A shark is stabbed in the head and washed ashore in Los Cabos
On a sunny day in February, there was a strange sight on the beach in Los Cabos, Mexico. A dead mako shark with a stabbed head.
The weapon was still embedded in the head of a young shark, but it’s a mysterious “whodunit.” A significant number of marine animals have pointed “swords” that they usually wield in self-defense.Based on the size of this particular spike, it may be marlin, sailfish, or StingrayChristopher Rowe, a professor of marine biology and director of the Shark Institute at California State University Long Beach, said all underwater residents of the Los Cabos area examined photographs of stabbed sharks.
Adult mako sharks always eat animals with “swords”. It is likely that this little mako shark (Isurus oxyrinchus) I tried to eat but failed, Rowe said. “This was a young one, probably inexperienced and trying to catch an unprepared prey,” Rowe told Live Science.
Adult mako sharks can Reach 12 feet (3.8 meters) in length It weighs at least 1,200 pounds (545 kilograms). However, these sharks were born about 3 feet (1 m) long, and the sharks are just a little longer, according to the picture. 3 feet wide (1 m) Adult stingray.
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The incident occurred on February 18, and Arturo Chacon, who found a shark while walking on the beach of San Jose del Cabo, is known as Los Cabos, a popular tourist destination in the northwest along with Cabo San Lucas. .. Mexico. “It was fresh or seemed to have died a while ago,” said owner and CEO Chacon. Tag Cabo Sport Fishing, Told live science.
He took some pictures of sharks and posted them Instagram“The shark was washed away on the beach in San Jose del Cabo. Apparently I lost the fight against the big stingray! Wow!”
It is not clear which animal stabbed the shark, but stingrays have serrated pointed spines. If it was a stingray, it was probably a pelagic stingray (Pteroplatytrygon violacea), A creature with a defensive spine, also known as a thorn, on the dark purplish-gray underside and the tail used to pierce the animals that threaten it, Rowe said. Pelagic stingrays live in the open ocean, and their habitat overlaps with the habitat of shortfin mako sharks, Rowe said.
Stingray thorns are toxic, but rarely deadly, Rowe said. However, there are exceptions. In 2006, Australian television personality Steve Irwin, known for his popular show “Crocodile Hunter,” announced the poisonous spine of a short-tailed stingray.Dasyatis brevicaudata) It pierced his heart. However, it is not uncommon to see live sharks filled with stingray spines.
Stingrays can also rotate. Females can use their spine to drive off amorous males, and stingrays can use their spine to grow another spine, Rowe said. “When the females finish mating and the males try to mate, they will spin the junk from them,” Rowe said. “You can see a man with all these holes in it.”
So what killed the young Mako if the thorns weren’t usually deadly?
Judging from the pictures taken by Chacon, the spine doesn’t look like it pierced the shark’s brain, Rowe said. “It’s hard to say, but [the spine] “The shark’s brain is strange. There’s a lot of space and there’s not much brain. There’s a lot of fluid that fills the chondrocranium, which is the neurocranium, and the brain is relatively small.”
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The spine may have damaged the shark’s forebrain or part of the olfactory bulb, “which may have affected the shark’s olfactory ability,” Rowe said. “We will have to do an autopsy, whether it was fatal or not. [an animal autopsy] in addition. “
What is surprising here is that sharks were found on the beach. Sharks have a negative buoyancy, so when they die they usually sink to the bottom of the sea, Rowe said. “Based on this scar, I guess the animal was disorientated, swam into the coastline, and landed on the beach there,” he said. Or, after the shark was stabbed, “a fisherman caught the shark and unhooked it, but it didn’t work because he was beaten,” Rowe said.
After further analysis of the photographs, Rowe said the spine may not belong to the pelagic stingray. “Stingray spines tend to be more rectangular or flat, but this looks too thick in diameter,” he later wrote to Live Science by email. “Another possibility is the tip of invoices from marlin and sailfish.”
Fish with these swords are known to sting sharks trying to eat them, Rowe said. However, this is not always the case. Thresher shark in 2020Alopias superciliosus), A journal study in which a shark that does not prey on swordfish was washed ashore in Libya with a sword protruding from its body. Ichthyology research report. It’s unclear what happened, but scientists suggest that the swordfish may have attacked the shark because the stab wound was accidental or because the two animals were competing for the same prey. Did. Live Science previously reported..
Originally published in Live Science.
A shark is stabbed in the head and washed ashore in Los Cabos
Source link A shark is stabbed in the head and washed ashore in Los Cabos
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