Stentor (Protozoan) Videos

Also known as the "trumpet animalcule," Stentor belongs to the class Spirotrichea in the phylum Ciliophora. They are some of the largest protozoans known and some species can be up to two millimeters (0.08 inch) long. Oftentimes, they are larger than many microscopic multicellular organisms such as rotifers and water fleas, and have been known to eat smaller members of these groups.

Like many other large, single-celled organisms, Stentor has more than one nucleus. The nuclei form a long strand, like a string of pearls. A contractile vacuole collects excess water and waste materials, which are periodically discharged to the outside. Hairlike cilia lining the "trumpet" beat rhythmically to create currents that draw particles, bacteria, and other small protozoans, into the cytostome (mouth) of the stentor.

Stentors are commonly found in most freshwater ponds, attached to vegetation or other surfaces where they generally spend their lives. When necessary, they can detach and use their cilia to move to another location. While swimming, they assume an oval or pear shape. Stentors have remarkable regenerative powers. A small fragment less than one-hundredth of the volume of an adult can grow into a complete organism.