sharats, “to teem,” strong’s H8317

First occurrence

And God said, “Let the waters swarm with swarms of living creatures, and let winged creatures fly above the earth in the open firmament of heaven.” Gen 1:20

The primitive root

Strong’s H8317 שרץ sharats, a primitive root meaning, “to teem.” The ancient pictographs are shin + resh + tsadey:

shin ש = two front teeth, thus sharp, press, eat, two, again
resh ר = the head of man, thus head, first, top, beginning, man
tsadey צ, ץ = the trail, thus a man concealed, journey, chase, hunt

The two front teeth (shin) conveys the idea of plurality and multiplication, as anything x2 increases its number. The parable being told is thus multiplied  (shin) heads (resh) which creep (as a hunter does along a trail, tsadey); i.e., the swarming of creeping things.

THE ANCIENT HEBREW LEXICON | INDEX OF HEBREW ROOTS