Scientists Drop Dead Cow into Sea and Film Sleeper Sharks ‘Politely’ Lining Up to Feast
Scientists dropped a dead cow into the sea and captured footage of eight sleeper sharks appearing from the darkness and “politely” taking turns to feast on the carcass.
Researchers captured Pacific sleeper sharks on camera for the first time in the South China Sea, off China’s Hainan Island. The enormous deep-sea shark, which can grow up to 22 feet long, has never been filmed in this region before.
To capture this unprecedented footage, researchers from Sun Yat-sen University and the Southern Marine Science and Engineering Guangdong Laboratory dropped a cow carcass about 5,340 feet down to the seafloor and positioned cameras to monitor it.
To their surprise, the researchers saw not just one, but eight Pacific sleeper sharks show up to feed. The video even shows the sharks seeming to take turns, as if they were lining up.
The sleeper shark’s polite queuing behavior stood out to the scientists. According to a recent study, the footage suggests the sharks might have been following an order—those coming from behind were allowed to feed before the ones already at the carcass. The bigger sharks, over 8.8 feet long, went straight for the food. The smaller ones were more cautious, swimming around the carcass before taking a bite.
Researchers say they don’t yet know why the sharks behaved this way and seemingly obediently lined up to eat the carcass. Scientists have seen similar patterns when sharks feed on floating whale carcasses, but it’s also possible the first shark simply moved away to avoid a confrontation with a larger shark.
“This behavior suggests that feeding priority is determined by individual competitive intensity, even in deep-water environments, reflecting a survival strategy suitable for non-solitary foraging among Pacific sleeper sharks,” Han Tian, from Sun Yat-sen University and the Southern Marine Science and Engineering Guangdong Laboratory, says in a press release.
Pacific sleeper sharks live as deep as 2,000 meters below sea level and prefer continental slopes and shelves. They are stealthy predators and scavengers. Though they are usually found in the colder waters of the North Pacific and Arctic, this footage shows the species may travel much farther south than previously known.
Image credits: All photos and videos by Ocean-Land-Atmosphere Research.
