Ciliates

Ciliates are covered in part or entirely with what look like little bristles called cilia (the Latin word for eyelash.)

The cilia are used for locomotion, and to snag bacteria, algae and other food and direct it into the ciliate’s mouth-like opening.

three image of Didinium

Didinium, a ciliate that lives in fresh water, is a voracious hunter of live food such as Paramecium. A Didinium makes contact with a Paramecium and begins to ingest it. Courtesty of Mike Dingley, Microscopy UK.

Ciliates include both grazers that dine on algae and bacterial cells and predators that attack and gulp down other protozoa. Grazers include Paramecium and Vorticella. An example of a predatory ciliate is Didinium.

Ciliates are among the most complex of all single-celled creatures, with a diverse array of structures and organelles that perform a range of activities, from finding and catching food, digesting it, excreting it, moving about, respiring, sensing environmental conditions, and balancing the fluids inside their cells.

A few ciliates can grow up to 2 millimeters in length, big enough to be seen without a microscope.