In a rare turn of events, seals in the coastal waters of Cape Town in South Africa have been caught killing and even eating sharks in the region - proof that sometimes the hunter can become the hunted.
A research team led by great white shark expert Chris Fallows discovered that not only do Cape fur seals have a taste for the internal organs of blue sharks, but that scientists may not understand the marine food chain as well as they thought.
Reported in the African Journal of Marine Science, back in December 2012 Fallows was leading what was supposed to be a normal shark dive 20 nautical miles southwest of Cape Point, the peninsula that curves out of Cape Town. What they ended up witnessing was more than they bargained for.
Surprisingly, when a group of 10 blue sharks showed up it was like ringing the dinner bell. A male Cape fur seal - about four and a half feet long, more or less the same size as a blue shark - started viciously attacking the predators. Fallows managed to capture the entire encounter on camera, making it the only known documentation of a seal going after and consuming mid-sized to large sharks.
According to The Smithsonian, Cape fur seals typically eat small fish, squid and crabs. And even though they are sometimes known to eat infant sharks or even scavenge food from deceased ones, a full-scale attack like this one has never been seen before. This particular seal consumed five of the 10 sharks.
"In more than 2,000 expeditions working with sharks over the last 21 years, this is the only time I have ever seen a seal kill several sharks and I can find no record of such an event happening elsewhere," Fallows told GrindTV at the time.
"Sharks of this size are certainly not usually considered food for seals," he added.
However, believe it or not this is not the first time Fallows has been in the right place at the right time to witness such an event. Back in 2004, while out on waters near Cape Point, he spotted a seal-also a young male-hunting and catching a blue shark. The seal tossed the shark into the air before eating its stomach and liver.
Cape fur seals and blue sharks are not only similar in size, but also have similar diets. While it would seem logical that a shark would take on a seal when competing for food, apparently Cape fur seals can turn the tables on their more ferocious foes at times.
Researchers believe that the seals may attack sharks to reduce competition in the ocean for food. Also, the seals may benefit from ingesting the organs of sharks, which are filled with high-energy nutrients.
Whether this is just a rare incidence of seal-on-shark behavior, or a bizarre form of predation that was previously unknown to scientists, remains to be seen. More research is needs to be conducted to find the answer. Until then, it seems that sharks may need to watch their backs.
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