Cleavage furrow formation is the inward pinch of the cell membrane during cytokinesis in animal cells. A contractile ring of actin and myosin tightens to split one parent cell into two daughter cells.
Cleavage furrow formation is the membrane pinching step of cytokinesis in animal cells, when one cell physically splits into two. It happens after chromosomes have been separated, so the cell can finish division by dividing the cytoplasm, not just the nucleus.
The furrow starts where the cell’s middle is marked for division. At that spot, a contractile ring made of actin filaments and myosin motors assembles just under the plasma membrane. As myosin pulls on actin, the ring tightens like a drawstring and the membrane bends inward.
That inward bend is the cleavage furrow. It gets deeper as the ring continues to contract, eventually narrowing the connection between the two halves of the cell until the membrane is fully cut off into two separate daughter cells. This is the physical finish line of cell division in animal cells.
The timing matters. Cleavage furrow formation usually begins in late anaphase or telophase, after sister chromatids have moved apart. If the cell tried to divide too early, it could split before the chromosomes were safely separated, which would risk unequal genetic material in the new cells.
A good way to picture it is to compare it with plant cells. Animal cells can pinch inward because they do not have a rigid cell wall, so the membrane can constrict. Plant cells cannot do that, so they build a cell plate instead. That difference is one of the clearest visual clues for how cytokinesis works in different cell types.
The term also connects to cytoskeleton behavior. The actin-myosin ring is not random scaffolding, it is an organized machine that turns chemical energy into motion. When the ring contracts correctly, the daughter cells separate cleanly, with cytoplasm and organelles distributed into two new cells rather than left behind in one uneven mass.
Cleavage furrow formation is the part of cell division that turns a chromosome-splitting event into two real cells. Without it, mitosis might finish in the nucleus, but the cell would never physically separate, so you would not get two independent daughter cells.
In Cell Biology, this term sits right at the point where mitosis and cytokinesis meet. It helps explain why cell division is more than just chromosome movement. The cell also has to reorganize its membrane and cytoskeleton, and that means understanding actin, myosin, and the contractile ring together as one coordinated system.
It also gives you a clean comparison point for animal and plant cells. If you can explain why animal cells form a cleavage furrow while plant cells form a cell plate, you are showing that you understand how cell structure shapes the division process.
This term shows up again when you talk about genetic stability and division errors. If cleavage furrow formation fails or happens unevenly, the result can be abnormal daughter cells with missing or extra cytoplasm, and sometimes problems in organelle distribution or later development.
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Visual cheatsheet
view galleryCytokinesis
Cleavage furrow formation is one specific way cytokinesis happens in animal cells. Cytokinesis is the whole process of splitting the cytoplasm, while the furrow is the visible inward pinch that shows the membrane is being pulled apart. If you see a question about the end of cell division, this is often the step being described.
Contractile ring
The contractile ring is the structure that makes the furrow happen. It is built from actin and myosin, and its tightening force pulls the membrane inward. If the ring does not form correctly, the cell cannot make a normal cleavage furrow, so the two daughter cells may not separate cleanly.
Mitotic spindle assembly
Mitotic spindle assembly happens earlier and helps move chromosomes to opposite sides of the cell. Cleavage furrow formation comes after that movement is underway, so the cell divides only after the genetic material has been organized. These two steps work in sequence, even though one handles chromosomes and the other handles the membrane.
Daughter cells
The end result of cleavage furrow formation is two daughter cells. The furrow physically separates the parent cell into two new cells, each with its own cytoplasm and organelles. If the furrow forms unevenly, the daughter cells can end up unequal in size or contents.
A quiz item might show a diagram of an animal cell pinching in the middle and ask you to identify the structure or stage. In a short-answer question, you may need to trace the order of events, spindle separates chromosomes first, then the contractile ring tightens to form the cleavage furrow. In image-based questions, look for the inward dip in the membrane, which signals cytokinesis in an animal cell. If a prompt compares plant and animal cell division, use cleavage furrow formation as the animal-cell example and contrast it with cell plate formation. In lab work or class discussion, you might explain what would happen if the contractile ring failed, such as incomplete separation or abnormal daughter cells.
Cleavage furrow formation and cell plate formation both finish cytokinesis, but they happen in different kinds of cells. Animal cells pinch inward with a contractile ring, while plant cells build a new partition from the center outward because the rigid cell wall prevents pinching.
Cleavage furrow formation is the inward pinching of an animal cell membrane during cytokinesis.
The contractile ring, made of actin and myosin, creates the force that pulls the membrane inward.
This step happens after chromosomes have separated, usually in late anaphase or telophase.
Animal cells use a cleavage furrow, but plant cells use a cell plate instead.
If the furrow does not form correctly, the daughter cells may not separate normally or may end up uneven.
It is the inward pinching of the membrane that divides an animal cell into two daughter cells during cytokinesis. The contractile ring of actin and myosin tightens at the cell’s center until the membrane separates. It is the physical step that finishes cell division after chromosome separation.
A contractile ring made of actin filaments and myosin proteins forms just under the cell membrane. As myosin interacts with actin, the ring contracts and pulls the membrane inward. That constriction creates the furrow and eventually splits the cell.
Cleavage furrow formation happens in animal cells and pulls the membrane inward from the outside. A cell plate forms in plant cells, where vesicles fuse in the center and build a new dividing wall outward. The difference comes from the rigid plant cell wall.
It usually begins in late anaphase or telophase, after sister chromatids have moved apart. That timing keeps chromosome division and cytoplasmic division in the right order. If it started too early, the cell could split before the genetic material was safely separated.