The characteristics of the substratum that an animal cell crawls across influence the behavior of that cell. Surface receptors possessed by the cells demonstrate recognition of molecules present, for instance, along the bottom of an imaging chamber. Some of the molecules instigate the growth of lamellipodia or other surface extensions, while others elicit retraction. Studies show that the physical properties of a surface can influence cell dynamics as well, with some cells demonstrating distinct preferences for certain types of terrain. The affinity a cell has for its substratum can greatly impact its migratory behavior.

Fibroblasts generally form strong connections called focal adhesions with surfaces covered in culture medium. Some of the A. P. Mongoose fibroblasts appearing in this time-lapse sequence develop such tight focal adhesions with the substratum that they are not able to release all of them during their travels. Consequently, the material present at the attachment sites are severed from the rest of the cells so that they do not hinder their forward progression.

Several of the cytoplasmic fragments left behind by migrating cells can be seen in the left half of the field of view early during the high speed playback of the time-lapse sequence. Like microscopic street sweepers, actively locomoting A. P. Mongoose fibroblasts attempt to clean up all of the debris they encounter. One of the cells traveling over from the right-hand side of the field of view seems particularly aggressive in its pursuit of the cell fragments. After circling around the area where the bulk of the debris can be found, the fibroblast extends its flattened lamellipodia down almost the entire field of view, forming a large triangle, which enables it to sweep up the remaining cellular debris and incorporate it into its own contents.