Dolphin corpse beach
Over the past decade, hundreds of dolphin carcasses have appeared on the beaches of the North Sea in the Netherlands, Belgium, Britain and Europe. The dead finless porpoise lying on the shore is terrible. Most of their faces were torn, their skin was cut, and their muscle tissue and fat were bitten.
These dolphins have strange stab wounds on their heads. There are 3 ~ 5 parallel scratches next to the wound, unlike those left by a shark bite. So who is such a cruel "murderer"?
Such frequent and cruel killing of finless porpoises has also attracted the attention of marine biologists, and more and more researchers have joined in the search for the real murderer.
Who would treat the finless porpoise so cruelly?
Eleven years ago, the bodies of two young male dolphins appeared on the beach in Belgium. At first, the investigators thought that the fishermen nearby had caught it by mistake, but after examining the bodies, they found that the wounds on the finless porpoises were not cut by fishing nets or engines, so the deaths of the two finless porpoises were not directly related to the fishermen nearby.
Scientists have turned their attention to marine animals that can prey on porpoises. Could sharks, killer whales and other animals prey on porpoises? Although there are sharks and killer whales in this sea area, it is not the two from the wound analysis. Scientists then discovered the key features of the wound. The dolphin had a pair of short, parallel and curved stab wounds on its head, which were obviously left by canine mammals.
The fox is not the murderer.
As a result, the fox who often walks by the sea becomes a suspect. Foxes are canines, with canine teeth, which fit the characteristics of wounds.
But after further study, it was found that the bodies of these dolphins were found when they washed ashore early in the morning, and the fox was Nocturnal Animals. They didn’t have time to bite the dolphins washed ashore, and foxes were excluded. Doubt.
Killer grey seal surfaced.
Finally, marine biologists finally locked in the killer of dolphins:grey seal.The canine teeth spacing of dolphin head wounds is about 5 cm, which is consistent with the canine characteristics of gray seals, who are used to controlling their prey with their forelimbs when hunting. Tag matching.
The next step is to test whether there is gray seal DNA on the wound of finless porpoise to confirm whether this gray seal is the murderer. But the killer’s saliva on the dolphin wound was washed away by the sea water, and the investigation was once again deadlocked.
In the following years, a large number of similar incidents occurred along the North Sea coast of Europe. Many finless porpoises were washed up on the coast, and researchers also observed for the first time that gray seals preyed on finless porpoises. It seems that there must be a direct connection between the death of gray seals and dolphins.
DNA confirms that grey seals can indeed prey on finless porpoises.
In 2014, scientists finally extracted the DNA of the gray seal from the wound of a dolphin corpse. Under a large amount of evidence, the real murderer of the finless porpoise killing incident was finally found. Just looking at the gray seals, no one will associate them with the death of porpoises, because gray seals, like cats, have round heads and big eyes and look very cute and friendly.
Scientists have always believed that gray seals feed on fish, shrimp, crabs, cephalopods and birds, and their food intake should not be very large, and they will not prey on cetaceans such as porpoises at all.
How crazy is the cannibal gray seal?
By the year before last, scientists had found 1081 finless porpoises in coastal areas of various countries. Through wound shape and DNA analysis, at least a quarter of dolphin deaths are related to gray seals.
Through research, it is found that although the gray seal is cute in appearance, it is ruthless in heart. They not only prey on small cetaceans such as porpoises, but also kill and eat each other. Seals are also very dangerous to humans and are likely to attack humans.
Gray seals have become top predators.
Gray seals are strong. The largest male gray seal can reach 3.3 meters in length and weigh 600 Jin, and the largest female gray seal can reach 2. The finless porpoise is the smallest of cetaceans, with a body length of only 1.2 to 1.5 meters. Gray seals have absolute strength in hunting porpoises.
When hunting, gray seals are used to catching their prey with their forelimbs and then inserting their teeth deeply into their prey. They also use this hunting technique to kill porpoises.
Earlier, scientists knew that gray seals often preyed on penguins, but the death of dolphins on the coast appeared one after another, which made people re-understand the cruel side of gray seals. Scientists speculate that gray seals seem to have become the most dangerous top predator in the North Sea.
In the past few decades, the number of gray seals has increased dramatically. There are 180,000 gray seals living in Britain alone, and their habitats and food are very limited, which also leads to fierce competition among gray seals. Willing to try new prey, among which spotted seals, porpoises and even the same kind have become the food of gray seals.
finally
Humans should have a correct understanding of every living thing and their real behavior. They should not understand these animals from the perspective of human beings, so as not to hurt themselves. As for the gray seals, humans should not use them. They should not be "cute" and "demonized".
The picture is from the network and must be deleted.
