From the time we were educated at school, everyone knows that fish are cold-blooded animals. And not everyone knows that some representatives of aquatic inhabitants are not cold-blooded. The article will introduce you to these exceptional animals and the benefits of their existence, and a photo of warm-blooded fish will visually complement the information presented.
Cold-bloodedness as a way of life
To understand all the features of warm-blooded fish, it is necessary to highlight the main points associated with the cold-bloodedness of most representatives of this class. This term means that in such animals the body temperature is not constant and varies depending on this indicator in the environment and space. This is expressed in the fact that in a habitat with a high temperature, the activity of such animals is higher, and the speed of movement is also higher. The reason for this is increased energy production, which allows the muscles to work harder.
In cold weather, fish are calm and slow, their metabolism slows down. This is wherea danger to them, because if the temperature remains low for a long time, this can lead to the death of the animal. To avoid this, fish descend into warmer and deeper waters, and certain species have a special protein in their blood with antifreeze properties.
Warm-blooded fish
This concept is associated with the ability of a living organism to maintain a constant body temperature, regardless of the ambient temperature. And yet there is a difference between a fish and, for example, a bird, which have this same feature. The latter have an excellent circulatory structure and maintain a regular temperature mainly due to the self-generation of energy from the food they consume. Warm-blooded fish use a different mechanism to increase body heat, based on muscle contraction and subtlety in the process of regulating blood flow.
Scientists from America discovered the first exceptional specimen on May 15, 2015. At the moment, the list of warm-blooded fish is small, only three representatives. But the research is not over, so new names can be expected. In the meantime, consider the features of the three already available.
Moonfish, or redfin opah
These are magnificent, large and deep-sea fish that can dive almost 500 meters into the world's oceans. They feed on squid and small fish. The body of the opah is very large in height and strongly flattened laterally. The length of this fish varies from one and a half to two meters, and its approximate weight is about 50-60 kg. Very dynamic fluctuations of the pectoral fins contribute to maintaining the body temperature of the opah greater than the temperature in the water. And fish can keep warm thanks to a large layer of adipose tissue and the peculiar structure of blood vessels in the gills. This allows the opah to navigate perfectly, as well as react with lightning speed to what is happening around. It is this fish, as a warm-blooded animal, that is considered complete, unlike the others listed below.
Skipjack or skipjack tuna
Stripe tuna is a large fish with a thick and rounded body up to 100 cm long (in rare cases it exceeds one meter). Its diet consists of small fish, crustaceans and squid. Intensely contracting muscles help heat the body, and the cooling process is controlled by the peculiar structure of the circulatory system. Warm-bloodedness allows massive tuna to move at high speed, making them quite dangerous hunters. Tuna meat is highly valued in the culinary world for its firm, meat-like texture and he alth benefits.
Some types of sharks
Consider the following types:
- Mako shark. The weight of these creatures can reach up to 400 kg. The body is about 3-4 meters long, elongated, which makes it possible to move very quickly in the water. The color of this species justifies its second name, such as the "blue-gray shark": dark blue on top and almost white on the abdomen. With such a shade, this predator is not noticeable at allat depth, and it helps a lot to hunt for food.
- Blue shark. This species has a typical appearance for a member of the family, has prominent pectoral fins that exceed the standard length. The approximate weight of this predator is approximately 130-180 kg. Very elongated, oblong and pointed muzzle. The fastest speed this predatory fish can develop is 40 km/h.
- Great white shark. This is one of the largest predators on the planet. This fish got its fame as a man-eating shark for a reason: a very large number of attacks on people have been recorded. In size, it surpasses even killer whales, can reach a length of 12 meters. This predator has the largest teeth of all currently existing fish (5 cm). White sharks feed mainly on crabs, fish, shellfish and small marine animals.
The body of all these warm-blooded fish is heated due to increased muscle contraction, and the body temperature is approximately 7-10 degrees higher than the water temperature. When there is a transition to cooler waters, these particular sharks can control the blood supply to the internal organs. Blocking blood flow to the least important parts of the body helps to rationally waste precious heat.
