The frequent occurrence of whale stranding events around the world makes it a key factor for the continuous decrease of whale population. Environmentalists and scientists believe that environmental pollution causes whales to run aground, and chemicals that pollute seawater may disturb whales' feelings.
In addition, the sound waves emitted by the sonar and echo sounder of warships and the noise of underwater explosion will make the whale's echo positioning system disorder, thus stranding the frightened whale.
2. Global warming
Rising ocean temperatures have reduced the environment suitable for cetaceans. Climate change leads to the change of whale habitat environment, thus reducing its food source. Therefore, in recent years, a large number of whales are threatened by hunger.
3. Human cruel "killing"
Today, whaling is still rampant. Although the International Whaling Commission announced the prohibition of commercial whaling in 1986, the world has not stopped killing whales. Japanese whaling ships continue to engage in whaling activities under the guise of scientific research.
At present, this kind of whaling in Japan has reached the point of "crossing the street mice, everyone cries out", but Japanese businessmen, driven by commercial interests, turn a deaf ear to the resistance of environmentalists around the world.
Whaling and anti-whaling operations are a protracted war. Looking back on this operation that lasted for half a century, although some achievements have been made, it is a pity that the number of whales has not recovered significantly. After several ups and downs of whaling, the figure of whales is gradually disappearing into the depths of the sea.
Extended data:
Blue whales breed in winter, and females are usually born every two years. Pregnancy 10- 12 months, each fetus only gives birth to 1 child. This calf weighs about 2.5 tons and is about 7 meters long. In order to prevent suffocation, the mother beast should lift her cub out of the water to take the first breath of air, and then she can breathe by herself.
A pair of nipples of female animals grow on both sides of reproductive foramen, and swim in the upper layer of seawater when breastfeeding, and the cubs follow closely below the tail of female animals. Because the larvae have no movable lips, they can't hold their nipples to suck milk. Female animals directly spray milk into their mouths by virtue of muscle contraction, which is also a good adaptation to life in water.
Blue whale's milk is rich in nutrition, in which the fat content is 10 times that of milk, and the milk that young whales suck every day is above 1000 kg, so it develops rapidly. After 8 months, it can be increased to 65,438+05 m and its weight can be increased to 23,000 kg, so it can eat all kinds of plankton with its own mouth.
By the age of two and a half to three, the body length can exceed 20 meters. The age of sexual maturity is about 8- 10 years old, and the life expectancy is generally over 50 years old, with the highest being 90- 100 years old.
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