This tiny organism can shrink to one quarter its size in milliseconds

A tiny aquatic organism made of just one cell can compress its body to one quarter of its original length in under five milliseconds, hundreds of times faster than a person can blink. Scientists have now identified the unusual mechanism behind this remarkable movement.

The organism, Spirostomum ambiguum , relies on calcium ions and a specialized protein network arranged like a fishnet. This system allows it to contract far more quickly than human muscle, and researchers say the discovery could eventually help guide the development of faster artificial muscles and synthetic cellular machinery.

Spirostomum ambiguum is a giant single-celled ciliate, named for the fringe of hairlike cilia it uses to swim. Among ciliates, it stands out for its ability to contract at roughly 100 body lengths per second and then rapidly repeat the movement. Scientists think this behavior may help the organism escape predators or communicate with other ciliates.