It is no secret that the seas and oceans are places of distribution and habitat of the most unusual, beautiful and simply amazing animals. The fauna of the oceans and seas still presents surprises to researchers. Discoveries of incredible animals are made, their lifestyle and interactions are studied.
Among marine and oceanic inhabitants there are representatives of all classes of animals, except perhaps birds. And then, depending on what point of view you should look at them. Indeed, many birds hunt in the water, and penguins generally live in the ocean. But in this article I would like to dwell specifically on those who fit the definition of "marine mammal".
Fauna of the seas and oceans
The organoleptic and chemical composition of water in the seas and oceans are almost the same. Water differs only in the content of certain elements and in the concentration of salts. Therefore, their fauna is also extremely similar. Animals of the seas easily go into the ocean, and animals of the oceans feel great in the seas.
The fauna of these reservoirs is represented by animals of the following classes:
- Shellfish of all kinds.
- Crustaceans.
- Fishes.
- Polyps.
- Sponges.
- Hydroid.
- Insects.
- Amphibians.
- Reptiles.
- Mammals
- Birds.
It is obvious that the organic world of oceans and seas is extremely diverse and large in biomass volumes. Among all the fauna, a marine mammal deserves special attention. Most often, they live simultaneously on land and in water. However, there are also purely aquatic inhabitants.
Species diversity of mammals in the seas
The species of mammals living in the seas and oceans is very interesting and diverse in terms of lifestyle and appearance. Consider the main representatives.
- Whales. They include different species: blue, gray, Greenland, sperm whales, humpback, beaked, minke whales and others.
- Killer whales. Very close to whales animals, dangerous killers of sea and ocean expanses.
- Dolphins. Different species: bottlenose dolphins, beak-headed, short-headed, porpoises, beluga whales and others.
- Seals. Animals of the genus of seals, the most common - ringed seal.
- Seals. They include several varieties: lionfish, spotted seals, eared, real, lahtaki and others.
- Sea elephants of two species: northern and southern.
- Sea lions.
- Sea cows are today a mammal that has been practically exterminated by humans.
- Walruses.
- Seals.
In total, there are over 120 species of diverse marine mammals.
Signs of mammals
Like land species, marine and ocean animals also have distinctive features that can be classified as mammals. What animals are mammals?
- Like all representatives of this class, marine and oceanic mammals are characterized by feeding their offspring with milk through special mammary glands.
- These animals bear offspring within themselves (intrauterine development) and reproduce it through the process of live birth.
- These are poikilothermic animals (warm-blooded), they have sweat glands, a thick layer of glycogen subcutaneous fat.
- A diaphragm is available for breathing.
These devices make it possible to reliably attribute all of the above animals to marine and ocean mammals.
Features of the lifestyle of marine animals
Animals of the seas and oceans have a number of devices in order to feel confident and safe in the vast expanses of water. For example:
- limbs converted to flippers for quick movement;
- many of them have powerful sharp teeth (predators and carnivores);
- large body sizes with a thick layer of subcutaneous fat;
- streamlined body shape, increasing speed;
- the ability to give each other sound signals (for most).
Thanks to such adaptations, marine animals of the ocean coexist perfectly with each other and the surrounding world. Most often, the mammals of the seas try to stay herd. This is characteristic of those who cannot protect themselves from large predators other than flight (fur seals, otters, seals, lions, seals).
Others, on the contrary, prefer solitude. This is more convenient for hunting and stalking prey (sperm whales, killer whales, predatory species of dolphins and whales).
The ability to transmit sound signals to each other is very important. So you can warn of danger and protect yourself in time. In addition, you can share food with relatives.
The lifestyle of marine mammals with rare daily exceptions. At night, they usually relax. However, there are exceptions (some species of whales, seals are nocturnal).
Seabed mammals
A mammal is a marine animal that moves along the very bottom of the depths of the oceans and seas - dugong or sea cow (siren). This animal is completely harmless, it fully lives up to its name, as it feeds exclusively on the bottom vegetation.
The sizes are average compared to the rest of the mammalian seas: about 4 m in length, weight about 600-650 kg. A person can calmly swim next to the sea cow and even touch it, stroke it. The animal is very affectionate, obedient and harmless, like a child.
In addition, this animal is one of the oldest on our planet (appeared about 50 million years ago), it is listed in the Red Book. This is perhaps the only representative belonging to the category of "animals of the seabed."
The remaining representatives of marine mammals prefer to spend time near the surface or in the water column, rarely sinking to the bottom.
The most dangerous animals of the oceans
The most dangerous ocean animals include:
- Killer whales (killer whales). Weigh more than 8 tons, reach a length of 10 m. Ruthless killers feeding on large fish, mammals and their own relatives - whales.
- Sperm whales. They attack squid, octopus and giant clams, can eat large fish. The weight of the animal is about 50 tons, and the length is over 20 m.
- Sea lions. In appearance, cute and completely harmless animals often attack a person, as they strictly guard their possessions. In addition, they are carnivorous and feed on fish, small animals.
Of course, there are still many dangers in the oceans. However, among the mammals of the marine fauna, the above are the most dangerous. The rest are either herbivores or feed on plankton or small animals.
The largest animals of the oceans
The largest representatives of the largest mammalian animals are:
- Blue or blue whale - in length reaches 33 m. Its weight varies from 90 to 120 tons. The heart of this whale alone weighs over 600 kg!
- Southern elephant seal - up to 6 m in length. Weight from 5 to 6 tons. In addition to their grandiose size, these animals are also predators - dangerous and ferocious. They are able to immerse themselves in water to a depth of over a thousand meters if they set themselves the goal of catching up with the victim at all costs.
- Walruses reach a length of 4 m and weigh up to 2 tons. Very impressive dimensions for a completely harmless nature - they feed on small invertebrates, tearing them out of silt and sand at the bottom of the coastal zones. Big dormouse spend a lot of time in group sleep on the banks of ponds.
The most harmless animals of the seas and oceans
What are the names of marine animals, which are the most harmless mammals of the sea and ocean? The answer is known to every student: of course, bottlenose dolphins! Lovers of swimming with people, friendly and beautiful - they rejoice and play, splash, jump (up to 6 meters high!) And bring a lot of fun and pleasure to people.
Also harmless marine animals include seals, otters, fur seals and some whales.