In the murky depths off the coast of Hawaii, a furious battle between a shark and a giant squid once unfolded.
The duel only recently came to light after a marine photographer Deron Verbeck snapped an image of a large oceanic whitetip shark (Carcharhinus longimanus) off Hawaii’s coast of Kona in November 2019 and noticed its body was scarred with unusual circular marks. Verbeck passed the photographs on to marine biologists at Florida International University who guessed the marks were made by a large squid and, understandably, became fascinated with this unusual and unstudied encounter.
Reported in the Journal of Fish Biology, the team document their investigation into the image and attempt to explain what occurred.
"I was pretty shocked when I saw the pictures! I immediately thought it was from a large squid but am by no means an expert on squid. Luckily my colleague Heather Bracken-Grissom is, so I got her involved," Yannis Papastamatiou, study author and predator ecologist at Florida International University, told IFLScience.
"It is the first documented case I believe," he added. "Since this article came out a couple of folks have sent me pictures of sharks with similar markings but from smaller animals, so I would certainly say it’s rare but not maybe as rare as we might think."
The oceanic whitetip shark is believed to be around 2.2 meters (over 7 feet) long and featured an “unusual scarring pattern consisting of several bilayers of circles, running across the lateral flank,” the study authors write. In other words, the side of the shark was scarred with large circular sucker marks. Although this species of shark spends most of its time just 100 to 200 meters (328 to 656 feet) beneath the surface in seas across the world, they are known to take occasional excursions into depths of over 1,000 meters (3,280 feet) — the domain of giant squids.
The exact species of cephalopod could not be confirmed, but the researchers say the most likely culprit was a giant squid (Architeuthis), or other squid species from the genera Thysanoteuthis and Megalocranchia. Architeuthis can grow up to 13 meters (43 feet) from the tips of their tentacles to their head, which matches up to the size of the scars on the shark.
However, given the lack of knowledge about the elusive Architeuthis, it’s not possible to conclusively prove the shark’s scars are from a giant squid, although it remains a very clear possibility. Most of what scientists know about giant squids is based on studies of dead washed-up remains found on the shore. The first known photos of a living giant cephalopod in the wild only emerged in 2004 and footage of a live animal is still incredibly rare (check out the footage below).
It also remains unclear why the interaction occurred. Perhaps it was a disagreement over territory or an attempt at predation. Whatever the situation, the researchers believe that the shark was most likely the antagonist of the fight and the squid was just an unfortunate victim.
“Whether the sucker marks were defensive or offensive are unclear, but the lack of any obvious wounding suggests they were more likely defensive (i.e. the shark attacked the cephalopod). Similar scarring patterns are seen on sperm whales, well-known predators of large cephalopods,” the study authors write.