Tiger sharks are considered to be one of the most dangerous species of shark to humans. Nevertheless, it is very unlikely to be bitten or even killed. Singing birds fall, however, the predators much more often the victims.
Tiger sharks are in a class with Great White sharks and bull sharks, when it comes to unprovoked attacks on people. The statistical probability that a swimmer, Surfer or diver is bitten by a tiger shark and killed, is still rather low.
Since the end of the 16th century. Century was registered only just over a hundred tiger shark attacks. And less than a third of them ended fatally.
Now a study shows that songbirds have a much higher risk from tiger sharks than people.
More: sharks use Israel’s coast as a Jacuzzi
Marcus Drymon pumping a young tiger shark, the stomach is empty.
Collection of DNA samples from the stomach
A research team led by Marcus Drymond of the Mississippi State University had captured from the boat with a 105 young sharks in the Gulf of Mexico. The animals were not yet fully grown and less than a Meter long.
The scientists pumped the sharks stomach. After removal of the samples they left the predators unharmed into the water. 41 of them had bird remains in the stomach, including bone and feathers.
The biologist and his Team extracted the genetic Information from the gastric contents. To found to their Surprise, they DNA traces of an amazingly wide variety of bird species that you had not expected.
This typical country were living sparrows, swallows, pigeons and even woodpeckers in the United States also to the migratory birds. But what surprised the biologists most of all: they found no traces of water birds. “Underneath, there were no gulls, pelicans, cormorants, or any other type of sea bird,” said Dryman.
More: Why die sharks and rays in the sea in front of Bosnia and Herzegovina?
How to go to sharks on bird hunting?
The sharks don’t leave the water, of course, to hunt on the Land. The reason why they are so unusual loot can make, is more likely to be in the Flyway of the birds.
The sharks were during the migration seasons of birds in the Gulf of Mexico. “In any case, the time of the tiger shark, the bird ate fell, with the peak of the ornithological sightings for this species off our coast,” says Drymon.
“The tiger sharks began so sing birds had difficulty flying over the ocean,” adds Kevin Feldheim. He is the co-author of the study and a researcher at the Field Museum in Chicago. “You are already exhausted, and then you will be tired or fall during a storm into the sea.”
These feathers come from the stomach of tiger sharks. There are no Seabird feathers.
Birds that can’t swim are probably easier prey for sharks than of sea-birds, presumed to be in the Field. Seabirds are not able to escape the water better.
However, it is also known that adult tiger sharks can prey on young albatrosses. “There is a place in Hawaii, the baby Alba, the fly hawser to learn,” recalls Field. “Full-grown tiger sharks grab then.”
More: life with the great White shark
Watch the Video 01:16 Share
Why disappear the sharks of the Adriatic sea?
Facebook Twitter google+ send Tumblr VZ Xing Newsvine Digg
Permalink https://p.dw.com/p/2jEDI