The origin of all living things on the planet occurred in the aquatic environment. Throughout the history of evolution, mammals have been changing and adapting to the conditions of the Earth’s surface until, several million years ago, some of them again plunged into oceans and rivers, adapting to life in these conditions.
In this article by Animal Expert, we will talk about aquatic mammals, better known as marine mammals, because it is in the seas that the greatest number of species of this type live. Learn about the characteristics of these animals and some examples.
- The life of mammals in water is very different from that of terrestrial mammals.
- To survive in this environment.
- They had to acquire special features during their evolution.
Water is a much denser environment than air and also offers greater resistance, so aquatic mammals have an extremely hydrodynamic body, allowing them to move easily. The development of fish-like fins represented a significant morphological change, allowing them to increase speed, swim directly and communicate.
Water is an environment that absorbs much more heat than air, so aquatic mammals have a thick layer of fat under hard, strong skin, keeping them insulated from these heat losses. In addition, it serves them as protection when they live in very cold areas of the planet. Some marine mammals have hairs because they perform certain vital functions outside the water, such as reproduction.
Marine mammals that, at certain times in their lives, live at great depths, have developed other organs to be able to live in darkness, such as sonar. The sense of sight in these ecosystems is useless, because sunlight does not reach this depth.
Like all mammals, these aquatic animals have sweat glands, mammary glands, which produce milk for their young and gesture their young inside the body.
Aquatic mammals need air to breathe. As a result, they inhale large amounts of air and keep it in the lungs for long periods of time. When submerged after breathing, they can redirect blood to the brain, heart, and skeletal muscles. Your muscles have a high concentration of a protein called myoglobin, capable of accumulating large amounts of oxygen.
In this way, aquatic animals can remain for considerable periods of time without breathing. Young and newborn puppies have not developed this ability, so they will have to breathe more often than the rest of the group.
Most species of aquatic mammals live in the marine environment. There are three orders of aquatic mammals: cetaceans, carnivores and mermaids.
Within the order of cetaceans, the most representative species are whales, dolphins, sperm whales, orcas and porpoises. Cetaceans evolved from a species of terrestrial carnivore ungulate more than 50 million years ago. The order of cetaceans is divided into three sub-orders (one of which is extinct):
Seals, sea lions and walruses are included in the carnivorous order, but may also include sea otters and polar bears. This group of animals appeared about 15 million years ago and is believed to be closely related to mustelids and bears.
Sirenia order
The last order, sirenia, includes dugongs and manatees. These animals evolved from tetiteria, animals very similar to elephants that emerged about 66 million years ago. The dugongs live in Australia and the manatees live in Africa and America.
Mysticeti:
Odontoceti
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