Parting appears to be sweet sorrow for a pair of Madin-Darby bovine kidney cells. Though only 21 seconds long during the high speed playback of the time-lapse sequence, the lingering farewell between the cells actually unfolded over the course of seven hours. Notice that the lamellipodia along the leading margins of the cells attempt to carry them in opposite directions, but the tails of the cells just do not seem to want to let go of one another.

As each broad lamellipodium is stretched out over the culture medium, sites of close adhesion to the substratum, called focal adhesions, are formed. As if they were microscopic feet, the focal adhesions remain in place as the cell advances over them. Once they move further toward the rear of the advancing cell, however, they are usually detached from the surface.

The tail of a migrating cell is known as a uropod or retraction fiber. The fiber possesses contractile properties and usually is quickly retracted back into the main body of the cell periodically, like a rubber band stretched too far. This snapping-like phenomenon is clearly demonstrated when the two featured MDBK cells finally achieve separation and continue migrating along their individual paths.