The deep sea is the largest habitat on Earth and one of the least understood. To find out what happens when a large reptile sinks into the dark, researchers in Louisiana lowered three alligators to the seafloor. The result was a new species, a feast of strange scavengers and a mystery that is still unsolved.
The Great Gator Experiment
Marine scientists Craig McClain and Clifton Nunnally of the Louisiana Universities Marine Consortium (LUMCON) obtained three alligators culled by the state and sank them in early 2019 along the slope of the northern Gulf of Mexico, at about 6,600 feet (2,000 meters). Each carcass was strapped into a weighted harness.
The goal was to study food webs far below sunlight, where no plants grow and animals depend on whatever drifts down. Alligators and crocodiles are increasingly seen in marine habitats, and storms can wash them out to sea, but the aftermath of a “gator fall” had never been observed before. The team published its findings in PLOS ONE in December 2019.
Gator One: Visitors From the Deep
Scientists expected an alligator’s tough hide to slow scavengers down. Instead, football-sized giant isopods swarmed the first carcass within about a day, entering through weak points such as the eye sockets and armpits and eating from the inside out. Nunnally compared them to “deep sea vultures.” Amphipods, which look like tiny aliens, joined in.
Gator Two: Stripped Clean, Then a Surprise
When the team returned after 51 days, the second alligator had no soft tissue left at all. “There was not a single scale or scute left of that gator,” McClain told Atlas Obscura.
What remained was a skeleton covered in a red, shag-carpet-like fuzz. DNA analysis showed the fuzz was a species of Osedax, the so-called bone-eating or zombie worms, and it was new to science. It was the first time any Osedax had been found in the Gulf of Mexico, and the first recorded on alligator bones.
Gator Three: The Disappearance
The third alligator was the real puzzle. When researchers revisited the site eight days after the drop, the carcass was gone. All that was left was a large depression in the sand, plus the harness and weight, which had been dragged about 8 meters away.
The team says only a big predator could have done it. In the paper, the authors suggest a large elasmobranch, meaning a big shark or ray, and Atlas Obscura reports the likeliest candidates are a sixgill or Greenland shark. Despite online talk of giant squid and the Kraken, nobody saw what took the alligator, and the researchers have not proposed a sea monster.
Why It Matters
The results suggest large carcasses, even from land animals, can quickly become part of deep-sea food webs, though outcomes vary a lot. McClain has said researchers still don’t understand what role alligators and their relatives play in moving carbon from land to ocean.
Curious About the Deep Sea?
If this experiment sparked your interest in the ocean, here are some ways to explore it:
- Marine biology courses. Compare online marine biology courses, oceanography degrees and their tuition costs if you’re considering a career change.
- Streaming documentaries. A documentary streaming subscription puts deep-sea films on your screen.
- Ocean trips. Whale-watching tours, aquarium tickets and scuba diving trips are popular ways to see marine life.
- Dive gear and insurance. If you dive, compare scuba equipment, underwater cameras and dive travel insurance.
- Support ocean science. A donation to ocean research or conservation groups helps fund exploration.
Frequently Asked Questions
Who ran the Great Gator Experiment? Craig McClain and Clifton Nunnally of the Louisiana Universities Marine Consortium (LUMCON).
How deep were the alligators placed? About 6,600 feet (2,000 meters) in the northern Gulf of Mexico.
What did the scientists discover? A new species of bone-eating Osedax worm, which was the first Osedax recorded in the Gulf of Mexico.
What happened to the third alligator? It disappeared within eight days. Researchers think a large shark, such as a sixgill or Greenland shark, took it, but no one saw it happen.
Is there a monster in the Gulf of Mexico? There is no evidence of one. The most likely culprit is a large shark.
Sources: PLOS ONE, Atlas Obscura, Live Science, Gizmodo, SYFY WIRE, and the University of Louisiana at Lafayette, all covering the 2019 Great Gator Experiment in the Gulf of Mexico and the discovery of a new Osedax species.