Steinbeck compares the town to an animal in the beginning of chapter 3.
A town is a thing like a colonial animal. A town has a nervous system and a head and shoulders and feet. …. And a town has a whole emotion. (ch 3)
He uses this comparison to demonstrate how news travels quickly in a town, and how the town itself seems to have its own momentum. It is almost living and breathing on its own. The town itself is more than the sum of its parts. This is why the news of the pearl and Kino’s baby’s bite travels so fast.
Steinbeck describes the news also as moving on its own. It seems to move faster than people can tell it, because news travels fast in small towns when there is something important going on.