What will pearls do on Marapets?

From what my understanding is, Pearls are used mainly for quests. On a side note, most items can be used with your pet. Pearls, in this case, can be used to play with your pet to increase their happiness level.

Pearls are also used by collectors to, I believe, get a pearl avatar of some sort.

Marapets Username: Callacose

Hope this helps!