Dolphin is fish or mammal?
Probably, many at one time wondered: is a dolphin a fish or a mammal? Indeed, like many representatives of fish, he lives in the oceans and seas and leads a lifestyle similar to them. However, dolphins are aquatic mammals that belong to the class of cetaceans.
The relatives of this animal are whales and killer whales. ancient, at the moment already extinct progenitors, are considered predators. sea otters, which, like dolphins, lived in the water.
A little-known but highly-debated side of how intelligent these animals are. Almost all life of a mammal is free time, when they can do whatever they want. He spends it on fun games, communication and even sex. Mammals love to jump out of the water, twirl and twist in every possible way. Despite their carefree existence, dolphins are considered very intelligent mammals, because they are able to communicate, think, follow commands, even save people.
The animal’s brain, in the ratio of body proportions, is large, and if compared with monkeys, dolphins have much larger. Also, thanks to research by scientists, it was revealed that the mammal has a very developed vocabulary. Not to mention self-awareness, emotional empathy, social development, mutual support and mutual assistance.
It should also be said about how they catch their prey. First, a flock of dolphins use their main weapon. echolocation, scanning the water for fish. Further, if a school is detected, they approach with great speed, while giving such sound signals at which the fish panic and get lost in a compacted heap. This is where smart mammals know their stuff. Together, they catch their prey. The possibilities for such a hunt are great. Mammals are able to catch almost the entire school of fish.
Skin and color of a mammal
The color of the animal can be varied.
- Solid (gray, pink, black).
- Bicolor (black and white shades).
These mammals are very nimble and energetic, they move in water at high speed, which causes the upper layers of the skin to wear out. Therefore, dolphins have a deep layer of skin, which is constantly renewed. This process is very fast, the upper and lower layers change during the day. Skin cells are constantly dividing, and about 30 layers of skin can change in a day. Continuous molting is the main condition of these intelligent mammals.
The main features of a mammal
This type of animal is diverse, extensive and there are about 50 different species. Dolphins are ancient mammals that are of great interest to humans. They are called intelligent and understanding beings.
Dolphins’ appearance is somewhat unusual for a marine life. On its body there are no scales, like fish, on the contrary, its cover is streamlined and slippery, so the animal is well adapted both to the depths and to the surface of the waters.
Description and characteristics of dolphins:
- These mammals are flexible, muscular and very nimble. Unlike common fish, dolphins have unusual fins at the bottom and on the back.
- The head is medium in size. The muzzle has a sharp point, on which the transition from the frontal to the nose is clearly expressed.
- The mammal has poor eyesight. The animal has small eyes that do not prevent it from tracking prey.
- These mammals lack nostrils. The animals have adapted to the water quite well, so they do not need a nose opening. The “breathing” through which the mammal receives the necessary air is located on the parietal part. It is this hole that is responsible for ensuring that the animal can breathe under water.
- There are no ears as such. This is clearly visible with the naked eye, but despite this, animals have excellent hearing.
- The mammal has echolocation. Thanks to such abilities, the animal can easily determine the location of the object, due to the sound wave. The sound they make can be compared to a crackling, chirping, clicking. The whistle is also unique and diverse. Each sound is a specific action, thought. Also, during experiments, it was revealed that intelligent dolphins are able to assign and recognize names.
- Dolphins have small teeth. There are about 60 of them in the oral cavity.
Pregnancy in a female lasts from 10 to 18 months. Usually, a baby is born about 60 cm long, tail out. The newborn is so developed that from the very first minutes it begins to follow the mother. Studying in its flock, the animal grows smarter, develops, learns to hunt fish, communicates and soon gets its own food.
The most bitter enemies of the dolphin, like all the inhabitants of the ocean, are considered to be the shark, as well as some relatives of the mammal (killer whale). Since ancient times, people have also begun to hunt dolphins. The indigenous people of the north caught mammals and extracted only meat. This is a high degree of cruelty. Currently, in some countries, the barbaric tradition of hunting dolphins has remained.
These mammals die due to human activities. Animals often end up in fishing nets. Die from oil spills at sea. The wounds caused by the propellers of ships affect the life and death of dolphins. All this is facilitated by a person, even if unconsciously, but he made a lot of efforts that contribute to the destruction of dolphins. But some of them are already listed in the Red Book.
Dolphinariums, water parks with complex animal training, all contribute to the destruction of these intelligent mammals. It’s worth thinking about.
Salmon are typical anadromous fish that prefer to live permanently in lakes or seawater. They go to rivers only to spawn. Different breeds of red fish have similar types of activity, but differ in basic characteristics.
After reaching the age of five, salmon move into the water with a fast current. It can enter river waters at different times. Before spawning, fish choose special sites. They can be found in places with not very fast currents, shallow depths, rocky or sandy ground. Similar areas can be found near spawning grounds, rapids and rapids.
In seawater, salmon can develop an impressive speed. Some individuals are able to overcome up to 100 km per day. When released into the river, these indicators are significantly reduced. While staying in such areas, salmon lose their bright colors, and a peculiar hook forms on its jaw, which is especially pronounced in males. Fish fillets are paler during this period. The percentage of adipose tissue is also reduced. This is due to lack of nutrition.
Almost all anadromous salmon spawn once in a lifetime and die after spawning.
Adults have a body length of up to 2 m, their maximum weight ranges from 68 to 70 kg. In terms of body structure, they resemble representatives of herring. It is noteworthy that it was to this order that all salmonids were once ranked, but later they were singled out as an independent order. Salmon looks like this:
- Long body, laterally compressed;
- Ridge scales are round;
- Pelvic fins in several rays, localized in the central part of the belly;
- Dorsal fins (real and anal).
According to the description of the detachment, the presence of the so-called adipose fin of miniature size is characteristic of salmonids. The dorsal fin may have 10-16 rays. For comparison, grayling has an average of 20 rays. The swimbladder is usually connected to the esophagus through a special duct.
The oral cavity is protected by four bones. In females, during the breeding season, eggs easily move from the ovary to the body cavity. The intestine has an impressive number of pyloric branches. Most of the family members have transparent eyelids. The skeletal part in many species is not completely ossified.
Most salmon are valuable commercial fish due to their red meat and red caviar.
Sesame, which lives in the Russian Baltic, the Black, White and Aral Seas, is also called taimen salmon.
It is an anadromous fish that goes to spawn in the rivers of European countries. In length, it usually reaches 40-70 centimeters, and weighs two to five kilograms. However, some especially large individuals of brown trout can be found weighing up to 15 kilograms.
It is a popular commercial fish appreciated for its tasty and healthy meat. The brown trout is distinguished by a rather changeable lifestyle: it spawns mainly in the upper reaches of rivers, does not differ in migrations over long distances, and loves fresh water, in which after birth it spends several years.
The trout found in the Black and Azov Seas are otherwise called Black Sea salmon.
This small representative of the salmon family is found both in fresh water bodies and in salty seas.
Basically, whitefish live up to 7-10 years, but some representatives of whitefishes are long-livers. they live up to 20 years and reach a length of about 50 centimeters.
It is a silvery fish with dark fins. It is customary to distinguish several dozen species of whitefish, many of which differ little from each other. However, there is one clear difference between whitefish and fellow salmon: the meat of this fish is white.
List of fish
- Noble salmon. This fish is most often called salmon. This is a large fish, reaching a length of one and a half meters. Its weight is up to 40 kilograms. The Far Eastern salmon has a silvery color, only on the sides, just above the midline, there are several dark spots that form the letter “X”. On the sides, the scales have a bluish tint.
- Pink salmon. It is very easy to distinguish it from other representatives of this genus by its small silvery scales and by the presence of many specks near the tail. During spawning, it changes color and appearance. Females become dark in color, while males develop teeth and a hump on their back. The fish are no more than seventy centimeters long. Lives in the Pacific and Atlantic Ocean. The caviar is large, maybe 8 centimeters in diameter. After spawning, she dies.
- Chum. She is the most famous among fish. Differs in a silvery color without spots. During the spawning period, it changes color to dark. It is found in the Pacific Ocean, and goes to reproduce in the upper reaches of the rivers of Siberia. There are two types of this fish: autumn (its length is 1 meter) and summer (length. no more than eighty centimeters).
- Red salmon. It is found in the Pacific Ocean, however, it is not very popular, since the fishery is carried out off the coast of Asia and Alaska. The fish is distinguished by a significant number of gill eggs, a bright scarlet shade of meat. There are two types that are associated with the spawning period: in spring, in summer or in autumn.
- Coho salmon. It is also found in the Pacific Ocean, and goes to reproduce in the waters of North America and Asia. The fish has a silvery color, which is why it is called silver salmon. Its length is no more than sixty centimeters, however, you can find individuals whose length can be eighty centimeters. During breeding, it changes color to bright crimson.
- Chinook salmon. The most valuable and largest species of the salmon family. A fish can weigh up to fifty kilograms, with a body length of ninety centimeters. It is distinguished by pronounced gill stripes, of which it has at least fifteen pieces. It is found off the coast of North America, but comes to the shores of the Far East for breeding. She has healthy red meat.
- Brown trout. It is found in the Baltic, Black and White seas. It is also called taimen. Its length is no more than half a meter, and its weight is no more than five kilograms. Trout has tasty and nutritious meat. Breeds in the upper reaches of rivers, in fresh water.
- Whitefish. This is not a very large representative of the family, which is found in both salt and fresh water bodies. Differs in silvery scales and dark fins. Whitefish are divided into subspecies, which do not differ in any way in appearance. His meat is white.
- Nelma. It belongs to the whitefish family, but unlike other representatives of this subspecies, it can be up to one and a half meters long, with a weight of about thirty kilograms. Loves fresh water and is found most often in northern rivers.
- Taimen. This fish is divided into common, Sakhalin, Korean and Danube taimen. The difference is in appearance, it is related to the habitat. The common taimen differs from the Danube taimen in the number of stripes on the gills. Sakhalin can be up to a meter long, while weighing thirty kilograms.
- Lenok. Differs in black with a yellow tint. His caviar is small. Lenka looks like a whitefish. Dwells in fresh water.
- Trout. It is found in freshwater lakes such as Onega and Ladoga. Occurs in Karelia and in the White Sea and Baltic basin. Depending on the habitat, brook and lake trout are distinguished. Loves fresh clean water. over, it has an unusual color. It is distinguished by delicious meat, therefore it is in high demand among fishermen. Can be bred in both natural and artificial reservoirs.
- Ishkhan. It is found in Lake Sevan and is translated as “prince”. Usually it is silvery in color, but during the spawning period it turns black, with bright scarlet spots on the body. Some individuals can weigh up to fifteen kilograms, however, average sizes: thirty centimeters in length, with a weight of no more than a kilogram.
The salmon family has a large variety of fish that are valued for their excellent taste. All of them are in demand among amateur fishermen and sportsmen.
Classification of varieties
Salmon include a large number of different fish, united by separate characteristics and differing. The family is represented by 3 subspecies:
- Whitefish. Includes 3 kinds.
- Actually salmon. Combines 7 genera.
- Grayling. Includes 1 genus.
In size, all members of the family have a large or medium body. Many are predators, but at the same time, representatives with a mixed type of diet are found. List of names of the main salmonid fish species:
- Pink salmon;
- Coho salmon;
- Red salmon;
- Steelhead salmon.
The Whitefish family differs from the salmonids proper in the structural features of the cranium, larger scales, and a small mouth. Grayling has a high dorsal fin with an impressive length. It can be brightly colored and resemble a train in appearance. Grayling is freshwater. Far Eastern salmon, salmon and ishkhan are considered the most valuable varieties.
Pink salmon is the smallest and most common representative of the salmon genus.
The salmon family, in addition to two genera of salmon, also includes taimen, lenok, grayling, char, whitefish and palii. But, again, here we are talking only about salmon. Pacific (Oncorhynchus) and noble (Salmo). Below is a brief description and the main differences between these genera.
Pacific salmon (Oncorhynchus). This group includes the pink salmon, chum salmon, coho salmon, sima, sockeye salmon, chinook salmon and several American salmon living in our waters. Representatives of this genus spawn once in a lifetime and die immediately after spawning.
Sockeye salmon is the brightest representative of the Far Eastern salmon
Noble, or real salmon (Salmo), unlike their Pacific counterparts, after spawning, as a rule, do not die and can reproduce several times during their life. This group of salmon includes the well-known salmon and many species of trout.
Is there a salmon fish?
Quite often people are interested in what kind of fish it is. salmon. Let’s immediately determine that salmon is any fish from two genera of the salmon family (Salmonidae). the genus of Pacific salmon (Oncorhynchus) and the genus of noble salmon (Salmo). Sometimes the word “salmon” is directly included in the trivial names of some of these fish species, for example, steelhead salmon. mykiss (Oncorhynchus mykiss) or Atlantic salmon (aka noble salmon). better known as salmon (Salmo salar). Perhaps, it is salmon that is most often called simply salmon, meaning a specific species.
Salmon is different
The word “salmon” itself comes from the Indo-European word lax and means “spotted”, “speckled”. Until the 16th century, the word “salmon” in Russian was feminine, now it is masculine. The name of the salmon family. Salmonidae. comes from the Latin root salio. to jump and is associated with spawning behavior (details below in the section Reproduction and migration of salmon).
Representatives of salmon are found both in the seas and oceans. the Pacific and Atlantic, and in fresh water bodies. They are found in large numbers in Europe and North Asia, in fresh water bodies in the north of the African continent and the North American continent.
Note: salmon live in the wild exclusively in the northern hemisphere of the earth. But in the southern hemisphere, representatives of this family can be found only in artificial reservoirs and on fish farms.
In the Russian Federation, salmonids are often found in the Far East. off the coast of Kamchatka, the Kuril Islands, near Sakhalin. Fishing for these types of fish is organized here.
Salmon fishing and breeding
All salmon are valuable commercial fish. Anadromous salmon are harvested in the sea, as their meat loses a part of its taste during the transition from salty sea water to fresh water. As an object of amateur salmon, in my opinion, the most interesting fish.
Thanks to the tradition of salmon returning to their native river (homingu) for spawning, salmon are bred in fish factories. The fish factory is usually built on the river. The fish going to spawn are caught, the eggs are taken and fertilized. Fry eggs obtained after incubation are reared and released back into the river. The fry slide into the sea, feed up and return to their native river after a year or several years. Thanks to this approach, the survival rate of juvenile salmon increases significantly.
Residential (freshwater) forms of salmon, such as trout, are reared in fish farms from the time of fertilization of eggs until the adult fish is ready for sale.
Actually, that’s all. Now you know who salmon are and what they are. I bring to your attention a short educational video about the life of salmon.
Is a fish a mammal or not? Characteristics of marine life
“Is a fish a mammal or not?” Is one of the frequently asked questions. In order to answer it, we will consider this definition in more detail, get acquainted with the characteristics of various marine life. From today’s text, you can find out exactly which creatures belong to mammals, which ones live in the water and how they look.
Mammals in the sea: unusual facts
Several unusual facts about marine mammals can be noted:
- All marine mammals can be under water without oxygen for a certain time. For example, whales can survive without air for about 35 minutes, while sperm whales can do without oxygen for up to 1.5 hours. The amount of time an animal can stay underwater is influenced by the size of its lungs. Hemoglobin in the blood also matters.
- The blue whale is the largest animal not only among marine life, but also among mammals on land (they were even entered in the book of records). However, whales do not pose a threat to humans because they have missing teeth.
- Larga seals are among the most abundant marine mammals. They can often be found even at a long distance from the coast, where they are used to hunting. Sometimes these animals create entire coastal settlements, where they live for a long time.
- The most dangerous creature is the killer whale. Yes, it does not attack humans, but it actively exterminates whales. In addition, killer whales are able to hunt dolphins, fur seals and even elk swimming across the sea straits. They are even able to turn over the ice floe with the size of their body, on which various marine life are swimming. As a rule, only males make attacks. for this they have to ambush their victims.
Killer whales are classified as dangerous marine predators
Singing whales. Toothed whales
Another group is represented by toothed whales, which have about 235 cone-shaped teeth in their mouths. they use them to catch prey. Famous representatives of this group are dolphins and sperm whales.
Representatives of this detachment are all the time only in the aquatic environment and do not get out on land. The rear fin and limbs (front), which have evolved into fins, allow them to swim. The hind limbs of these creatures are absent, but once they were. Experts were able to understand this from two characteristic protrusions that are located in the pelvic region.
The offspring of cetaceans are born strong, full-fledged. the cubs can immediately follow the adult, independently orient themselves in space.
The sperm whale belongs to the group of toothed whales. It has an oblong body, the length of which is 20 meters for males and about 12 meters for females. The average weight of animals is 75 tons. A distinctive feature is the massive head, which occupies a third of the entire body.
With such an abundance of teeth, the sperm whale is not a predator. it uses various mollusks, for which it has to dive to a depth where the animal stays for about an hour.
In the sea, you can also find creatures with similar characteristics. Animals spend most of their lives in water, and only a short time on land (some never leave the water at all). This group includes dozens of species of cetaceans, sirens, seals, pinnipeds, walruses. there are about 130 species in total, which is about 2.5% of all individuals of this class.
According to experts, ungulates are the progenitors of whales and sirens. Meanwhile, pinnipeds could have descended from the most ancient representatives of the class of canine.
Killer whale is one of the most beautiful inhabitants of the water element
over, cetaceans and horned mammals lived in the ocean even before the appearance of mankind. This fact is proved by paleontological studies, thanks to which it became known that seals existed even more than 25 million years ago. In the course of evolution, these animals changed, some of them died. Others, on the contrary, were able to adapt to new living conditions, increased in number.
There is a huge variety of marine mammals. They all have a certain appearance and differ in their way of life. Below we will consider the most famous representatives.
Table 1. Common mammals living in water
All these creatures are classified as mammals precisely because they are able to feed their offspring with milk. In addition, they are viviparous, which means that they carry young in the womb. Since they are warm-blooded creatures, they have a perspiration system and a subcutaneous fat layer. They breathe thanks to the presence of a diaphragm.
Due to such features, such creatures are classified as mammals, and not fish, despite the fact that many of them spend their entire lives in the water.
Who are mammals?
Mammals are individuals that feed their offspring with milk, which is produced by glands located in the thoracic region. It is the presence of these glands that is the main feature of animals of this species. These are vertebrates, warm-blooded creatures that have a brain on their back.
Fish do not feed their young with milk, therefore they cannot belong to this group. However, there are many other mammals in the marine environment.
Mammals are found among the inhabitants of the water