Figure 2-2. Rat runways.
across the runway or a film of dust obscuring the tracks. Additional evidence as to the
age and activity of the run can be obtained from a closer examination of the greasy rub
marks mentioned above. In active runs, the grease on these marks will be soft and will
stick to the finger when touched lightly. In abandoned runs, the grease will be hard and
dusty. When old rub marks are scratched across lightly with the fingernail, clear,
knifelike lines result.
c. Tracks. Rat tracks are quite distinctive. The tracks of the five-toed, rear
paws are seen more commonly than those of the four-toed, front paws, but both may be
present. When moved slowly over flat surfaces, the tail may leave wavy lines. Such tail
markings sometimes indicate the age of the rat because old rats drag their tails and
young rats tend to carry them in the air. Various-sized tracks indicate the presence of
rats of different sizes and ages. The tracks may be erased, and the site observed for a
period to learn if the animals are still present. Ordinary wheat flour or other similar
material may be dusted around an area to form a patch in which freshly made tracks will