In shocking outdoor news, a zombie shark was recently seen swimming around and hunting for prey with half of its body gone. That’s right. There’s a shark out there with a huge chunk of its body eaten away and it’s still swimming around doing shark things.
Dr. Mario Lebrato and his team at the Bazaruto Centre for Scientific Studies were releasing a blacktip shark back into the ocean off the coast of Mozambique when a group of bull sharks attacked, leaving the blacktip severely injured. Though, the zombie blacktip shark survived after struggling for about 20 minutes, said Lebrato. Photos can be seen here.
“Sharks eat sharks, that is well known,” he said. “But it is super difficult to film and document.” Lebrato managed to snap a few photos of the shark before it swam away. Who knows if it’s still alive at this point, but some part of me hopes it is, against all odds.
Sharks Cannibalize Each Other, But Why?
Sharks have been eating each other for as long as they’ve been around. When fossilized feces from the prehistoric orthacanthus were examined in 2017, it showed that the fossil contained baby shark teeth. Dr. Mark Meekan with the Australian Institute for Marine Science said at the time, “That shows that 300 million years ago these were cannibal sharks. Shark on shark predation is a fundamental trait.”
Now we’re seeing attacks like this one on the blacktip shark, and we’re wondering, why do sharks eat each other? The answer may lie in shark embryos.
Lamniform sharks–mako (like this one here), great whites (such as this one who mauled a swimmer), and threshers–continue to produce eggs after mating season. Due to a phenomenon called intrauterine cannibalism, developing sharks consume the extra eggs as a form of nourishment. This is called oophagy, which means egg-eating. In intrauterine cannibalism, the extra embryos aren’t fertilized, so we can’t quite consider it cannibalism. The embryos don’t contain any living material. But, there is another phenomenon called embryophagy.
Taking ‘Survival of the Fittest’ to Its Extreme
The website Sharkophile gives an example of embryophagy when talking about sand sharks, like this 7-foot sand shark someone reeled in recently. A female sand shark only gives birth to two live pups even though she can carry up to 10 embryos. When a pup hatches from its embryo they are about 2 inches long, but they have fully formed teeth. When they are almost 4 inches long, they start to target the other embryos, the unhatched and the smaller ones. The largest and most aggressive pups are the ones who survive in the womb. This already gives them a distinct advantage in life.
But, even before birth, sharks have to fight for their lives against their own kind. After birth, bigger, more aggressive sharks see the babies as easy pickings. Additionally, siblings will also try and eat each other. This is survival of the fittest at its most natural. Sharks eat each other to weed out the weak sharks and strengthen the gene pool. Alligators do the same thing. This allows for only the biggest and strongest sharks to survive the harsh realities of life.