草履虫 (zōrimo) is a type of single-celled organism known as a protozoan. It belongs to the group of ciliates, which are characterized by their hair-like structures called cilia. These cilia help the organism move and feed by creating water currents that bring food particles closer. 草履虫 can be found in various aquatic environments, including ponds and streams. They primarily feed on bacteria and small organic matter, playing an essential role in the ecosystem by helping to decompose organic material. Their simple structure and behavior make them a popular subject for study in biology and microbiology.