The cleavage furrow is the indentation of the cell's surface that begins the progression of cleavage, by which animal and some algal cells undergo cytokinesis, the final splitting of the membrane, in the process of cell division.
The cleavage furrow mechanism in animal cells is a complex network of actin and myosin filaments, Golgi vesicles and Calcium dependent channels enabling the cell to break apart, reseal and form new daughter cells with complete membranes.