Telocytes are a new type of interstitial cells. The most prominent morphological feature of telocytes is their very long and thin moniliform cellular prolongations with uneven thickness (telopodes) that can form cellular connections with surrounding homologous/heterogenous cells, blood vessels, and nerve endings. Telocytes are able to release extracellular vesicles and signal molecules, thus to exert their potential physiological functions. Previous studies have shown that the function of telocytes is related to the tissue regeneration in animals, therefore, the researches on telocytes in lower animals can help to further understand the mechanism of how telocytes participate in tissue regeneration and provide insights into human regenerative medicine. This review article summarizes the recent advances in researches on telocytes including their organ loeations, immunophenotypes, ultrastructural characteristics, structural relationships with surrounding cells, and functions in different animal species. The ultrastructure differences of telocytes in tissues and organs of different animals are also discussed. This review aims to help researchers further understand the biological characteristics and potential physiological functions of telocytes.