Elusive Giants Spotted 1,800 Miles from Home in Surreal Deep Ocean Encounter

In the silent dark of the South China Sea, a cow carcass sank to the seafloor. Researchers had lowered it as bait, aiming to study scavenging in the deep. What they got instead was a rare glimpse of an elusive predator, thousands of miles from home.

Cameras positioned at 1,629 meters beneath the surface captured Pacific sleeper sharks arriving one by one to feast. These deep-dwelling giants, usually found in frigid northern waters, had never before been seen in this region. As Earth.com reports, their appearance dramatically expanded the known range of the species, long believed to haunt only the North Pacific from Japan to Baja California.

Photo: Wikimedia Commons / National Oceanic and Atmospheric Administration, License: Public Domain

Pacific sleeper sharks were filmed in the South China Sea for the first time.

Unexpected Guests at a Deep-Sea Banquet

The encounter unfolded southeast of Hainan Island, where the baited cameras revealed not just the presence of these sharks, but a host of new behaviors. Researchers from Sun Yat-sen University and the Southern Marine Science and Engineering Guangdong Laboratory documented a scene that stunned even seasoned marine biologists. The sharks didn’t swarm mindlessly. They queued.

Large sharks—those longer than 2.7 meters—approached the carcass directly, ripping off flesh in assertive lunges. Smaller ones held back, circling cautiously before moving in. The footage showed that individuals arriving from behind were given feeding priority, as those already eating respectfully yielded position, according to Phys.org.

It was as if deep-sea etiquette governed the feast. Scientists believe this queue-like behavior may reflect a social structure among Pacific sleeper sharks that helps reduce conflict over scarce food in the abyss.

All sharks recorded in the footage were female.

Protecting Their Eyes Without Eyelids

As the sharks fed, they exhibited a defensive eye retraction. Unlike many other shark species, Pacific sleepers lack a nictitating membrane—the protective “eyelid” that shields eyes during bites. Instead, they appear to roll their eyes back into their sockets as they lunge toward prey, a behavior scientists believe evolved to guard against sharp bones or rival teeth, Discover Wildlife reports. The unique motion was captured on the deep-sea video system and may be critical for the sharks' survival in aggressive feeding scenarios.

Why Are They So Far From Home?

Pacific sleeper sharks are typically found in icy waters with depths over 1,000 meters. That they appeared here, more than 1,800 miles south of their known range, raises significant questions about what’s changing in their environment.

Do warming ocean currents explain the shift? Or is it the South China Sea’s deep food supply that draws them in? The fact that every individual recorded during the study was female adds another layer of intrigue.

Female-skewed sightings in this region are not unique to this species—other deep-sea sharks like the megamouth also show similar patterns here. Scientists now wonder whether the area may serve as a critical nursery ground for certain large sharks, as Metro reports.

Photo: Wikimedia Commons / Fujiwara Y, Matsumoto Y, Sato T, Kawato M, Tsuchida S., License: CC BY 4.0

Record of the swimming speed of the Pacific sleeper shark

Energy Flows from Surface to Seafloor

Pacific sleeper sharks usually hunt squid, fish, and marine mammals—or scavenge what they can find. Their appearance around a cow carcass in the deep tropics hints at robust nutrient flows ferrying organic matter down from surface ecosystems.

That rich food pathway might be what sustains them here, according to Han Tian, the study’s lead researcher. He told Earth.com that the highly aggressive feeding they observed suggests a healthy prey population in these abyssal depths. But the specifics of those food sources remain a mystery.

Looking for More Clues in the Dark

This discovery has set off a new wave of research. The team plans to deploy more baited camera rigs across the South China Sea. According to The Economic Times, they’ll also use environmental DNA to track whether these sharks are seasonal visitors or permanent residents. The findings could reshape our understanding of how life moves, feeds, and reproduces in one of Earth’s least-known frontiers.

This isn’t just about sharks. It’s about the deep ocean’s role in the global carbon cycle, in predator-prey dynamics, and in sustaining biodiversity we still barely comprehend. For now, though, a single cow dropped into the dark has opened a bright new chapter in marine science.