How much do you claim to know about the sea and sailing? Here are some facts that only the real sailors know.
1. Why do seagulls like to chase boats?
When sailing on the vast sea, there will always be a picture of a group of seagulls surrounding the accompanying sailboat. This scene is always full of vitality and poetry. In fact, the reason why seagulls love chasing sailboats so much is not because they like humans, but because when the ship sails at sea, due to the resistance of air and sea water, an updraft will be generated above, seagulls can drag their bodies to fly with the help of updrafts to save energy. Secondly, the waves caused by the boats breaking through the waves will make the small fish and shrimp dizzy and float on the water, and the seagulls with strong eyesight can easily catch them.
2. Why isn't fish meat as salty as sea water?
Sashimi can be said to be one of the favorite dishes of sailors who often floating in the sea. But have you ever wondered why the sea water is so salty, but the fish that live in the sea are not? In fact, the salt content of fish is only one-third of that of sea water. Like most animals, excessive salt absorption can cause fish to be dehydrated, even in sea water. Therefore, fish must drink a lot of water. After the intestinal tract absorbs the water, the salt is excreted through the fish gills or urine. Therefore, the higher the salt in the sea area they are in, the more water they drink.
3. Will thunder at sea electrocute marine life?
First, lightning does not often occur at sea, which is related to the high specific heat capacity of water. Even if there is an occasional lightning strike, seawater is a good conductor of electricity, and it will instantly spread the current along the surface of the ocean and will not extend to the active areas of marine life such as fish, and the electricity on the surface of the seawater has become very weak at this time. Unless the fish swim too close to the surface, they are basically safe. Some people will ask, if the fish under the sea are safe, are the sailboats floating on the sea safe? Don't worry, modern sailboats are equipped with lightning protection devices, and most people will not go out to sea in thunderstorms.
4. Are all fish cold-blooded?
Yes, but not all. Fish are cold-blooded animals with low body temperature. They adjust themselves to the temperature of the sea and find the environment they are most comfortable with. However, like humans, they also generate heat energy during metabolism, which can raise their body temperature slightly, but the difference is not much from the water temperature in their environment, at most only about 1°C higher. The only known warm-blooded fish in the ocean, the sunfish, generates heat by constantly flapping its wing-like pectoral fins, and its muscles are on average 4-5°C warmer than the surrounding seawater. This unique body structure ensures that the sunfish can become the warmest existence even in icy waters.