine mammals have a skeleton covered by a muscular system, a layer of fat to maintain body temperature, thick skin and a coat that covers it. Its respiratory system consists, as in the human, of the nose, trachea, lungs and their components.
Marine mammals are the result of a long evolution, in which terrestrial species have had to return to the sea frequently and have adapted to the water to feed or move. There are characteristics like the respiratory system that have not changed, of course, because they are mammals and mammals are configured that way. But they are able to alternate lapses in and out of the water . The blue whale, for example, comes out from time to time for air.
Types of marine mammals
Marine mammals are divided into two large groups:
- Cetaceans
- Sirenids
Cetaceans
Cetaceans have an appearance very close to that of fish, but they have some characteristics that distinguish them such as a horizontal tail , great intelligence and some of them are great predators. They are born in water and spend their entire lives there, surfacing from time to time for air. Among them are dolphins, belugas, blue whales, sperm whales, among others.
Sirenids
Sirenids are marine mammals that alternate their lives between water and land. When they enter the sea it is to cool off, hunt for food or move to another safer and more comfortable place. They have a more robust body than cetaceans, and have fins that help them to transport themselves both on land and in water. They communicate by roaring and screaming. Among the Sirens are seals, walruses, sea lions, among others.
20 examples of marine mammals
- Dolphin (cetacean)
- Blue whale (cetacean)
- Gray whale (cetacean)
- Sperm whale (cetacean)
- Beluga (cetacean)
- Greenland whale (cetacean)
- Orca (cetacean)
- Narwhal (cetacean)
- Fin whale (cetacean)
- Glacial right whale (cetacean)
- Caribbean manatee (siren)
- Amazonian manatee (siren)
- African manatee (siren)
- Dugong
- Gray seal
- Elephant seal
- Leopard seal
- Monk seal
- Walrus
- Sea lion
