Single-Celled Cannibal Eats Its Own Clones

A microbe found in a Caribbean seawater filtration system doesn't just change behavior when food runs low. It changes form, doubling in size, reshaping its body, growing a larger mouth, and then systematically hunting and eating its own genetically identical relatives.

A team at Rensselaer Polytechnic Institute has found a single-celled organism with what amounts to a second career: it bulks up into a "supergiant," remodels its body, and starts eating its smaller clonal relatives. The findings, which made the cover of PNAS, challenge a working assumption that complex, regulated development belongs exclusively to multicellular animals.

Euplotes gigatrox is a newly described microbe, collected from a seawater filtration system on the Caribbean island of Curaçao. The supergiant form abandons filter-feeding entirely, switching to active predation: chasing down smaller clonal relatives and swallowing them at a pace of about one every 10 minutes. The prey is, to be precise, themselves, just smaller.

The cannibalistic giants tend to appear when food grows scarce and population growth slows. Yet they never make up more than about 5 percent of the population. Researchers believe this may be a form of biological risk management, with a small number of cells switching strategies to exploit a different food source when conditions change. Cells that shrink back down carry a distinct molecular signature, suggesting the transformation machinery gets temporarily switched off on the way out.

The name gigatrox, for what it's worth, is doing exactly the work it was assigned.

Read the full story at Rensselaer Polytechnic Institute, June 2, 2026

Hot Take: Anyone else picturing this as the single-celled version of the Hyde and Hare episode of the Bugs Bunny cartoon?