This trumpet-shaped protozoan was captured in its never-ending feeding frenzy after being rescued from a stagnant pond in Tallahassee, Florida. The image was made using Hoffman modulation contrast illumination to view a sample of the pond on a microscope slide.

Stentor protozoa (Stentor polymorphus) are single-celled animals that grow to a length of 1.5 to 2 millimeters, much larger than many of their fellow multi-cellular aquatic organisms. Often, stentors will attach the lower portion of their pod to debris and assume the trumpet shape illustrated above. The circle of tiny cilia surrounding the trumpet rim beat continuously and serve to create localized convection currents in the water to draw smaller organisms into the rim or mouth (cytostome). Stentors vary in color, depending upon their diet, but they can appear green, blue, or reddish-yellow.