Definition of Cleavage Furrow

A cleavage furrow develops on the surface of the cell at that moment when the cell is preparing itself to divide. It is formed when the contractile ring, a proteinaceous structure composed of actin and myosin, starts pinching the cell membrane inwards. The ring squeezes the cell membrane to such a point that the parental cell is divided into two daughter cells.

This phenomenon happens due to the ability to actin and myosin to relax and contract. This cleavage furrow appears in the cells of animals and algae. The plant cells have an outer cell wall which is quite a rigid structure so they do not form a cleavage furrow but a cell plate.