Did a shark clash with large squid and live to tell the tale?
Underwater photographer Deron Verbeck was diving off the coast of Kona, Hawaii when he spotted an oceanic whitetip shark with strange scarring across its head and back. He snapped a photo of the shark with its scarring pattern of circles and dots that didn't look like teeth marks.
Verbeck brought the photo to Yannis Papastamatiou, Demian Chapman and Heather Bracken-Grissom—marine scientists in Florida International University's Institute of Environment. Obvious to them, the marks weren't from another shark. They appear to be caused by the suckers from a squid's tentacles—a rather large squid judging by the scars.
The FIU researchers believe this is the first time these markings have been observed on a shark.
While it's impossible to say for sure what attacked the shark, the marine scientists aren't ruling out the possibility that two of the ocean's most elusive creatures—the oceanic whitetip and the giant squid—may have clashed in the deep depths of the ocean.
Oceanic whitetips reside mostly in remote part of the ocean where food is scarce. This has made them difficult to study. Once considered one of the most abundant shark species in the world, they are now listed as threatened under the Endangered Species Act.
For more than a decade, Papastamatiou and Chapman have studied these enigmatic sharks. Using tracking tags and special sensors that record swim speed, acceleration and depth, they've been able to uncover details about their behavior.
Data has shown they dive deep. Very deep. Sometimes to depths of 1,000 feet below the surface. Researchers believe one of the reasons they do this is to forage for food, including smaller squid. They've even been observed following pods of pilot whales.
When any animal enters those great depths, though, they enter the territory of the phantom of the deep—the giant squid.
The team isn't sure what exactly went down, but they believe the squid was at least the same size as the oceanic whitetip—between 6 and 7 feet in length—but possibly larger. And that this didn't deter the shark from going after it.
Heather Bracken-Grissom, who was on a research team that captured the first-ever video of a giant squid in U.S. waters, says it's most likely the shark was on the hunt. She says the tentacle markings are similar to those seen on sperm whales, who are known hunters for large species of squid.
For the researchers, this interaction presents more questions than answers.
"This just shows that we still don't fully understand the interactions between these big animals in the open ocean or how the shallow and deep ecosystems are connected," Papastamatiou said.
The findings were recently published in the Journal of Fish Biology.
Journal information: Journal of Fish Biology
Provided by Florida International University